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Posted to commits@karaf.apache.org by gn...@apache.org on 2014/04/07 10:53:01 UTC

[10/13] [KARAF-2888] New FeaturesService based on the real OSGi resolver

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/CapabilitySet.java
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diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/CapabilitySet.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/CapabilitySet.java
new file mode 100644
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--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/CapabilitySet.java
@@ -0,0 +1,612 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.lang.reflect.Array;
+import java.lang.reflect.Constructor;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.TreeMap;
+
+import org.osgi.framework.Constants;
+import org.osgi.resource.Capability;
+
+public class CapabilitySet
+{
+    private final Map<String, Map<Object, Set<Capability>>> m_indices;
+    private final Set<Capability> m_capSet = new HashSet<Capability>();
+
+public void dump()
+{
+    for (Entry<String, Map<Object, Set<Capability>>> entry : m_indices.entrySet())
+    {
+        boolean header1 = false;
+        for (Entry<Object, Set<Capability>> entry2 : entry.getValue().entrySet())
+        {
+            boolean header2 = false;
+            for (Capability cap : entry2.getValue())
+            {
+                if (!header1)
+                {
+                    System.out.println(entry.getKey() + ":");
+                    header1 = true;
+                }
+                if (!header2)
+                {
+                    System.out.println("   " + entry2.getKey());
+                    header2 = true;
+                }
+                System.out.println("      " + cap);
+            }
+        }
+    }
+}
+
+    public CapabilitySet(List<String> indexProps)
+    {
+        m_indices = new TreeMap<String, Map<Object, Set<Capability>>>();
+        for (int i = 0; (indexProps != null) && (i < indexProps.size()); i++)
+        {
+            m_indices.put(
+                indexProps.get(i), new HashMap<Object, Set<Capability>>());
+        }
+    }
+
+    public void addCapability(Capability cap)
+    {
+        m_capSet.add(cap);
+
+        // Index capability.
+        for (Entry<String, Map<Object, Set<Capability>>> entry : m_indices.entrySet())
+        {
+            Object value = cap.getAttributes().get(entry.getKey());
+            if (value != null)
+            {
+                if (value.getClass().isArray())
+                {
+                    value = convertArrayToList(value);
+                }
+
+                Map<Object, Set<Capability>> index = entry.getValue();
+
+                if (value instanceof Collection)
+                {
+                    Collection c = (Collection) value;
+                    for (Object o : c)
+                    {
+                        indexCapability(index, cap, o);
+                    }
+                }
+                else
+                {
+                    indexCapability(index, cap, value);
+                }
+            }
+        }
+    }
+
+    private void indexCapability(
+        Map<Object, Set<Capability>> index, Capability cap, Object capValue)
+    {
+        Set<Capability> caps = index.get(capValue);
+        if (caps == null)
+        {
+            caps = new HashSet<Capability>();
+            index.put(capValue, caps);
+        }
+        caps.add(cap);
+    }
+
+    public void removeCapability(Capability cap)
+    {
+        if (m_capSet.remove(cap))
+        {
+            for (Entry<String, Map<Object, Set<Capability>>> entry : m_indices.entrySet())
+            {
+                Object value = cap.getAttributes().get(entry.getKey());
+                if (value != null)
+                {
+                    if (value.getClass().isArray())
+                    {
+                        value = convertArrayToList(value);
+                    }
+
+                    Map<Object, Set<Capability>> index = entry.getValue();
+
+                    if (value instanceof Collection)
+                    {
+                        Collection c = (Collection) value;
+                        for (Object o : c)
+                        {
+                            deindexCapability(index, cap, o);
+                        }
+                    }
+                    else
+                    {
+                        deindexCapability(index, cap, value);
+                    }
+                }
+            }
+        }
+    }
+
+    private void deindexCapability(
+        Map<Object, Set<Capability>> index, Capability cap, Object value)
+    {
+        Set<Capability> caps = index.get(value);
+        if (caps != null)
+        {
+            caps.remove(cap);
+            if (caps.isEmpty())
+            {
+                index.remove(value);
+            }
+        }
+    }
+
+    public Set<Capability> match(SimpleFilter sf, boolean obeyMandatory)
+    {
+        Set<Capability> matches = match(m_capSet, sf);
+        return (obeyMandatory)
+            ? matchMandatory(matches, sf)
+            : matches;
+    }
+
+    private Set<Capability> match(Set<Capability> caps, SimpleFilter sf)
+    {
+        Set<Capability> matches = new HashSet<Capability>();
+
+        if (sf.getOperation() == SimpleFilter.MATCH_ALL)
+        {
+            matches.addAll(caps);
+        }
+        else if (sf.getOperation() == SimpleFilter.AND)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For AND we calculate the intersection of each subfilter.
