/*
* 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.contribution.scanner;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.tuscany.sca.contribution.Artifact;
import org.apache.tuscany.sca.contribution.Contribution;
import org.apache.tuscany.sca.contribution.ContributionFactory;
import org.apache.tuscany.sca.contribution.processor.ContributionReadException;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.core.FactoryExtensionPoint;
import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
/**
* Default implementation of a contribution scanner extension point.
*
* @version $Rev: 891986 $ $Date: 2009-12-17 23:28:45 +0000 (Thu, 17 Dec 2009) $
*/
public class DefaultContributionScannerExtensionPoint implements ContributionScannerExtensionPoint {
private Map<String, ContributionScanner> scanners = new HashMap<String, ContributionScanner>();
private boolean loaded;
private ExtensionPointRegistry registry;
public DefaultContributionScannerExtensionPoint(ExtensionPointRegistry registry) {
this.registry = registry;
}
public void addContributionScanner(ContributionScanner scanner) {
scanners.put(scanner.getContributionType(), scanner);
}
public void removeContributionScanner(ContributionScanner scanner) {
scanners.remove(scanner.getContributionType());
}
public ContributionScanner getContributionScanner(String contentType) {
loadScanners();
return scanners.get(contentType);
}
private synchronized void loadScanners() {
if (loaded)
return;
// Get the scanner service declarations
Collection<ServiceDeclaration> scannerDeclarations;
try {
scannerDeclarations = registry.getServiceDiscovery().getServiceDeclarations(ContributionScanner.class.getName());
} catch (IOException e) {
throw new IllegalStateException(e);
}
for (ServiceDeclaration scannerDeclaration: scannerDeclarations) {
Map<String, String> attributes = scannerDeclaration.getAttributes();
// Load a URL artifact scanner
String contributionType = attributes.get("type");
// Create a scanner wrapper and register it
ContributionScanner scanner = new LazyContributionScanner(registry, contributionType, scannerDeclaration);
addContributionScanner(scanner);
}
loaded = true;
}
/**
* A facade for contribution scanners.
*/
private static class LazyContributionScanner implements ContributionScanner {
private ExtensionPointRegistry registry;
private ServiceDeclaration scannerDeclaration;
private String contributionType;
private ContributionScanner scanner;
private ContributionFactory contributionFactory;
private LazyContributionScanner(ExtensionPointRegistry registry, String contributionType, ServiceDeclaration scannerDeclaration) {
this.registry = registry;
this.scannerDeclaration = scannerDeclaration;
this.contributionType = contributionType;
FactoryExtensionPoint factories = registry.getExtensionPoint(FactoryExtensionPoint.class);
this.contributionFactory = factories.getFactory(ContributionFactory.class);
}
public List<Artifact> scan(Contribution contributionSourceURL) throws ContributionReadException {
return getScanner().scan(contributionSourceURL);
}
public String getContributionType() {
return contributionType;
}
private ContributionScanner getScanner() {
if (scanner == null) {
try {
Class<ContributionScanner> scannerClass = (Class<ContributionScanner>)scannerDeclaration.loadClass();
Constructor<ContributionScanner> constructor = scannerClass.getConstructor(ContributionFactory.class);
scanner = constructor.newInstance(contributionFactory);
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
return scanner;
}
}
}