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Posted to commits@stratos.apache.org by is...@apache.org on 2013/07/10 18:51:45 UTC

[10/45] fixing component version issues and adding currently refactored components to the parent pom

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/pom.xml
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diff --git a/components/org.apache.stratos.mediator.autoscale/pom.xml b/components/org.apache.stratos.mediator.autoscale/pom.xml
new file mode 100644
index 0000000..e07b9d0
--- /dev/null
+++ b/components/org.apache.stratos.mediator.autoscale/pom.xml
@@ -0,0 +1,135 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     ~  Licensed to the Apache Software Foundation (ASF) under one
+     ~  or more contributor license agreements.  See the NOTICE file
+     ~  distributed with this work for additional information
+     ~  regarding copyright ownership.  The ASF licenses this file
+     ~  to you under the Apache License, Version 2.0 (the
+     ~  "License"); you may not use this file except in compliance
+     ~  with the License.  You may obtain a copy of the License at
+     ~
+     ~    http://www.apache.org/licenses/LICENSE-2.0
+     ~
+     ~  Unless required by applicable law or agreed to in writing,
+     ~  software distributed under the License is distributed on an
+     ~  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+     ~  KIND, either express or implied.  See the License for the
+     ~  specific language governing permissions and limitations
+     ~  under the License.
+     ~
+ -->
+
+
+<!--
+We need to modify this file since this copied from branch
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+    <parent>
+        <groupId>org.apache.stratos</groupId>
+        <artifactId>stratos-components-parent</artifactId>
+        <version>3.0.0-SNAPSHOT</version>
+    </parent>
+
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>org.apache.stratos</groupId>
+    <artifactId>org.apache.stratos.mediator.autoscale</artifactId>
+    <packaging>bundle</packaging>
+    <name>Apache Stratos - Autoscale Mediator BE</name>
+    <url>http://apache.org</url>
+
+    <build>
+        <plugins>
+			<plugin>
+                <groupId>org.apache.felix</groupId>
+                <artifactId>maven-scr-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.felix</groupId>
+                <artifactId>maven-bundle-plugin</artifactId>
+                <version>1.4.0</version>
+                <extensions>true</extensions>
+                <configuration>
+                    <instructions>
+                        <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
+                        <Bundle-Name>${project.artifactId}</Bundle-Name>
+                        <Export-Package>
+                            !org.org.apache.stratos.mediator.autoscale.lbautoscale.internal,
+                            org.apache.stratos.mediator.autoscale.*
+                        </Export-Package>
+                        <Private-Package>org.apache.stratos.mediator.autoscale.lbautoscale.internal</Private-Package>
+                        <Import-Package>
+                            !javax.xml.namespace,
+                            javax.xml.namespace; version=0.0.0,
+                            !org.apache.commons.logging,
+                            org.apache.commons.logging; version=0.0.0,
+                            org.apache.axis2.*,
+                            org.apache.synapse.*,
+                            org.wso2.carbon.task.*; version=0.0.0,
+                            org.wso2.carbon.core.*,
+                            org.apache.stratos.lb.common.*,
+                            org.apache.stratos.load.balance.cartridge.autoscaler.service.stub.*; version=0.0.0,
+                            org.wso2.carbon.utils.*,
+                            org.apache.axiom.om; version="${axiom.osgi.version.range}",
+                            org.apache.stratos.cloud.controller.*,
+                            *; resolution:=optional
+                        </Import-Package>
+                        <DynamicImport-Package>*</DynamicImport-Package>
+                    </instructions>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+          <groupId>org.apache.axis2.wso2</groupId>
+          <artifactId>axis2</artifactId>
+          <version>1.6.1.wso2v9</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.synapse</groupId>
+            <artifactId>synapse-core</artifactId>
+            <version>${synapse.core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.stratos</groupId>
+            <artifactId>org.apache.stratos.load.balance.cartridge.autoscaler.service.stub</artifactId>
+            <version>${apache.stratos.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.wso2.carbon</groupId>
+            <artifactId>org.wso2.carbon.core</artifactId>
+            <version>${wso2carbon.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.wso2.carbon</groupId>
+            <artifactId>org.wso2.carbon.utils</artifactId>
+            <version>${wso2carbon.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.stratos</groupId>
+            <artifactId>org.apache.stratos.lb.common</artifactId>
+            <version>${apache.stratos.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.stratos</groupId>
+            <artifactId>org.apache.stratos.cloud.controller</artifactId>
+            <version>${apache.stratos.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.wso2.carbon</groupId>
+            <artifactId>org.wso2.carbon.task</artifactId>
+            <version>${wso2carbon.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.synapse</groupId>
+            <artifactId>synapse-tasks</artifactId>
+            <version>2.1.1-wso2v4</version>
+        </dependency>
+
+    </dependencies>
+
+</project>

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AppNodeSanityCheckCallable.java
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diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AppNodeSanityCheckCallable.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AppNodeSanityCheckCallable.java
new file mode 100644
index 0000000..c535489
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@@ -0,0 +1,86 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+
+package org.apache.stratos.mediator.autoscale.lbautoscale.callables;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.lb.common.conf.LoadBalancerConfiguration.ServiceConfiguration;
+import org.apache.stratos.mediator.autoscale.lbautoscale.clients.CloudControllerClient;
+import org.apache.stratos.mediator.autoscale.lbautoscale.context.AppDomainContext;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscaleUtil;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+
+import java.util.concurrent.Callable;
+
+/** Performing sanity checks for each service domain, sub domain combination **/
+public class AppNodeSanityCheckCallable implements Callable<Boolean> {
+
+    private static final Log log = LogFactory.getLog(AppNodeSanityCheckCallable.class);
+    private String domain;
+    private String subDomain;
+    private CloudControllerClient client;
+    private AppDomainContext appDomainContext;
+    private ServiceConfiguration serviceConfig;
+    
+    public AppNodeSanityCheckCallable(String domain, String subDomain, CloudControllerClient client, AppDomainContext appCtxt){
+        this.domain = domain;
+        this.subDomain = subDomain;
+        this.client = client;
+        this.appDomainContext = appCtxt;
+        serviceConfig =
+                AutoscalerTaskDSHolder.getInstance().getWholeLoadBalancerConfig().getServiceConfig(this.domain,
+                    this.subDomain);
+    }
+    
+    @Override
+    public Boolean call() throws Exception {
+
+        if (appDomainContext != null) {
+            int currentInstances = 0;
+            // we're considering both running and pending instance count
+            currentInstances = appDomainContext.getInstances();
+
+            int requiredInstances = serviceConfig.getMinAppInstances();
+
+            // we try to maintain the minimum number of instances required
+            if (currentInstances < requiredInstances) {
+                log.debug("App domain Sanity check failed for " +
+                    AutoscaleUtil.domainSubDomainString(domain, subDomain) +
+                        " . Current instances: " +
+                        currentInstances +
+                        ". Required instances: " +
+                        requiredInstances);
+
+                int diff = requiredInstances - currentInstances;
+
+                // Launch diff number of App instances
+                log.debug("Launching " +
+                    diff +
+                    " App instances for " +AutoscaleUtil.domainSubDomainString(domain, subDomain));
+
+                // FIXME: should we need to consider serviceConfig.getInstancesPerScaleUp()?