+            // We can short-circuit the AND operation if there are no
+            // remaining capabilities.
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; (caps.size() > 0) && (i < sfs.size()); i++)
+            {
+                matches = match(caps, sfs.get(i));
+                caps = matches;
+            }
+        }
+        else if (sf.getOperation() == SimpleFilter.OR)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For OR we calculate the union of each subfilter.
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; i < sfs.size(); i++)
+            {
+                matches.addAll(match(caps, sfs.get(i)));
+            }
+        }
+        else if (sf.getOperation() == SimpleFilter.NOT)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For OR we calculate the union of each subfilter.
+            matches.addAll(caps);
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; i < sfs.size(); i++)
+            {
+                matches.removeAll(match(caps, sfs.get(i)));
+            }
+        }
+        else
+        {
+            Map<Object, Set<Capability>> index = m_indices.get(sf.getName());
+            if ((sf.getOperation() == SimpleFilter.EQ) && (index != null))
+            {
+                Set<Capability> existingCaps = index.get(sf.getValue());
+                if (existingCaps != null)
+                {
+                    matches.addAll(existingCaps);
+                    matches.retainAll(caps);
+                }
+            }
+            else
+            {
+                for (Iterator<Capability> it = caps.iterator(); it.hasNext(); )
+                {
+                    Capability cap = it.next();
+                    Object lhs = cap.getAttributes().get(sf.getName());
+                    if (lhs != null)
+                    {
+                        if (compare(lhs, sf.getValue(), sf.getOperation()))
+                        {
+                            matches.add(cap);
+                        }
+                    }
+                }
+            }
+        }
+
+        return matches;
+    }
+
+    public static boolean matches(Capability cap, SimpleFilter sf)
+    {
+        return matchesInternal(cap, sf) && matchMandatory(cap, sf);
+    }
+
+    private static boolean matchesInternal(Capability cap, SimpleFilter sf)
+    {
+        boolean matched = true;
+
+        if (sf.getOperation() == SimpleFilter.MATCH_ALL)
+        {
+            matched = true;
+        }
+        else if (sf.getOperation() == SimpleFilter.AND)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For AND we calculate the intersection of each subfilter.
+            // We can short-circuit the AND operation if there are no
+            // remaining capabilities.
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; matched && (i < sfs.size()); i++)
+            {
+                matched = matchesInternal(cap, sfs.get(i));
+            }
+        }
+        else if (sf.getOperation() == SimpleFilter.OR)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For OR we calculate the union of each subfilter.
+            matched = false;
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; !matched && (i < sfs.size()); i++)
+            {
+                matched = matchesInternal(cap, sfs.get(i));
+            }
+        }
+        else if (sf.getOperation() == SimpleFilter.NOT)
+        {
+            // Evaluate each subfilter against the remaining capabilities.
+            // For OR we calculate the union of each subfilter.
