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/*
* 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.tuscany.sca.workspace.builder;
import java.lang.reflect.Constructor;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import org.apache.tuscany.sca.contribution.Contribution;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.core.FactoryExtensionPoint;
import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
import org.apache.tuscany.sca.monitor.Monitor;
import org.apache.tuscany.sca.workspace.Workspace;
/**
* Default implementation of a provider factory extension point.
*
* @version $Rev$ $Date$
*/
public class DefaultContributionBuilderExtensionPoint implements ContributionBuilderExtensionPoint {
private ExtensionPointRegistry registry;
private final Map<String, ContributionBuilder> builders = new HashMap<String, ContributionBuilder>();
private boolean loaded;
public DefaultContributionBuilderExtensionPoint(ExtensionPointRegistry registry) {
this.registry = registry;
}
public void addContributionBuilder(ContributionBuilder builder) {
builders.put(builder.getID(), builder);
}
public void removeContributionBuilder(ContributionBuilder builder) {
builders.remove(builder.getID());
}
public ContributionBuilder getContributionBuilder(String id) {
loadBuilders();
return builders.get(id);
}
/**
* Load builders declared under META-INF/services.
*/
private void loadBuilders() {
if (loaded)
return;
FactoryExtensionPoint factories = registry.getExtensionPoint(FactoryExtensionPoint.class);
// Get the provider factory service declarations
Set<ServiceDeclaration> builderDeclarations;
ServiceDiscovery serviceDiscovery = ServiceDiscovery.getInstance();
try {
builderDeclarations = serviceDiscovery.getServiceDeclarations(ContributionBuilder.class.getName());
} catch (Exception e) {
throw new IllegalStateException(e);
}
for (ServiceDeclaration builderDeclaration : builderDeclarations) {
Map<String, String> attributes = builderDeclaration.getAttributes();
String id = attributes.get("id");
ContributionBuilder builder = new LazyContributionBuilder(id, builderDeclaration, this, factories);
builders.put(id, builder);
}
}
/**
* A wrapper around a contribution builder allowing lazy
* loading and initialization of implementation providers.
*/
private static class LazyContributionBuilder implements ContributionBuilder {
private FactoryExtensionPoint factories;
private String id;
private ServiceDeclaration builderDeclaration;
private ContributionBuilder builder;
private ContributionBuilderExtensionPoint builders;
private LazyContributionBuilder(String id, ServiceDeclaration factoryDeclaration,
ContributionBuilderExtensionPoint builders, FactoryExtensionPoint factories) {
this.id = id;
this.builderDeclaration = factoryDeclaration;
this.builders = builders;
this.factories = factories;
}
public String getID() {
return id;
}
public void build(Contribution contribution, Workspace workspace, Monitor monitor) throws ContributionBuilderException {
getBuilder().build(contribution, workspace, monitor);
}
private ContributionBuilder getBuilder() {
if (builder == null) {
try {
Class<ContributionBuilder> builderClass = (Class<ContributionBuilder>)builderDeclaration.loadClass();
try {
Constructor<ContributionBuilder> constructor = builderClass.getConstructor(FactoryExtensionPoint.class);
builder = constructor.newInstance(factories);
} catch (NoSuchMethodException e) {
Constructor<ContributionBuilder> constructor = builderClass.getConstructor(ContributionBuilderExtensionPoint.class, FactoryExtensionPoint.class);
builder = constructor.newInstance(builders, factories);
}
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
return builder;
}
}
}
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