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Posted to commits@jackrabbit.apache.org by th...@apache.org on 2011/07/05 17:30:53 UTC
svn commit: r1143104 - in
/jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk:
MicroKernelImpl.java api/MicroKernel.java mem/MemoryKernelImpl.java
util/CommitGate.java
Author: thomasm
Date: Tue Jul 5 15:30:52 2011
New Revision: 1143104
URL: http://svn.apache.org/viewvc?rev=1143104&view=rev
Log:
New method waitForCommit to avoid polling delays.
Added:
jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/util/CommitGate.java
Modified:
jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/MicroKernelImpl.java
jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/api/MicroKernel.java
jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/mem/MemoryKernelImpl.java
Modified: jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/MicroKernelImpl.java
URL: http://svn.apache.org/viewvc/jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/MicroKernelImpl.java?rev=1143104&r1=1143103&r2=1143104&view=diff
==============================================================================
--- jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/MicroKernelImpl.java (original)
+++ jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/MicroKernelImpl.java Tue Jul 5 15:30:52 2011
@@ -25,6 +25,7 @@ import org.apache.jackrabbit.mk.store.Co
import org.apache.jackrabbit.mk.store.Node;
import org.apache.jackrabbit.mk.store.NodeDiffHandler;
import org.apache.jackrabbit.mk.store.NodeUtils;
+import org.apache.jackrabbit.mk.util.CommitGate;
import org.apache.jackrabbit.mk.util.PathUtils;
import java.io.InputStream;
@@ -41,6 +42,7 @@ import java.util.Map;
public class MicroKernelImpl implements MicroKernel {
protected Repository rep;
+ private final CommitGate gate = new CommitGate();
public MicroKernelImpl(String homeDir) throws MicroKernelException {
init(homeDir);
@@ -56,6 +58,7 @@ public class MicroKernelImpl implements
}
public void dispose() {
+ gate.commit("end");
if (rep != null) {
try {
rep.shutDown();
@@ -112,6 +115,10 @@ public class MicroKernelImpl implements
return buff.endArray().toString();
}
+ public String waitForCommit(String oldHeadRevision, long maxWaitMillis) throws MicroKernelException {
+ return gate.waitForCommit(oldHeadRevision, maxWaitMillis);
+ }
+
public String getJournal(String fromRevisionId, String toRevisionId) throws MicroKernelException {
if (rep == null) {
throw new IllegalStateException("this instance has already been disposed");
@@ -304,7 +311,9 @@ public class MicroKernelImpl implements
throw new AssertionError("token type: " + t.getTokenType());
}
}
- return cb.doCommit();
+ String newHead = cb.doCommit();
+ gate.commit(newHead);
+ return newHead;
} catch (Exception e) {
throw new MicroKernelException(e);
}
Modified: jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/api/MicroKernel.java
URL: http://svn.apache.org/viewvc/jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/api/MicroKernel.java?rev=1143104&r1=1143103&r2=1143104&view=diff
==============================================================================
--- jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/api/MicroKernel.java (original)
+++ jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/api/MicroKernel.java Tue Jul 5 15:30:52 2011
@@ -123,6 +123,21 @@ public interface MicroKernel {
throws MicroKernelException;
/**
+ * Wait for a commit to occur that is newer than the given revision number.
+ *
+ * This method is useful efficient polling. The method will return the current head revision
+ * if it is newer than the given old revision number, or wait until the given number of
+ * milliseconds passed or a new head revision is available.
+ *
+ * @param maxWaitMillis the maximum number of milliseconds to wait (0 if the
+ * method should not wait).
+ * @return the current head revision
+ * @throws MicroKernelException if an error occurs
+ */
+
+ String waitForCommit(String oldHeadRevision, long maxWaitMillis) throws MicroKernelException;
+
+ /**
* Returns a revision journal, starting with <code>fromRevisionId</code>
* and ending with <code>toRevisionId</code>.