+            List<SimpleFilter> sfs = (List<SimpleFilter>) sf.getValue();
+            for (int i = 0; i < sfs.size(); i++)
+            {
+                matched = !(matchesInternal(cap, sfs.get(i)));
+            }
+        }
+        else
+        {
+            matched = false;
+            Object lhs = cap.getAttributes().get(sf.getName());
+            if (lhs != null)
+            {
+                matched = compare(lhs, sf.getValue(), sf.getOperation());
+            }
+        }
+
+        return matched;
+    }
+
+    private static Set<Capability> matchMandatory(
+        Set<Capability> caps, SimpleFilter sf)
+    {
+        for (Iterator<Capability> it = caps.iterator(); it.hasNext(); )
+        {
+            Capability cap = it.next();
+            if (!matchMandatory(cap, sf))
+            {
+                it.remove();
+            }
+        }
+        return caps;
+    }
+
+    private static boolean matchMandatory(Capability cap, SimpleFilter sf)
+    {
+        if (cap instanceof CapabilityImpl) {
+            for (Entry<String, Object> entry : cap.getAttributes().entrySet())
+            {
+                if (((CapabilityImpl) cap).isAttributeMandatory(entry.getKey())
+                    && !matchMandatoryAttribute(entry.getKey(), sf))
+                {
+                    return false;
+                }
+            }
+        } else {
+            String value = cap.getDirectives().get(Constants.MANDATORY_DIRECTIVE);
+            if (value != null) {
+                List<String> names = ResourceBuilder.parseDelimitedString(value, ",");
+                for (Entry<String, Object> entry : cap.getAttributes().entrySet())
+                {
+                    if (names.contains(entry.getKey())
+                            && !matchMandatoryAttribute(entry.getKey(), sf))
+                    {
+                        return false;
+                    }
+                }
+            }
+
+        }
+        return true;
+    }
+
+    private static boolean matchMandatoryAttribute(String attrName, SimpleFilter sf)
+    {
+        if ((sf.getName() != null) && sf.getName().equals(attrName))
+        {
+            return true;
+        }
+        else if (sf.getOperation() == SimpleFilter.AND)
+        {
+            List list = (List) sf.getValue();
+            for (int i = 0; i < list.size(); i++)
+            {
+                SimpleFilter sf2 = (SimpleFilter) list.get(i);
+                if ((sf2.getName() != null)
+                    && sf2.getName().equals(attrName))
+                {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    private static final Class<?>[] STRING_CLASS = new Class[] { String.class };
+
+    private static boolean compare(Object lhs, Object rhsUnknown, int op)
+    {
+        if (lhs == null)
+        {
+            return false;
+        }
+
+        // If this is a PRESENT operation, then just return true immediately
+        // since we wouldn't be here if the attribute wasn't present.
+        if (op == SimpleFilter.PRESENT)
+        {
+            return true;
+        }
+
+        // If the type is comparable, then we can just return the
+        // result immediately.
+        if (lhs instanceof Comparable)
+        {
+            // Spec says SUBSTRING is false for all types other than string.
+            if ((op == SimpleFilter.SUBSTRING) && !(lhs instanceof String))
+            {
+                return false;
+            }
+
+            Object rhs;
+            if (op == SimpleFilter.SUBSTRING)
+            {
+                rhs = rhsUnknown;
+            }
+            else
+            {
+                try
+                {
+                    rhs = coerceType(lhs, (String) rhsUnknown);
+                }
+                catch (Exception ex)
+                {
+                    return false;
+                }
+            }
+
+            switch (op)
+            {
+                case SimpleFilter.EQ :
+                    try
+                    {
+                        return (((Comparable) lhs).compareTo(rhs) == 0);
+                    }
+                    catch (Exception ex)
+                    {
+                        return false;
+                    }
+                case SimpleFilter.GTE :
+                    try
+                    {
+                        return (((Comparable) lhs).compareTo(rhs) >= 0);
+                    }
+                    catch (Exception ex)
+                    {
+                        return false;
+                    }
+                case SimpleFilter.LTE :
+                    try
+                    {
+                        return (((Comparable) lhs).compareTo(rhs) <= 0);
+                    }
+                    catch (Exception ex)
+                    {
+                        return false;
+                    }
+                case SimpleFilter.APPROX :
+                    return compareApproximate(((Comparable) lhs), rhs);
+                case SimpleFilter.SUBSTRING :
+                    return SimpleFilter.compareSubstring((List<String>) rhs, (String) lhs);
+                default:
+                    throw new RuntimeException(
+                        "Unknown comparison operator: " + op);
+            }
+        }
+        // Booleans do not implement comparable, so special case them.
+        else if (lhs instanceof Boolean)
+        {
+            Object rhs;
+            try
+            {
+                rhs = coerceType(lhs, (String) rhsUnknown);
+            }
+            catch (Exception ex)
+            {
+                return false;
+            }
+
+            switch (op)
+            {
+                case SimpleFilter.EQ :
+                case SimpleFilter.GTE :
+                case SimpleFilter.LTE :
+                case SimpleFilter.APPROX :
+                    return (lhs.equals(rhs));
+                default:
+                    throw new RuntimeException(
+                        "Unknown comparison operator: " + op);
+            }
+        }
+
+        // If the LHS is not a comparable or boolean, check if it is an
+        // array. If so, convert it to a list so we can treat it as a
+        // collection.