+                AutoscaleUtil.runInstances(client, appDomainContext, this.domain, this.subDomain, diff);
+            }
+        }
+
+        return true;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AutoscaleDeciderCallable.java
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diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AutoscaleDeciderCallable.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/AutoscaleDeciderCallable.java
new file mode 100644
index 0000000..84705bb
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@@ -0,0 +1,241 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.callables;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.lb.common.conf.LoadBalancerConfiguration.ServiceConfiguration;
+import org.apache.stratos.mediator.autoscale.lbautoscale.clients.CloudControllerClient;
+import org.apache.stratos.mediator.autoscale.lbautoscale.context.AppDomainContext;
+import org.apache.stratos.mediator.autoscale.lbautoscale.state.check.TerminatingInstancesStateChecker;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscaleUtil;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+
+import java.util.concurrent.Callable;
+
+/** Take auto-scaling decisions for each service domain, sub domain combination **/
+public class AutoscaleDeciderCallable implements Callable<Boolean> {
+
+    private static final Log log = LogFactory.getLog(AutoscaleDeciderCallable.class);
+    private String domain;
+    private String subDomain;
+    private CloudControllerClient client;
+    private AppDomainContext appDomainContext;
+    private ServiceConfiguration serviceConfig;
+    private String clusterStr;
+    
+    public AutoscaleDeciderCallable(String domain, String subDomain, CloudControllerClient client, AppDomainContext appCtxt){
+        this.domain = domain;
+        this.subDomain = subDomain;
+        this.client = client;
+        this.appDomainContext = appCtxt;
+        clusterStr = AutoscaleUtil.domainSubDomainString(domain, subDomain);
+    }
+    
+    @Override
+    public Boolean call() throws Exception {
+
+        // expire tokens
+        if (appDomainContext != null) {
+            appDomainContext.expireRequestTokens();
+
+            serviceConfig = appDomainContext.getServiceConfig();
+
+            appDomainContext.recordRequestTokenListLength();
+            if (!appDomainContext.canMakeScalingDecision()) {
+                return true;
+            }
+
+            long average = appDomainContext.getAverageRequestsInFlight();
+            int runningAppInstances = appDomainContext.getRunningInstanceCount();
+            int terminatingAppInstances = appDomainContext.getTerminatingInstanceCount();
+
+            int maxRPS = serviceConfig.getMaxRequestsPerSecond();
+            double taskInterval =
+                AutoscalerTaskDSHolder
+                    .getInstance()
+                    .getWholeLoadBalancerConfig()
+                    .getLoadBalancerConfig()
+                    .getAutoscalerTaskInterval() / (double)1000;
+            double aur = serviceConfig.getAlarmingUpperRate();
+            double alr = serviceConfig.getAlarmingLowerRate();
+            double scaleDownFactor = serviceConfig.getScaleDownFactor();
+
+            // scale up early
+            double maxhandleableReqs = maxRPS * taskInterval * aur;
+            // scale down slowly
+            double minhandleableReqs = maxRPS * taskInterval * alr * scaleDownFactor;
+
+            if (log.isDebugEnabled()) {
+                log.debug(clusterStr +": Average requests in flight: " + average + " **** Handleable requests: " +
+                    (runningAppInstances * maxhandleableReqs));
+            }
+            if (average > (runningAppInstances * maxhandleableReqs) && maxhandleableReqs > 0) {
+                
+                // estimate number of instances we might want to spawn
+                int requiredInstances = (int) Math.ceil(average/maxhandleableReqs);
+                
+                log.debug(clusterStr+" : Required instance count: "+requiredInstances);
+                
+                // current average is higher than that can be handled by current nodes.
+                scaleUp(requiredInstances - runningAppInstances);
+            } else if (terminatingAppInstances == 0 && average < ((runningAppInstances - 1) * minhandleableReqs)) {
+                // current average is less than that can be handled by (current nodes - 1).
+                scaleDown();
+            }
+        }
+
+        return true;
+    }
+
+    private void scaleDown() {
+
+        int runningInstances = appDomainContext.getRunningInstanceCount();
+//        int pendingInstances = appDomainContext.getPendingInstanceCount();
+        int terminatingInstances = appDomainContext.getTerminatingInstanceCount();
+        int minAppInstances = serviceConfig.getMinAppInstances();
+//        int serverStartupDelay = AutoscalerTaskDSHolder
+//                                            .getInstance()
+//                                            .getWholeLoadBalancerConfig()
+//                                            .getLoadBalancerConfig()
+//                                            .getServerStartupDelay();
+
+        if ( (runningInstances - terminatingInstances) > minAppInstances) {
+
+            if (log.isDebugEnabled()) {
+                log.debug("Scale Down - " +
+                    clusterStr +
+                        ". Running instances:" +
+                        runningInstances +
+                        ". Terminating instances: " +
+                        terminatingInstances +
+                        ". Min instances:" +
+                        minAppInstances);
+            }
+            // ask to scale down
+            try {
+                if (client.terminateInstance(domain, subDomain)) {
+                    
+                    Thread th = new Thread(new TerminatingInstancesStateChecker(appDomainContext, domain, subDomain));
+                    th.start();
+                    
+//                        log.debug(clusterStr +": There's an instance who's in shutting down state " +
+//                            "(but still not left ELB), hence we should wait till " +
+//                            "it leaves the cluster.");
+//
+//                        int totalWaitedTime = 0;
+//
+//                        log.debug(clusterStr +": Task will wait maximum of (milliseconds) : " +
+//                            serverStartupDelay +
+//                                ", to let the member leave the cluster.");
+//                        
+//                        // for each sub domain, get the clustering group management agent
+//                        GroupManagementAgent agent =
+//                            AutoscalerTaskDSHolder.getInstance().getAgent()
+//                                .getGroupManagementAgent(domain,
+//                                    subDomain);
+//
+//                        // we give some time for the server to be terminated, we'll check time to time
+//                        // whether the instance has actually left the cluster.
