Fix ModuleCapability/ModuleRequirement hashcode/equals according to API

The API of Capability/Requirement currently defines the contract to be:
This Capability/Requirement is equal to another Capability/Requirement
if they have the same namespace, directives and attributes and are
declared by the same resource.

But Equinox currently implements hashCode/equals in terms of object
identity.

bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/container/ModuleCapability.java

@@ -16,8 +16,10 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 import org.osgi.framework.namespace.NativeNamespace;
 import org.osgi.framework.wiring.BundleCapability;
+import org.osgi.resource.Capability;
 
 /**
  * An implementation of {@link BundleCapability}.
@@ -30,6 +32,7 @@ public final class ModuleCapability implements BundleCapability {
 	private final Map<String, Object> attributes;
 	private final Map<String, Object> transientAttrs;
 	private final ModuleRevision revision;
+	private transient int hashCode;
 
 	ModuleCapability(String namespace, Map<String, String> directives, Map<String, Object> attributes,
 			ModuleRevision revision) {
@@ -93,4 +96,26 @@ public ModuleRevision getResource() {
 	public String toString() {
 		return namespace + ModuleContainer.toString(attributes, false) + ModuleContainer.toString(directives, true);
 	}
+
+	@Override
+	public int hashCode() {
+		if (hashCode != 0) {
+			return hashCode;
+		}
+		return hashCode = Objects.hash(namespace, directives, attributes, revision);
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj instanceof Capability) {
+			Capability other = (Capability) obj;
+			return Objects.equals(revision, other.getResource()) && Objects.equals(namespace, other.getNamespace())
+					&& Objects.equals(directives, other.getDirectives())
+					&& Objects.equals(attributes, other.getAttributes());
+		}
+		return false;
+	}
 }

bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/container/ModuleDatabase.java

@@ -25,6 +25,7 @@
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -1084,7 +1085,7 @@ public static void store(ModuleDatabase moduleDatabase, DataOutputStream out, bo
 			}
 
 			// Now persist all the Strings
-			Map<Object, Integer> objectTable = new HashMap<>();
+			Map<Object, Integer> objectTable = new IdentityHashMap<>();
 			allStrings.remove(null);
 			out.writeInt(allStrings.size());
 			for (String string : allStrings) {

bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/container/ModuleRequirement.java

@@ -15,6 +15,7 @@
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 import org.eclipse.osgi.internal.container.Capabilities;
 import org.eclipse.osgi.internal.framework.FilterImpl;
 import org.osgi.framework.InvalidSyntaxException;
@@ -24,6 +25,7 @@
 import org.osgi.framework.wiring.BundleCapability;
 import org.osgi.framework.wiring.BundleRequirement;
 import org.osgi.resource.Namespace;
+import org.osgi.resource.Requirement;
 
 /**
  * An implementation of {@link BundleRequirement}. This requirement implements
@@ -38,6 +40,7 @@ public class ModuleRequirement implements BundleRequirement {
 	private final Map<String, String> directives;
 	private final Map<String, Object> attributes;
 	private final ModuleRevision revision;
+	private transient int hashCode;
 
 	ModuleRequirement(String namespace, Map<String, String> directives, Map<String, ?> attributes,
 			ModuleRevision revision) {
@@ -153,4 +156,26 @@ ModuleRequirement getOriginal() {
 		}
 	}
 
+	@Override
+	public int hashCode() {
+		if (hashCode != 0) {
+			return hashCode;
+		}
+		return hashCode = Objects.hash(namespace, directives, attributes, revision);
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj instanceof Requirement) {
+			Requirement other = (Requirement) obj;
+			return Objects.equals(revision, other.getResource()) && Objects.equals(namespace, other.getNamespace())
+					&& Objects.equals(directives, other.getDirectives())
+					&& Objects.equals(attributes, other.getAttributes());
+		}
+		return false;
+	}
+
 }