+        if (lhs.getClass().isArray())
+        {
+            lhs = convertArrayToList(lhs);
+        }
+
+        // If LHS is a collection, then call compare() on each element
+        // of the collection until a match is found.
+        if (lhs instanceof Collection)
+        {
+            for (Iterator iter = ((Collection) lhs).iterator(); iter.hasNext(); )
+            {
+                if (compare(iter.next(), rhsUnknown, op))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        // Spec says SUBSTRING is false for all types other than string.
+        if ((op == SimpleFilter.SUBSTRING) && !(lhs instanceof String))
+        {
+            return false;
+        }
+
+        // Since we cannot identify the LHS type, then we can only perform
+        // equality comparison.
+        try
+        {
+            return lhs.equals(coerceType(lhs, (String) rhsUnknown));
+        }
+        catch (Exception ex)
+        {
+            return false;
+        }
+    }
+
+    private static boolean compareApproximate(Object lhs, Object rhs)
+    {
+        if (rhs instanceof String)
+        {
+            return removeWhitespace((String) lhs)
+                .equalsIgnoreCase(removeWhitespace((String) rhs));
+        }
+        else if (rhs instanceof Character)
+        {
+            return Character.toLowerCase(((Character) lhs))
+                == Character.toLowerCase(((Character) rhs));
+        }
+        return lhs.equals(rhs);
+    }
+
+    private static String removeWhitespace(String s)
+    {
+        StringBuffer sb = new StringBuffer(s.length());
+        for (int i = 0; i < s.length(); i++)
+        {
+            if (!Character.isWhitespace(s.charAt(i)))
+            {
+                sb.append(s.charAt(i));
+            }
+        }
+        return sb.toString();
+    }
+
+    private static Object coerceType(Object lhs, String rhsString) throws Exception
+    {
+        // If the LHS expects a string, then we can just return
+        // the RHS since it is a string.
+        if (lhs.getClass() == rhsString.getClass())
+        {
+            return rhsString;
+        }
+
+        // Try to convert the RHS type to the LHS type by using
+        // the string constructor of the LHS class, if it has one.
+        Object rhs = null;
+        try
+        {
+            // The Character class is a special case, since its constructor
+            // does not take a string, so handle it separately.
+            if (lhs instanceof Character)
+            {
+                rhs = new Character(rhsString.charAt(0));
+            }
+            else
+            {
+                // Spec says we should trim number types.
+                if ((lhs instanceof Number) || (lhs instanceof Boolean))
+                {
+                    rhsString = rhsString.trim();
+                }
+                Constructor ctor = lhs.getClass().getConstructor(STRING_CLASS);
+                ctor.setAccessible(true);
+                rhs = ctor.newInstance(new Object[] { rhsString });
+            }
+        }
+        catch (Exception ex)
+        {
+            throw new Exception(
+                "Could not instantiate class "
+                    + lhs.getClass().getName()
+                    + " from string constructor with argument '"
+                    + rhsString + "' because " + ex);
+        }
+
+        return rhs;
+    }
+
+    /**
+     * This is an ugly utility method to convert an array of primitives
+     * to an array of primitive wrapper objects. This method simplifies
+     * processing LDAP filters since the special case of primitive arrays
+     * can be ignored.
+     * @param array An array of primitive types.
+     * @return An corresponding array using pritive wrapper objects.
+    **/
+    private static List convertArrayToList(Object array)
+    {
+        int len = Array.getLength(array);
+        List list = new ArrayList(len);
+        for (int i = 0; i < len; i++)
+        {
+            list.add(Array.get(array, i));
+        }
+        return list;
+    }
+}

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureNamespace.java
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diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureNamespace.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureNamespace.java
new file mode 100644
index 0000000..e211618
--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureNamespace.java
@@ -0,0 +1,72 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.util.List;
+
+import org.osgi.framework.Version;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Namespace;
+import org.osgi.resource.Resource;
+
+/**
+ */
+public final class FeatureNamespace extends Namespace {
+
+    public static final String FEATURE_NAMESPACE = "karaf.feature";
+
+    public static final String	CAPABILITY_VERSION_ATTRIBUTE	= "version";
+
+    /**
+     * The attribute value identifying the resource
+     * {@link org.osgi.framework.namespace.IdentityNamespace#CAPABILITY_TYPE_ATTRIBUTE type} as an OSGi bundle.