+//                        while (agent.getMembers().size() == runningInstances &&
+//                            totalWaitedTime < serverStartupDelay) {
+//
+//                            try {
+//                                Thread.sleep(AutoscaleConstants.INSTANCE_REMOVAL_CHECK_TIME);
+//                            } catch (InterruptedException ignore) {
+//                            }
+//
+//                            totalWaitedTime += AutoscaleConstants.INSTANCE_REMOVAL_CHECK_TIME;
+//                        }
+//
+//                        log.debug(clusterStr+ " : task waited for (milliseconds) : " + totalWaitedTime);
+//
+//                        // we recalculate number of alive instances
+//                        runningInstances = agent.getMembers().size();
+//                        
+//                        appDomainContext.setRunningInstanceCount(runningInstances);
+//
+//                        log.debug(clusterStr+" : New running instance count: " + runningInstances);
+                }
+
+            } catch (Exception e) {
+                log.error("Instance termination failed for " + clusterStr, e);
+            }
+        }
+
+    }
+
+    private void scaleUp(int requiredInstanceCount) {
+
+        int maxAppInstances = serviceConfig.getMaxAppInstances();
+//        int instancesPerScaleUp = serviceConfig.getInstancesPerScaleUp();
+//        int runningInstances = appDomainContext.getRunningInstanceCount();
+//        int pendingInstances = appDomainContext.getPendingInstanceCount();
+        int totalInstanceCount = appDomainContext.getInstances();
+        
+        log.debug(AutoscaleUtil.domainSubDomainString(domain, subDomain)+ " - Total Running/Pending instance count: "+totalInstanceCount);
+        
+        if(maxAppInstances > totalInstanceCount){
+            
+            int availableQuotaOfInstances = maxAppInstances - totalInstanceCount;
+            
+            log.debug(AutoscaleUtil.domainSubDomainString(domain, subDomain)+ " - Available Quota of Instances: "+availableQuotaOfInstances);
+            
+            requiredInstanceCount = requiredInstanceCount <= availableQuotaOfInstances ? requiredInstanceCount : availableQuotaOfInstances;
+            
+            log.debug(clusterStr + " - Going to start " +
+                    requiredInstanceCount + " instance/s.");
+
+                AutoscaleUtil.runInstances(client, appDomainContext, domain, subDomain,
+                    requiredInstanceCount);
+                
+        } else if (totalInstanceCount > maxAppInstances) {
+            log.fatal("Number of running instances has over reached the maximum limit of " +
+                maxAppInstances + " of " + clusterStr);
+        }
+
+//        int failedInstances = 0;
+//        if (runningInstances < maxAppInstances && pendingInstances == 0) {
+//
+//            log.debug(clusterStr + " - Going to start " +
+//                    requiredInstanceCount + " instance/s. Running instances:" + runningInstances);
+//
+//                AutoscaleUtil.runInstances(client, appDomainContext, domain, subDomain,
+//                    requiredInstanceCount);
+
+//            if (successfullyStarted != instancesPerScaleUp) {
+//                failedInstances = instancesPerScaleUp - successfullyStarted;
+//                if (log.isDebugEnabled()) {
+//                    log.debug(successfullyStarted +
+//                        " instances successfully started and\n" + failedInstances +
+//                        " instances failed to start for " + clusterStr);
+//                }
+//            }
+//
+//            // we increment the pending instance count
+//            // appDomainContext.incrementPendingInstances(instancesPerScaleUp);
+//            else {
+//                log.debug("Successfully started " + successfullyStarted +
+//                    " instances of " + clusterStr);
+//            }
+
+       
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/InstanceCountCallable.java
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diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/InstanceCountCallable.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/InstanceCountCallable.java
new file mode 100644
index 0000000..90c2c3a
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@@ -0,0 +1,78 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.callables;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.mediator.autoscale.lbautoscale.clients.CloudControllerClient;
+import org.apache.stratos.mediator.autoscale.lbautoscale.context.AppDomainContext;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+/** Calculate instances of each service domain, sub domain combination **/
+public class InstanceCountCallable implements Callable<Boolean> {
+
+    private static final Log log = LogFactory.getLog(InstanceCountCallable.class);
+    private String domain;
+    private String subDomain;
+    private CloudControllerClient client;
+    private AppDomainContext appCtxt;
+    private ExecutorService executor = Executors.newFixedThreadPool(10);
+    
+    public InstanceCountCallable(String domain, String subDomain, CloudControllerClient client, AppDomainContext appCtxt){
+        this.domain = domain;
+        this.subDomain = subDomain;
+        this.client = client;
+        this.appCtxt = appCtxt;
+    }
+    
+    @Override
+    public Boolean call() throws Exception {
+        log.debug("Computation of instance counts started for domain: " + this.domain +
+            " and sub domain: " + this.subDomain);
+
+        Callable<Integer> worker = new RunningInstanceCountCallable(this.domain, this.subDomain);
+        Future<Integer> runningInstanceCount = executor.submit(worker);
+
+//        worker = new PendingInstanceCountCallable(this.domain, this.subDomain, client);
+//        Future<Integer> pendingInstanceCount = executor.submit(worker);
+
+        int runningInstances = 0, pendingInstances = 0;
+        if (appCtxt != null) {
+
+            try {
+                // get the values of Callables
+                runningInstances = runningInstanceCount.get();
+                pendingInstances = appCtxt.getPendingInstanceCount();
+            } catch (Exception e) {
+                // no need to throw
+                log.error(e.getMessage(), e);
+            }
+
+            appCtxt.setRunningInstanceCount(runningInstances);
+            appCtxt.setPendingInstanceCount(pendingInstances);
+            
+        }
+        return true;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/PendingInstanceCountCallable.java
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diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/PendingInstanceCountCallable.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/PendingInstanceCountCallable.java
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,65 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.callables;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.mediator.autoscale.lbautoscale.clients.CloudControllerClient;
+
+import java.util.concurrent.Callable;
+
+/** Calculate pending instances of each service domain, sub domain combination **/
+public class PendingInstanceCountCallable implements Callable<Integer> {
+
+    private static final Log log = LogFactory.getLog(PendingInstanceCountCallable.class);
+    private String domain;
+    private String subDomain;
+    private CloudControllerClient client;
+    
+    public PendingInstanceCountCallable(String domain, String subDomain, CloudControllerClient client){
+        this.domain = domain;
+        this.subDomain = subDomain;
+        this.client = client;
+    }
+    
+    @Override
+    public Integer call() throws Exception {
+        int pendingInstanceCount = 0;
+
+        try {
+            pendingInstanceCount =
+                client.getPendingInstanceCount(this.domain,
+                    this.subDomain);
+
+        } catch (Exception e) {
+            log.error("Failed to retrieve pending instance count for domain: " +
+                this.domain + " and sub domain: " + this.subDomain, e);
+        }
+
+        log.debug("Pending instance count for domain: " +
+            this.domain +
+            ", sub domain: " +
+            this.subDomain +
+            " is " +
+            pendingInstanceCount);
+
+        return pendingInstanceCount;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/RunningInstanceCountCallable.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/RunningInstanceCountCallable.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/callables/RunningInstanceCountCallable.java
new file mode 100644
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@@ -0,0 +1,68 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.callables;
+
+import org.apache.axis2.clustering.management.GroupManagementAgent;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+
+import java.util.concurrent.Callable;
+
+/** Calculate running instances of each service domain, sub domain combination **/
+public class RunningInstanceCountCallable implements Callable<Integer> {
+
+    private static final Log log = LogFactory.getLog(RunningInstanceCountCallable.class);
+    private String domain;
+    private String subDomain;
+    
+    public RunningInstanceCountCallable(String domain, String subDomain){
+        this.domain = domain;
+        this.subDomain = subDomain;
+    }
+    
+    @Override
+    public Integer call() throws Exception {
+        int runningInstances;
+        // for each sub domain, get the clustering group management agent
+        GroupManagementAgent agent =
+            AutoscalerTaskDSHolder.getInstance().getAgent()
+                .getGroupManagementAgent(this.domain,
+                    this.subDomain);
+
+        // if it isn't null
+        if (agent != null) {
+            // we calculate running instance count for this service domain
+            runningInstances = agent.getMembers().size();
+        } else {
+            // if agent is null, we assume no service instances are running
+            runningInstances = 0;
+        }
+
+        log.debug("Running instance count for domain: " +
+            this.domain +
+                ", sub domain: " +
+                this.subDomain +
+                " is " +
+                runningInstances);
+        
+        return runningInstances;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerClient.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerClient.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerClient.java
new file mode 100644
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@@ -0,0 +1,66 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.clients;
+
+/**
+ * Each Implementation which provides access to Cloud Controller, should implement this interface.
+ */
+public abstract class CloudControllerClient {
+
+    /**
+     * Initializes the client.
+     */
+    public abstract void init();
+    
+    /**
+     * Should start an instance.
+     * @param domainName clustering domain.
+     * @param subDomainName clustering sub domain.
+     * @return Public IP of the spawned instance.
+     * @throws Exception 
+     */
+    public abstract String startInstance(String domainName, String subDomainName) throws Exception;
+    
+    /**
+     * Terminates an instance belongs to the given cluster.