* <p/>
Modified: jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/mem/MemoryKernelImpl.java
URL: http://svn.apache.org/viewvc/jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/mem/MemoryKernelImpl.java?rev=1143104&r1=1143103&r2=1143104&view=diff
==============================================================================
--- jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/mem/MemoryKernelImpl.java (original)
+++ jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/mem/MemoryKernelImpl.java Tue Jul 5 15:30:52 2011
@@ -26,6 +26,7 @@ import java.util.TreeMap;
import org.apache.jackrabbit.mk.api.MicroKernel;
import org.apache.jackrabbit.mk.json.JsopBuilder;
import org.apache.jackrabbit.mk.json.JsopTokenizer;
+import org.apache.jackrabbit.mk.util.CommitGate;
import org.apache.jackrabbit.mk.util.NonDescendingClock;
import org.apache.jackrabbit.mk.util.PathUtils;
@@ -43,6 +44,7 @@ public class MemoryKernelImpl implements
private ArrayList<Revision> revisionList;
private NodeImpl headRoot;
private NonDescendingClock clock = new NonDescendingClock(System.currentTimeMillis());
+ private final CommitGate gate = new CommitGate();
public synchronized static MemoryKernelImpl get(String name) {
MemoryKernelImpl instance = INSTANCES.get(name);
@@ -85,10 +87,9 @@ public class MemoryKernelImpl implements
headRevId++;
jsonDiff = apply(path, jsonDiff);
commit(jsonDiff, message);
-
- System.out.println("commit " + getRevisionId(headRevId) + " = " + jsonDiff);
-
- return getHeadRevision();
+ String head = getHeadRevision();
+ gate.commit(head);
+ return head;
}
private String apply(String rootPath, String jsonDiff) {
@@ -174,6 +175,10 @@ public class MemoryKernelImpl implements
return buff.endArray().toString();
}
+ public String waitForCommit(String oldHeadRevision, long maxWaitMillis) {
+ return gate.waitForCommit(oldHeadRevision, maxWaitMillis);
+ }
+
public String getJournal(String fromRevisionId, String toRevisionId) {
long fromRevId = parseRevisionId(fromRevisionId);
long toRevId = parseRevisionId(toRevisionId);
@@ -245,7 +250,7 @@ public class MemoryKernelImpl implements
}
public void dispose() {
- // nothing to do
+ gate.commit("end");
}
}
Added: jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/util/CommitGate.java
URL: http://svn.apache.org/viewvc/jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/util/CommitGate.java?rev=1143104&view=auto
==============================================================================
--- jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/util/CommitGate.java (added)
+++ jackrabbit/sandbox/microkernel/src/main/java/org/apache/jackrabbit/mk/util/CommitGate.java Tue Jul 5 15:30:52 2011
@@ -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.jackrabbit.mk.util;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A gate where listeners can wait for a new commit.
+ */
+public class CommitGate {
+
+ private volatile String currentHead;
+ private volatile AtomicReference<CountDownLatch> latchRef = new AtomicReference<CountDownLatch>();
+
+ /**
+ * Wait for a new commit to occur. In very few cases, this method may return
+ * with the old head before the requested timeout.
+ *
+ * @param lastHead the last head
+ * @param millis the maximum number of milliseconds to wait (0 means don't wait)
+ * @return the new head (or old head, if no new commit occurred)
+ */
+ public String waitForCommit(String lastHead, long millis) {
+ if (millis == 0 || (currentHead != null && !currentHead.equals(lastHead))) {
+ return currentHead;
+ }
+ CountDownLatch latch = latchRef.get();
+ if (latch == null) {
+ latch = new CountDownLatch(1);
+ CountDownLatch old = latchRef.getAndSet(latch);
+ if (old != null) {
+ // may cause a spurious release, but that's ok
+ old.countDown();
+ }
+ }
+ try {
+ latch.await(millis, TimeUnit.MILLISECONDS);
+ } catch (InterruptedException e) {
+ // ignore
+ }
+ return currentHead;
+ }
+
+ /**
+ * Commit a new head. Waiting threads are awoken.
+ *
+ * @param newHead the new head
+ */
+ public void commit(String newHead) {
+ currentHead = newHead;
+ CountDownLatch latch = latchRef.get();
+ if (latch != null) {
+ // may cause a spurious release, but that's ok
+ latch.countDown();
+ latch = latchRef.getAndSet(null);
+ if (latch != null) {
+ latch.countDown();
+ }
+ }
+ }
+
+}