+     *
+     * @see org.osgi.framework.namespace.IdentityNamespace#CAPABILITY_TYPE_ATTRIBUTE
+     */
+    public static final String	TYPE_FEATURE = "karaf.feature";
+
+    public static String getName(Resource resource)
+    {
+        List<Capability> caps = resource.getCapabilities(null);
+        for (Capability cap : caps)
+        {
+            if (cap.getNamespace().equals(FEATURE_NAMESPACE))
+            {
+                return cap.getAttributes().get(FEATURE_NAMESPACE).toString();
+            }
+        }
+        return null;
+    }
+
+    public static Version getVersion(Resource resource)
+    {
+        List<Capability> caps = resource.getCapabilities(null);
+        for (Capability cap : caps)
+        {
+            if (cap.getNamespace().equals(FEATURE_NAMESPACE))
+            {
+                return (Version)
+                        cap.getAttributes().get(CAPABILITY_VERSION_ATTRIBUTE);
+            }
+        }
+        return null;
+    }
+
+
+    private FeatureNamespace() {
+    }
+}

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureResource.java
----------------------------------------------------------------------
diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureResource.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureResource.java
new file mode 100644
index 0000000..7d1671c
--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/FeatureResource.java
@@ -0,0 +1,101 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.felix.utils.version.VersionRange;
+import org.apache.felix.utils.version.VersionTable;
+import org.apache.karaf.features.BundleInfo;
+import org.apache.karaf.features.Dependency;
+import org.apache.karaf.features.Feature;
+import org.apache.karaf.features.internal.util.Macro;
+import org.osgi.framework.BundleException;
+import org.osgi.framework.Constants;
+import org.osgi.framework.Version;
+import org.osgi.framework.namespace.IdentityNamespace;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Requirement;
+import org.osgi.resource.Resource;
+
+/**
+*/
+public class FeatureResource extends ResourceImpl {
+
+    private final Feature feature;
+
+    public static Resource build(Feature feature, String featureRange, Map<String, Resource> locToRes) throws BundleException {
+        FeatureResource resource = new FeatureResource(feature);
+        Map<String, String> dirs = new HashMap<String, String>();
+        Map<String, Object> attrs = new HashMap<String, Object>();
+        attrs.put(FeatureNamespace.FEATURE_NAMESPACE, feature.getName());
+        attrs.put(FeatureNamespace.CAPABILITY_VERSION_ATTRIBUTE, VersionTable.getVersion(feature.getVersion()));
+        resource.addCapability(new CapabilityImpl(resource, FeatureNamespace.FEATURE_NAMESPACE, dirs, attrs));
+        for (BundleInfo info : feature.getBundles()) {
+            if (!info.isDependency()) {
+                Resource res = locToRes.get(info.getLocation());
+                if (res == null) {
+                    throw new IllegalStateException("Resource not found for url " + info.getLocation());
+                }
+                List<Capability> caps = res.getCapabilities(IdentityNamespace.IDENTITY_NAMESPACE);
+                if (caps.size() != 1) {
+                    throw new IllegalStateException("Resource does not have a single " + IdentityNamespace.IDENTITY_NAMESPACE + " capability");
+                }
+                dirs = new HashMap<String, String>();
+                attrs = new HashMap<String, Object>();
+                attrs.put(IdentityNamespace.IDENTITY_NAMESPACE, caps.get(0).getAttributes().get(IdentityNamespace.IDENTITY_NAMESPACE));
+                attrs.put(IdentityNamespace.CAPABILITY_TYPE_ATTRIBUTE, caps.get(0).getAttributes().get(IdentityNamespace.CAPABILITY_TYPE_ATTRIBUTE));
+                attrs.put(IdentityNamespace.CAPABILITY_VERSION_ATTRIBUTE, new VersionRange((Version) caps.get(0).getAttributes().get(IdentityNamespace.CAPABILITY_VERSION_ATTRIBUTE), true));
+                resource.addRequirement(new RequirementImpl(resource, IdentityNamespace.IDENTITY_NAMESPACE, dirs, attrs));
+            }
+        }
+        for (Dependency dep : feature.getDependencies()) {
+            String name = dep.getName();
+            String version = dep.getVersion();
+            if (version.equals("0.0.0")) {