+     * @param domainName clustering domain.
+     * @param subDomainName clustering sub domain.
+     * @return whether the termination is successful or not.
+     * @throws Exception
+     */
+    public abstract boolean terminateInstance(String domainName, String subDomainName) throws Exception;
+    
+    /**
+     * Terminates lastly spawned instance of the given cluster.
+     * @param domainName clustering domain.
+     * @param subDomainName clustering sub domain.
+     * @return whether the termination is successful or not.
+     * @throws Exception
+     */
+    public abstract boolean terminateLastlySpawnedInstance(String domainName, String subDomainName) throws Exception;
+    
+    /**
+     * Return pending instance count of the given cluster.
+     * @param domainName clustering domain.
+     * @param subDomainName clustering sub domain.
+     * @return pending instance count.
+     * @throws Exception
+     */
+    public abstract int getPendingInstanceCount(String domainName, String subDomainName) throws Exception;
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerOsgiClient.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerOsgiClient.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerOsgiClient.java
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@@ -0,0 +1,82 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.clients;
+
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.cloud.controller.interfaces.CloudControllerService;
+
+/**
+ * This is the client class this calls Autoscaler service.
+ */
+public class CloudControllerOsgiClient extends CloudControllerClient {
+
+    private CloudControllerService cloudControllerService;
+
+    private static final Log log = LogFactory.getLog(CloudControllerOsgiClient.class);
+
+    // public CloudControllerStubClient(String epr) throws AxisFault {
+    //
+    // try {
+    //
+    // stub = new CloudControllerServiceStub(epr);
+    // stub._getServiceClient().getOptions().setTimeOutInMilliSeconds(90000);
+    //
+    // } catch (AxisFault axisFault) {
+    // String msg =
+    // "Failed to initiate AutoscalerService client. " + axisFault.getMessage();
+    // log.error(msg, axisFault);
+    // throw new AxisFault(msg, axisFault);
+    // }
+    // }
+
+    // public boolean init(boolean isSpi) throws Exception {
+    //
+    // return stub.initAutoscaler(isSpi);
+    // }
+
+    public String startInstance(String domainName, String subDomainName) throws Exception {
+
+        return cloudControllerService.startInstance(domainName, subDomainName);
+    }
+
+    public boolean terminateInstance(String domainName, String subDomainName) throws Exception {
+
+        return cloudControllerService.terminateInstance(domainName, subDomainName);
+    }
+
+    public boolean
+        terminateLastlySpawnedInstance(String domainName, String subDomainName) throws Exception {
+
+        return cloudControllerService.terminateLastlySpawnedInstance(domainName, subDomainName);
+    }
+
+    public int getPendingInstanceCount(String domainName, String subDomainName) throws Exception {
+
+        return cloudControllerService.getPendingInstanceCount(domainName, subDomainName);
+    }
+
+    @Override
+    public void init() {
+
+        cloudControllerService = AutoscalerTaskDSHolder.getInstance().getCloudControllerService();
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerStubClient.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerStubClient.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/clients/CloudControllerStubClient.java
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,93 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.clients;
+
+import org.apache.axis2.AxisFault;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.cloud.controller.stub.CloudControllerServiceStub;
+
+/**
+ * This is the client class this calls Autoscaler service.
+ */
+public class CloudControllerStubClient extends CloudControllerClient {
+
+    private CloudControllerServiceStub stub;
+    private static final String CLOUD_CONTROLLER_EPR = AutoscalerTaskDSHolder.getInstance().getLoadBalancerConfig().getAutoscalerServiceEpr();
+
+    private static final Log log = LogFactory.getLog(CloudControllerStubClient.class);
+
+    // public CloudControllerStubClient(String epr) throws AxisFault {
+    //
+    // try {
+    //
+    // stub = new CloudControllerServiceStub(epr);
+    // stub._getServiceClient().getOptions().setTimeOutInMilliSeconds(90000);
+    //
+    // } catch (AxisFault axisFault) {
+    // String msg =
+    // "Failed to initiate AutoscalerService client. " + axisFault.getMessage();
+    // log.error(msg, axisFault);
+    // throw new AxisFault(msg, axisFault);
+    // }
+    // }
+
+    // public boolean init(boolean isSpi) throws Exception {
+    //
+    // return stub.initAutoscaler(isSpi);
+    // }
+
+    public String startInstance(String domainName, String subDomainName) throws Exception {
+
+        return stub.startInstance(domainName, subDomainName);
+    }
+
+    public boolean terminateInstance(String domainName, String subDomainName) throws Exception {
+
+        return stub.terminateInstance(domainName, subDomainName);
+    }
+
+    public boolean
+        terminateLastlySpawnedInstance(String domainName, String subDomainName) throws Exception {
+
+        return stub.terminateLastlySpawnedInstance(domainName, subDomainName);
+    }
+
+    public int getPendingInstanceCount(String domainName, String subDomainName) throws Exception {
+
+        return stub.getPendingInstanceCount(domainName, subDomainName);
+    }
+
+    @Override
+    public void init() {
+
+        try {
+
+            stub = new CloudControllerServiceStub(CLOUD_CONTROLLER_EPR);
+            stub._getServiceClient().getOptions().setTimeOutInMilliSeconds(300000);
+
+        } catch (AxisFault axisFault) {
+            String msg = "Failed to initiate AutoscalerService client. " + axisFault.getMessage();
+            log.error(msg, axisFault);
+            throw new RuntimeException(msg, axisFault);
+        }
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/AppDomainContext.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/AppDomainContext.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/AppDomainContext.java
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@@ -0,0 +1,170 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.context;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.lb.common.conf.LoadBalancerConfiguration;
+
+
+/**
+ * Contextual information related to autoscaling for a particular clustering domain
+ */
+public class AppDomainContext extends LoadBalancerContext{
+
+    private static final long serialVersionUID = 6582721801663800609L;
+
+    private static final Log log = LogFactory.getLog(AppDomainContext.class);
+
+    /**
+     * Request tokens of requests in flight
+     * <p/>
+     * Key - request token ID, Value - message received time
+     */
+    private Map<String, Long> requestTokens = new ConcurrentHashMap<String, Long>();
+    private List<Integer> requestTokenListLengths;
+    private LoadBalancerConfiguration.ServiceConfiguration serviceConfig;
+
+    public AppDomainContext(LoadBalancerConfiguration.ServiceConfiguration serviceConfig) {
+        this.serviceConfig = serviceConfig;
+        requestTokenListLengths = new Vector<Integer>(serviceConfig.getRoundsToAverage());
+    }
+
+    public LoadBalancerConfiguration.ServiceConfiguration getServiceConfig() {
+        return serviceConfig;
+    }
+
+    /**
+     * If there is insufficient number of messages we cannot make a scaling decision.
+     *
+     * @return true - if a scaling decision can be made
+     */
+    public boolean canMakeScalingDecision() {
+        return requestTokenListLengths.size() >= serviceConfig.getRoundsToAverage();
+    }
+
+    public void addRequestToken(String tokenId) {
+        requestTokens.put(tokenId, System.currentTimeMillis());
+        if (log.isDebugEnabled()) {
+            log.debug("Request Tokens Added : "+requestTokens.size());
+        }
+    }
+
+    public void removeRequestToken(String tokenId) {
+        requestTokens.remove(tokenId);
+    }
+
+//    public int getRunningInstanceCount() {
+//        return super.getRunningInstanceCount();
+//    }
+
+    /**
+     * This will set the running instance count for this app domain
+     * and also will return the difference of current running instance count and previous count.