+                version = null;
+            } else if (!version.startsWith("[") && !version.startsWith("(")) {
+                version = Macro.transform(featureRange, version);
+            }
+            dirs = new HashMap<String, String>();
+            attrs = new HashMap<String, Object>();
+            attrs.put(FeatureNamespace.FEATURE_NAMESPACE, name);
+            if (version != null) {
+                attrs.put(FeatureNamespace.CAPABILITY_VERSION_ATTRIBUTE, new VersionRange(version));
+            }
+            resource.addRequirement(new RequirementImpl(resource, FeatureNamespace.FEATURE_NAMESPACE, dirs, attrs));
+        }
+        for (org.apache.karaf.features.Capability cap : feature.getCapabilities()) {
+            resource.addCapabilities(ResourceBuilder.parseCapability(resource, cap.getValue()));
+        }
+        for (org.apache.karaf.features.Requirement req : feature.getRequirements()) {
+            resource.addRequirements(ResourceBuilder.parseRequirement(resource, req.getValue()));
+        }
+        return resource;
+    }
+
+    public FeatureResource(Feature feature) {
+        super(feature.getName(), FeatureNamespace.TYPE_FEATURE, VersionTable.getVersion(feature.getVersion()));
+        this.feature = feature;
+    }
+
+    public Feature getFeature() {
+        return feature;
+    }
+}

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/IdentityCapability.java
----------------------------------------------------------------------
diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/IdentityCapability.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/IdentityCapability.java
new file mode 100644
index 0000000..cdc00d1
--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/IdentityCapability.java
@@ -0,0 +1,63 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.osgi.framework.Version;
+import org.osgi.framework.namespace.IdentityNamespace;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Resource;
+
+class IdentityCapability extends BaseClause implements Capability
+{
+    private final Resource m_resource;
+    private final Map<String, String> m_dirs;
+    private final Map<String, Object> m_attrs;
+
+    public IdentityCapability(Resource resource, String name, String type, Version version)
+    {
+        m_resource = resource;
+        m_dirs = new HashMap<String, String>();
+        m_attrs = new HashMap<String, Object>();
+        m_attrs.put(IdentityNamespace.IDENTITY_NAMESPACE, name);
+        m_attrs.put(IdentityNamespace.CAPABILITY_TYPE_ATTRIBUTE, type);
+        m_attrs.put(IdentityNamespace.CAPABILITY_VERSION_ATTRIBUTE, version);
+    }
+
+    public String getNamespace()
+    {
+        return IdentityNamespace.IDENTITY_NAMESPACE;
+    }
+
+    public Map<String, String> getDirectives()
+    {
+        return m_dirs;
+    }
+
+    public Map<String, Object> getAttributes()
+    {
+        return m_attrs;
+    }
+
+    public Resource getResource()
+    {
+        return m_resource;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/RequirementImpl.java
----------------------------------------------------------------------
diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/RequirementImpl.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/RequirementImpl.java
new file mode 100644
index 0000000..a4ef775
--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/RequirementImpl.java
@@ -0,0 +1,80 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.util.Map;
+
+import org.osgi.framework.Constants;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Requirement;
+import org.osgi.resource.Resource;
+
+public class RequirementImpl extends BaseClause implements Requirement {
+    private final Resource m_resource;
+    private final String m_namespace;
+    private final SimpleFilter m_filter;
+    private final boolean m_optional;
+    private final Map<String, String> m_dirs;
+    private final Map<String, Object> m_attrs;
+
+    public RequirementImpl(
+            Resource resource, String namespace,
+            Map<String, String> dirs, Map<String, Object> attrs, SimpleFilter filter) {
+        m_resource = resource;
+        m_namespace = namespace;
+        m_dirs = dirs;
+        m_attrs = attrs;
+        m_filter = filter;
+        // Find resolution import directives.