+     * @param runningInstanceCount current running instance count
+     * @return difference of current running instance count and previous count.
+     */
+//    public int setRunningInstanceCount(int runningInstanceCount) {
+//        int diff = 0;
+//        
+//        if(this.runningInstanceCount < runningInstanceCount){
+//            diff = runningInstanceCount - this.runningInstanceCount;
+//        }
+//        
+//        this.runningInstanceCount = runningInstanceCount;
+//        
+//        return diff;
+//    }
+
+    public void expireRequestTokens() {
+        for (Map.Entry<String, Long> entry : requestTokens.entrySet()) {
+            if (System.currentTimeMillis() - entry.getValue() >= serviceConfig.getMessageExpiryTime()) {
+                requestTokens.remove(entry.getKey());
+                if (log.isDebugEnabled()) {
+                    log.debug("Request Tokens Expired : " + requestTokens.get(entry.getKey()));
+                }
+            }
+        }
+    }
+
+    public void recordRequestTokenListLength() {
+        if (requestTokenListLengths.size() >= serviceConfig.getRoundsToAverage()) {
+            int count = requestTokenListLengths.remove(0);
+            if (log.isDebugEnabled()) {
+                log.debug("Request Tokens Removed : " + count);
+            }
+        }
+        if (log.isDebugEnabled()) {
+            log.debug("Request Tokens Added : " + requestTokens.size());
+        }
+        requestTokenListLengths.add(requestTokens.size());
+    }
+
+
+//    public synchronized int getPendingInstances() {
+//        return pendingInstances;
+//    }
+
+//    public synchronized void incrementPendingInstances() {
+//        this.pendingInstances++;
+//    }
+
+//    public synchronized void decrementPendingInstancesIfNotZero(int diff) {
+//        
+//        while (diff > 0 && this.pendingInstances > 0 ){
+//            this.pendingInstances--;
+//            diff--;
+//        }
+//        
+//    }
+    
+//    public synchronized int getInstances() {
+//        return runningInstanceCount + pendingInstances;
+//    }
+
+    /**
+     * Get the average requests in flight, averaged over the number of  of observations rounds
+     *
+     * @return number of average requests in flight. -1 if there no requests were received
+     */
+    public long getAverageRequestsInFlight() {
+        long total = 0;
+        for (Integer messageQueueLength : requestTokenListLengths) {
+            total += messageQueueLength;
+        }
+        int size = requestTokenListLengths.size();
+        if (size == 0) {
+            return -1; // -1 means that no requests have been received
+        }
+        
+        if (log.isDebugEnabled()) {
+            log.debug("Total Tokens : "+total+ " : Size: "+size);
+        }
+        return (long) total / size;
+    }
+
+
+//    public synchronized void resetRunningPendingInstances() {
+//        pendingInstances = 0;
+//        runningInstanceCount = 0;
+//    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/LoadBalancerContext.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/LoadBalancerContext.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/context/LoadBalancerContext.java
new file mode 100644
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@@ -0,0 +1,104 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.context;
+
+import java.io.Serializable;
+
+/**
+ * Contextual information related to autoscaling for a particular domain
+ */
+public class LoadBalancerContext implements Serializable{
+
+    private static final long serialVersionUID = -2022110665957598060L;
+    private int runningInstances;
+    private int pendingInstances;
+    private int terminatingInstances;
+    
+    public synchronized int getTerminatingInstanceCount() {
+        return terminatingInstances;
+    }
+    
+    public synchronized int getRunningInstanceCount() {
+        return runningInstances;
+    }
+    
+    public synchronized int getPendingInstanceCount() {
+        return pendingInstances;
+    }
+
+    /**
+     * This will set the running instance count for a domain
+     * and also will return the difference of current running instance count and previous count.
+     * @param runningInstanceCount current running instance count
+     * @return difference of current running instance count and previous count.
+     */
+    public synchronized int setRunningInstanceCount(int count) {
+        int diff = 0;
+
+        if (this.runningInstances < count) {
+            diff = count - this.runningInstances;
+        }
+
+        this.runningInstances = count;
+
+        return diff;
+    }
+
+    public synchronized int getInstances() {
+        return runningInstances + pendingInstances;
+    }
+    
+    public synchronized void setPendingInstanceCount(int count) {
+        
+        this.pendingInstances = count;
+    }
+    
+    public synchronized void setTerminatingInstanceCount(int count) {
+        
+        this.terminatingInstances = count;
+    }
+
+    public synchronized void incrementPendingInstances(int diff) {
+
+        this.pendingInstances += diff;
+    }
+    
+    public synchronized void incrementTerminatingInstances(int diff) {
+
+        this.terminatingInstances += diff;
+    }
+    
+    public synchronized void decrementPendingInstancesIfNotZero(int diff) {
+
+        while (diff > 0 && this.pendingInstances > 0) {
+            this.pendingInstances--;
+            diff--;
+        }
+
+    }
+    
+    public synchronized void decrementTerminatingInstancesIfNotZero(int diff) {
+
+        while (diff > 0 && this.terminatingInstances > 0) {
+            this.terminatingInstances--;
+            diff--;
+        }
+
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/AutoscalerTaskServiceComponent.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/AutoscalerTaskServiceComponent.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/AutoscalerTaskServiceComponent.java
new file mode 100644
index 0000000..41811eb
--- /dev/null
+++ b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/AutoscalerTaskServiceComponent.java
@@ -0,0 +1,325 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.internal;
+
+import org.apache.axis2.context.ConfigurationContext;
+import org.apache.axis2.description.Parameter;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.lb.common.conf.LoadBalancerConfiguration;
+import org.apache.stratos.lb.common.service.LoadBalancerConfigurationService;
+import org.apache.stratos.mediator.autoscale.lbautoscale.mediators.AutoscaleInMediator;
+import org.apache.stratos.mediator.autoscale.lbautoscale.mediators.AutoscaleOutMediator;
+import org.apache.stratos.mediator.autoscale.lbautoscale.task.*;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+import org.apache.synapse.ManagedLifecycle;
+import org.apache.synapse.Mediator;
+import org.apache.synapse.SynapseConstants;
+import org.apache.synapse.SynapseException;
+import org.apache.synapse.core.SynapseEnvironment;
+import org.apache.synapse.mediators.base.SequenceMediator;
+import org.apache.synapse.mediators.filters.InMediator;
+import org.apache.synapse.mediators.filters.OutMediator;
+import org.apache.synapse.task.Task;
+import org.apache.synapse.task.TaskConstants;
+import org.apache.synapse.task.TaskDescription;
+import org.apache.synapse.task.TaskScheduler;
+import org.apache.synapse.task.service.TaskManagementService;
+import org.osgi.framework.BundleContext;
+import org.osgi.service.component.ComponentContext;
+import org.quartz.JobBuilder;
+import org.quartz.JobDetail;
+import org.wso2.carbon.registry.core.exceptions.RegistryException;
+import org.wso2.carbon.registry.core.service.RegistryService;
+import org.apache.stratos.cloud.controller.interfaces.CloudControllerService;
+import org.wso2.carbon.user.core.service.RealmService;
+import org.wso2.carbon.utils.Axis2ConfigurationContextObserver;