+        m_optional = Constants.RESOLUTION_OPTIONAL.equals(m_dirs.get(Constants.RESOLUTION_DIRECTIVE));
+    }
+
+    public RequirementImpl(
+            Resource resource, String namespace,
+            Map<String, String> dirs, Map<String, Object> attrs) {
+        this(resource, namespace, dirs, attrs, SimpleFilter.convert(attrs));
+    }
+
+    public String getNamespace() {
+        return m_namespace;
+    }
+
+    public Map<String, String> getDirectives() {
+        return m_dirs;
+    }
+
+    public Map<String, Object> getAttributes() {
+        return m_attrs;
+    }
+
+    public Resource getResource() {
+        return m_resource;
+    }
+
+    public boolean matches(Capability cap) {
+        return CapabilitySet.matches(cap, getFilter());
+    }
+
+    public boolean isOptional() {
+        return m_optional;
+    }
+
+    public SimpleFilter getFilter() {
+        return m_filter;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/karaf/blob/38502e41/features/core/src/main/java/org/apache/karaf/features/internal/resolver/ResolveContextImpl.java
----------------------------------------------------------------------
diff --git a/features/core/src/main/java/org/apache/karaf/features/internal/resolver/ResolveContextImpl.java b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/ResolveContextImpl.java
new file mode 100644
index 0000000..e2ff793
--- /dev/null
+++ b/features/core/src/main/java/org/apache/karaf/features/internal/resolver/ResolveContextImpl.java
@@ -0,0 +1,102 @@
+/*
+ * 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.karaf.features.internal.resolver;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.osgi.framework.Constants;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Requirement;
+import org.osgi.resource.Resource;
+import org.osgi.resource.Wiring;
+import org.osgi.service.repository.Repository;
+import org.osgi.service.resolver.HostedCapability;
+import org.osgi.service.resolver.ResolveContext;
+
+/**
+*/
+public class ResolveContextImpl extends ResolveContext {
+
+    private final Set<Resource> mandatory;
+    private final Set<Resource> optional;
+    private final Repository repository;
+    private final Map<Resource, Wiring> wirings;
+    private final boolean resolveOptional;
+
+    private final CandidateComparator candidateComparator = new CandidateComparator();
+
+    public ResolveContextImpl(Set<Resource> mandatory,
+                              Set<Resource> optional,
+                              Repository repository,
+                              boolean resolveOptional) {
+        this.mandatory = mandatory;
+        this.optional = optional;
+        this.repository = repository;
+        this.wirings = new HashMap<Resource, Wiring>();
+        this.resolveOptional = resolveOptional;
+    }
+
+    @Override
+    public Collection<Resource> getMandatoryResources() {
+        return mandatory;
+    }
+
+    @Override
+    public Collection<Resource> getOptionalResources() {
+        return optional;
+    }
+
+    @Override
+    public List<Capability> findProviders(Requirement requirement) {
+        List<Capability> caps = new ArrayList<Capability>();
+        Map<Requirement, Collection<Capability>> resMap =
+                repository.findProviders(Collections.singleton(requirement));
+        Collection<Capability> res = resMap != null ? resMap.get(requirement) : null;
+        if (res != null) {
+            caps.addAll(res);
+        }
+        Collections.sort(caps, candidateComparator);
+        return caps;
+    }
+    @Override
+    public int insertHostedCapability(List capabilities, HostedCapability hostedCapability) {
+        for (int i=0; i < capabilities.size(); i++) {
+            Capability cap = (Capability) capabilities.get(i);
+            if (candidateComparator.compare(hostedCapability, cap) <= 0) {
+                capabilities.add(i, hostedCapability);
+                return i;
+            }
+        }
+        capabilities.add(hostedCapability);
+        return capabilities.size() - 1;
+    }
+    @Override
+    public boolean isEffective(Requirement requirement) {
+        return resolveOptional ||
+                !Constants.RESOLUTION_OPTIONAL.equals(requirement.getDirectives().get(Constants.RESOLUTION_DIRECTIVE));
+    }
+    @Override
+    public Map<Resource, Wiring> getWirings() {
+        return wirings;
+    }
+}