+import org.wso2.carbon.utils.ConfigurationContextService;
+
+import java.util.Date;
+import java.util.Map;
+
+/**
+ * @scr.component name="autoscaler.task.component" immediate="true"
+ * @scr.reference name="carbon.core.configurationContextService"
+ * interface="org.wso2.carbon.utils.ConfigurationContextService"
+ * cardinality="1..1" policy="dynamic"
+ * bind="setConfigurationContextService" unbind="unsetConfigurationContextService"
+ * @scr.reference name="user.realmservice.default"
+ * interface="org.wso2.carbon.user.core.service.RealmService"
+ * cardinality="1..1" policy="dynamic" bind="setRealmService"
+ * unbind="unsetRealmService"
+ * @scr.reference name="org.apache.stratos.lb.common"
+ * interface="org.apache.stratos.lb.common.service.LoadBalancerConfigurationService"
+ * cardinality="1..1" policy="dynamic" bind="setLoadBalancerConfigurationService"
+ * unbind="unsetLoadBalancerConfigurationService"
+ * @scr.reference name="registry.service"
+ * interface="org.wso2.carbon.registry.core.service.RegistryService"
+ * cardinality="1..1" policy="dynamic"
+ * bind="setRegistryService" unbind="unsetRegistryService"
+ * @scr.reference name="org.apache.stratos.cloud.controller"
+ * interface="org.apache.stratos.cloud.controller.interfaces.CloudControllerService"
+ * cardinality="1..1" policy="dynamic" bind="setCloudControllerService"
+ * unbind="unsetCloudControllerService"
+ */
+public class AutoscalerTaskServiceComponent {
+
+    private static final Log log = LogFactory.getLog(AutoscalerTaskServiceComponent.class);
+    private ConfigurationContext configurationContext = null;
+
+    protected void activate(ComponentContext context) {
+    	
+    	try{
+
+        // read config file
+//        String configURL = System.getProperty(AutoscaleConstants.LOAD_BALANCER_CONFIG);
+//        LoadBalancerConfiguration lbConfig = new LoadBalancerConfiguration();
+//        lbConfig.init(configURL);
+        
+        if(configurationContext == null){
+            String msg = "Configuration context is null. Autoscaler task activation failed.";
+            log.fatal(msg);
+            throw new RuntimeException(msg);
+        }
+
+        // load synapse environment
+        Parameter synEnv =
+                configurationContext.getAxisConfiguration().getParameter(SynapseConstants.SYNAPSE_ENV);
+
+        if (synEnv == null || synEnv.getValue() == null ||
+                !(synEnv.getValue() instanceof SynapseEnvironment)) {
+
+            String message = "Unable to initialize the Synapse Configuration : Can not find the ";
+            log.fatal(message + "Synapse Environment");
+            throw new SynapseException(message + "Synapse Environment");
+        }
+
+        SynapseEnvironment synapseEnv = (SynapseEnvironment) synEnv.getValue();
+
+        /** Initializing autoscaleIn and autoscaleOut Mediators.**/
+
+        LoadBalancerConfiguration lbConfig = AutoscalerTaskDSHolder.getInstance().getWholeLoadBalancerConfig();
+        // check whether autoscaling is enabled
+        if (lbConfig.getLoadBalancerConfig().isAutoscaleEnabled()) {
+
+            // get the main sequence mediator
+            SequenceMediator mainSequence =
+                    (SequenceMediator) synapseEnv.getSynapseConfiguration().getSequence("main");
+
+            // iterate through its child mediators
+            for (Mediator child : mainSequence.getList()) {
+
+                // find the InMediator
+                if (child instanceof InMediator) {
+                    InMediator inSequence = (InMediator) child;
+
+                    // if the first child of InMediator isn't an AutoscaleInMediator
+                    if (!(inSequence.getList().get(0) instanceof AutoscaleInMediator)) {
+
+                        // we gonna add it!
+                        inSequence.getList().add(0, new AutoscaleInMediator());
+                        if (log.isDebugEnabled()) {
+                            log.debug("Added Mediator: " + inSequence.getChild(0) + "" +
+                                    " to InMediator. Number of child mediators in InMediator" + " is " +
+                                    inSequence.getList().size() + ".");
+                        }
+                    }
+
+                }
+
+                // find the OutMediator
+                if (child instanceof OutMediator) {
+
+                    OutMediator outSequence = (OutMediator) child;
+
+                    // if the first child of OutMediator isn't an AutoscaleOutMediator
+                    if (!(outSequence.getList().get(0) instanceof AutoscaleOutMediator)) {
+
+                        // we gonna add it!
+                        outSequence.getList().add(0, new AutoscaleOutMediator());
+
+                        if (log.isDebugEnabled()) {
+                            log.debug("Added Mediator: " + outSequence.getChild(0) + "" +
+                                    " to OutMediator. Number of child mediators in OutMediator" +
+                                    " is " + outSequence.getList().size() + ".");
+                        }
+
+                    }
+                }
+            }
+
+            /** Initializing Autoscaler Task **/
+
+            BundleContext bundleContext = context.getBundleContext();
+            if (log.isDebugEnabled()) {
+                log.debug("Initiating Autoscaler task service component");
+            }
+
+            if (bundleContext.getServiceReference(TaskManagementService.class.getName()) != null) {
+                bundleContext.registerService(TaskManagementService.class.getName(),
+                        new AutoscalerTaskMgmtAdminService(), null);
+            }
+
+
+            AutoscalerTaskInitializer listener = new AutoscalerTaskInitializer();
+
+            if (bundleContext.getServiceReference(Axis2ConfigurationContextObserver.class.getName()) != null) {
+                bundleContext.registerService(Axis2ConfigurationContextObserver.class.getName(),
+                        listener, null);
+            }
+
+            if (configurationContext != null) {
+                TaskScheduler scheduler =
+                        (TaskScheduler) configurationContext.getProperty(AutoscalerTaskInitializer.CARBON_TASK_SCHEDULER);
+                if (scheduler == null) {
+                    scheduler = new TaskScheduler(TaskConstants.TASK_SCHEDULER);
+                    scheduler.init(null);
+                    configurationContext.setProperty(AutoscalerTaskInitializer.CARBON_TASK_SCHEDULER,
+                            scheduler);
+                } else if (!scheduler.isInitialized()) {
+                    scheduler.init(null);
+                }
+            }
+            
+            String autoscalerClass = lbConfig.getLoadBalancerConfig().getAutoscalerTaskClass();
+            Task task;
+            if (autoscalerClass != null) {
+                try {
+                    task = (Task) Class.forName(autoscalerClass).newInstance();
+                } catch (Exception e) {
+                    String msg = "Cannot instantiate Autoscaling Task. Class: " + autoscalerClass
+                    		+". It should implement 'org.apache.synapse.task.Task' and "
+                    		+"'org.apache.synapse.ManagedLifecycle' interfaces.";
+                    log.error(msg, e);
+                    throw new RuntimeException(msg, e);
+                }
+            } else {
+                task = new ServiceRequestsInFlightAutoscaler();
+            }
+
+//            ServiceRequestsInFlightAutoscaler autoscalerTask =
+//                    new ServiceRequestsInFlightAutoscaler();
+
+            ((ManagedLifecycle) task).init(synapseEnv);
+
+            // specify scheduler task details
+            JobBuilder jobBuilder = JobBuilder.newJob(AutoscalingJob.class)
+                .withIdentity("autoscalerJob");
+            JobDetail job = jobBuilder.build();
+
+            Map<String, Object> dataMap = job.getJobDataMap();
+            dataMap.put(AutoscalingJob.AUTOSCALER_TASK, task);
+            dataMap.put(AutoscalingJob.SYNAPSE_ENVI, synapseEnv);
+
+            final TaskDescription taskDescription = new TaskDescription();
+            taskDescription.setTaskClass(ServiceRequestsInFlightAutoscaler.class.getName());
+            taskDescription.setName("autoscaler");
+            //taskDescription.setCount(SimpleTrigger.REPEAT_INDEFINITELY);
+
+            int interval = AutoscalerTaskDSHolder.getInstance().getLoadBalancerConfig().getAutoscalerTaskInterval();
+            taskDescription.setInterval(interval);
+            taskDescription.setStartTime(new Date(System.currentTimeMillis() + (interval*2)));
+
+            TaskSchedulingManager scheduler = new TaskSchedulingManager();
+            scheduler.scheduleTask(taskDescription, dataMap, configurationContext);
+
+
+        } else {
+
+            log.info("Autoscaling is disabled.");
+        }
+    	} catch (Throwable e) {
+            log.error("Failed to activate Autoscaler Task Service Component. ", e);
+        }
+    }
+
+
+    protected void deactivate(ComponentContext ctx) {
+        AutoscalerTaskDSHolder.getInstance().setConfigurationContextService(null);
+        if (log.isDebugEnabled()) {
+            log.debug("Autoscaler task bundle is deactivated");
+        }
+    }
+
+	protected void setCloudControllerService(CloudControllerService cc) {
+        AutoscalerTaskDSHolder.getInstance().setCloudControllerService(cc);
+    }
+    
+    protected void unsetCloudControllerService(CloudControllerService cc) {
+        AutoscalerTaskDSHolder.getInstance().setCloudControllerService(null);
+    }
+
+    protected void setConfigurationContextService(ConfigurationContextService context) {
+        if (log.isDebugEnabled()) {
+            log.debug("ConfigurationContextService bound to the Autoscaler task initialization process");
+        }
+        this.configurationContext = context.getServerConfigContext();
+        AutoscalerTaskDSHolder.getInstance().setConfigurationContextService(context);
+    }
+
+    protected void unsetConfigurationContextService(ConfigurationContextService configurationContextService) {
+        if (log.isDebugEnabled()) {
+            log.debug("ConfigurationContextService unbound from the Autoscaler task");
+        }
+        this.configurationContext = null;
+        AutoscalerTaskDSHolder.getInstance().setConfigurationContextService(null);
+    }
+
+    protected void setRealmService(RealmService realmService) {
+        if (log.isDebugEnabled()) {
+            log.debug("Bound realm service from the Autoscaler task");
+        }
+        AutoscalerTaskDSHolder.getInstance().setRealmService(realmService);
+    }
+
+    protected void unsetRealmService(RealmService realmService) {
+        if (log.isDebugEnabled()) {
+            log.debug("Unbound realm service from the Autoscaler task");
+        }
+        AutoscalerTaskDSHolder.getInstance().setRealmService(null);
+    }
+    
+    protected void setLoadBalancerConfigurationService(LoadBalancerConfigurationService lbConfigSer){
+        AutoscalerTaskDSHolder.getInstance().setLbConfigService(lbConfigSer);
+    }
+    
+    protected void unsetLoadBalancerConfigurationService(LoadBalancerConfigurationService lbConfigSer){
+        AutoscalerTaskDSHolder.getInstance().setLbConfigService(null);
+    }
+    
+    protected void setRegistryService(RegistryService regService) {
+        if (log.isDebugEnabled()) {
+            log.debug("RegistryService bound to the endpoint component");
+        }
+        try {
+            AutoscalerTaskDSHolder.getInstance().setConfigRegistry(regService.getConfigSystemRegistry());
+            AutoscalerTaskDSHolder.getInstance().setGovernanceRegistry(regService.getGovernanceSystemRegistry());
+        } catch (RegistryException e) {
+            log.error("Couldn't retrieve the registry from the registry service");
+        }
+    }
+
+    protected void unsetRegistryService(RegistryService regService) {
+        if (log.isDebugEnabled()) {
+            log.debug("RegistryService unbound from the endpoint component");
+        }
+        AutoscalerTaskDSHolder.getInstance().setConfigRegistry(null);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/RegistryManager.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/RegistryManager.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/RegistryManager.java
new file mode 100644
index 0000000..0f5a03d
--- /dev/null
+++ b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/internal/RegistryManager.java
@@ -0,0 +1,54 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.internal;
+
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.stratos.lb.common.util.DomainMapping;
+import org.wso2.carbon.registry.core.Resource;
+import org.wso2.carbon.registry.core.exceptions.RegistryException;
+import org.wso2.carbon.registry.core.session.UserRegistry;
+
+public class RegistryManager {
+    UserRegistry governanceRegistry = AutoscalerTaskDSHolder.getInstance().getGovernanceRegistry();
+    private static final Log log = LogFactory.getLog(RegistryManager.class);
+    /**
+     *
+     */
+    private Resource resource = null;
+    public static final String HOST_INFO = "hostinfo/";
+    public static final String ACTUAL_HOST = "actual.host";
+
+    public DomainMapping getMapping(String hostName) {
+        DomainMapping domainMapping;
+        try {
+            if (governanceRegistry.resourceExists(HOST_INFO + hostName)) {
+                resource = governanceRegistry.get(HOST_INFO + hostName);
+                domainMapping = new DomainMapping(hostName);
+                domainMapping.setActualHost(resource.getProperty(ACTUAL_HOST));
+                return domainMapping;
+            }
+        } catch (RegistryException e) {
+            log.info("Error while getting registry resource");
+            throw new RuntimeException(e);
+        }
+        return null;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleInMediator.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleInMediator.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleInMediator.java
new file mode 100644
index 0000000..6ec1da3
--- /dev/null
+++ b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleInMediator.java
@@ -0,0 +1,174 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.mediators;
+
+import org.apache.axis2.context.ConfigurationContext;
+import org.apache.stratos.mediator.autoscale.lbautoscale.context.AppDomainContext;
+import org.apache.stratos.mediator.autoscale.lbautoscale.internal.RegistryManager;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscaleConstants;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscaleUtil;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscalerTaskDSHolder;
+import org.apache.http.protocol.HTTP;
+import org.apache.synapse.ManagedLifecycle;
+import org.apache.synapse.MessageContext;
+import org.apache.synapse.core.SynapseEnvironment;
+import org.apache.synapse.core.axis2.Axis2MessageContext;
+import org.apache.synapse.mediators.AbstractMediator;
+import org.apache.stratos.lb.common.conf.LoadBalancerConfiguration;
+import org.apache.stratos.lb.common.conf.util.HostContext;
+import org.apache.stratos.lb.common.cache.URLMappingCache;
+import org.apache.stratos.lb.common.util.DomainMapping;
+
+import java.util.Map;
+
+/**
+ * This Synapse mediator generates a token per request received. These tokens are used for tracking
+ * the number of requests in flight. Once a response is received, the relevant token will be removed
+ * by the {@link AutoscaleOutMediator}
+ *
+ * @see AutoscaleOutMediator
+ */
+public class AutoscaleInMediator extends AbstractMediator implements ManagedLifecycle {
+
+    private LoadBalancerConfiguration lbConfig;
+    private Map<String, HostContext> hostCtxts;
+    /**
+     * keep the size of cache which used to keep hostNames of url mapping.
+     */
+    private URLMappingCache mappingCache;
+    private RegistryManager registryManager;
+    private int sizeOfCache;
+
+    public AutoscaleInMediator() {
+
+        this.lbConfig = AutoscalerTaskDSHolder.getInstance().getWholeLoadBalancerConfig();
+        hostCtxts = lbConfig.getHostContextMap();
+        sizeOfCache = lbConfig.getLoadBalancerConfig().getSizeOfCache();
+        mappingCache = URLMappingCache.getInstance(sizeOfCache);
+    }
+
+    public boolean mediate(MessageContext synCtx) {
+
+        if (log.isDebugEnabled()) {
+            log.debug("Mediation started .......... " + AutoscaleInMediator.class.getName());
+
+        }
+
+        ConfigurationContext configCtx =
+                                         ((Axis2MessageContext) synCtx).getAxis2MessageContext()
+                                                                       .getConfigurationContext();
+        String uuid = org.apache.axiom.util.UIDGenerator.generateUID();
+        synCtx.setProperty(AutoscaleConstants.REQUEST_ID, uuid);
+
+        Map<String, Map<String, ?>> appDomainContexts =
+                                                                       AutoscaleUtil.getAppDomainContexts(configCtx,
+                                                                               lbConfig);
+        org.apache.axis2.context.MessageContext axis2MessageContext =
+                ((Axis2MessageContext) synCtx).getAxis2MessageContext();
+        Map<String, String> transportHeaders = (Map<String, String>) axis2MessageContext.
+                getProperty(org.apache.axis2.context.MessageContext.TRANSPORT_HEADERS);
+        String targetHost = transportHeaders.get(HTTP.TARGET_HOST);
+        
+        String toAddress = synCtx.getTo().getAddress();
+        if (targetHost.contains(":")) {
+            targetHost = targetHost.substring(0, targetHost.indexOf(':'));
+        }
+
+        int tenantId = AutoscaleUtil.getTenantId(synCtx.getTo().toString());
+
+        String domain = null, subDomain = null;
+        
+        log.debug("************ Target Host: "+targetHost + " -- Tenant id : "+tenantId);
+
+        HostContext ctxt = hostCtxts.get(targetHost);
+        
+        if (ctxt == null) {
+
+            DomainMapping domainMapping = mappingCache.getMapping(targetHost);
+            if (domainMapping == null) {
+                registryManager = new RegistryManager();
+                domainMapping = registryManager.getMapping(targetHost);
+                mappingCache.addValidMapping(targetHost, domainMapping);
+            }
+            if (domainMapping != null) {
+
+                String actualHost = domainMapping.getActualHost();
+
+                // get the HostContext from the actual host name in the case of domain 
+                // mapping.
+                ctxt = hostCtxts.get(actualHost);
+
+            }
+        }
+
+        if (ctxt == null) {
+            log.debug("Host Context is null.");
+        	// we don't need to do anything 
+        	return true;
+        }
+
+
+        // gets the corresponding domain
+        domain = ctxt.getDomainFromTenantId(tenantId);
+        synCtx.setProperty(AutoscaleConstants.TARGET_DOMAIN, domain);
+
+        // gets the corresponding sub domain
+        subDomain = ctxt.getSubDomainFromTenantId(tenantId);
+        synCtx.setProperty(AutoscaleConstants.TARGET_SUB_DOMAIN, subDomain);
+
+        if (appDomainContexts.get(domain) == null) {
+            // if we do not find a correct context, we just ignore
+            log.debug("AppDomainContext not found for domain " + domain);
+
+        } else {
+            AppDomainContext appDomainContext = (AppDomainContext) appDomainContexts.get(domain).get(subDomain);
+
+            if (appDomainContext != null) {
+                appDomainContext.addRequestToken(uuid);
+                System.setProperty(AutoscaleConstants.IS_TOUCHED, "true");
+
+            } else {
+                // if we do not find a correct context, we just ignore
+                log.debug("AppDomainContext not found for sub domain: " + subDomain +
+                          " of domain: " + domain);
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public void destroy() {
+
+        log.info("Mediator destroyed! " + AutoscaleInMediator.class.getName());
+    }
+
+    @Override
+    public void init(SynapseEnvironment arg0) {
+
+        if (log.isDebugEnabled()) {
+            log.debug("Mediator initialized! " + AutoscaleInMediator.class.getName());
+        }
+    }
+    
+    private void throwException(String msg){
+        log.error(msg);
+        throw new RuntimeException(msg);
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-stratos/blob/ac065d73/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleOutMediator.java
----------------------------------------------------------------------
diff --git a/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleOutMediator.java b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleOutMediator.java
new file mode 100644
index 0000000..3640c08
--- /dev/null
+++ b/components/org.apache.stratos.mediator.autoscale/src/main/java/org/apache/stratos/mediator/autoscale/lbautoscale/mediators/AutoscaleOutMediator.java
@@ -0,0 +1,78 @@
+/**
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+
+ *  http://www.apache.org/licenses/LICENSE-2.0
+
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.stratos.mediator.autoscale.lbautoscale.mediators;
+
+import org.apache.axis2.context.ConfigurationContext;
+import org.apache.stratos.mediator.autoscale.lbautoscale.util.AutoscaleConstants;
+import org.apache.synapse.ManagedLifecycle;
+import org.apache.synapse.MessageContext;
+import org.apache.synapse.core.SynapseEnvironment;
+import org.apache.synapse.core.axis2.Axis2MessageContext;
+import org.apache.synapse.mediators.AbstractMediator;
+import org.apache.stratos.mediator.autoscale.lbautoscale.context.AppDomainContext;
+
+import java.util.Map;
+
+/**
+ * This Synapse mediator removes the request token generated by the {@link AutoscaleInMediator}
+ * 
+ * @see AutoscaleInMediator
+ */
+public class AutoscaleOutMediator extends AbstractMediator implements ManagedLifecycle {
+
+    public boolean mediate(MessageContext synCtx) {
+
+        log.debug("Mediation started ....... " + AutoscaleOutMediator.class.getName());
+
+        ConfigurationContext configCtx =
+            ((Axis2MessageContext) synCtx).getAxis2MessageContext().getConfigurationContext();
+
+        String domain = (String) synCtx.getProperty(AutoscaleConstants.TARGET_DOMAIN);
+        // gets the corresponding sub domain
+        String subDomain = (String) synCtx.getProperty(AutoscaleConstants.TARGET_SUB_DOMAIN);
+        
+        String tokenId = (String) synCtx.getProperty(AutoscaleConstants.REQUEST_ID);
+        @SuppressWarnings("unchecked")
+        Map<String, Map<String, AppDomainContext>> appDomainContexts =
+            (Map<String, Map<String, AppDomainContext>>) configCtx.getPropertyNonReplicable(AutoscaleConstants.APP_DOMAIN_CONTEXTS);
+        AppDomainContext appDomainContext = null ;
+        
+        if(appDomainContexts.get(domain) != null){
+        	appDomainContext = appDomainContexts.get(domain).get(subDomain);
+        }
+        
+        if (appDomainContext != null) {
+            appDomainContext.removeRequestToken(tokenId);
+            System.setProperty(AutoscaleConstants.IS_TOUCHED, "true");
+        } else {
+            log.debug("AppDomainContext not found for domain " + domain+" and sub domain : "+subDomain);
+        }
+        return true;
+    }
+
+    @Override
+    public void destroy() {
+        log.debug("Autoscale out mediator destroyed...");
+    }
+
+    @Override
+    public void init(SynapseEnvironment arg0) {
+        log.debug("Autoscale out mediator started...");
+    }
+}