sigil/org.cauldron.bld.obr/src/org/cauldron/bld/obr/CachingOBRBundleRepository.java

/*
 * 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.cauldron.bld.obr;

import java.io.File;
import java.lang.ref.SoftReference;
import java.net.URL;
import java.util.LinkedList;
import java.util.List;


import org.cauldron.sigil.model.eclipse.ISigilBundle;
import org.cauldron.sigil.repository.IRepositoryVisitor;

public class CachingOBRBundleRepository extends AbstractOBRBundleRepository {

	private SoftReference<List<ISigilBundle>> bundles;
	
	public CachingOBRBundleRepository(String id, URL repositoryURL, File obrCache, File bundleCache, long updatePeriod) {
		super(id, repositoryURL, obrCache, bundleCache, updatePeriod);
	}
	
	@Override
	public void accept(IRepositoryVisitor visitor, int options) {
		for ( ISigilBundle b : loadFromCache(options) ) {
			if ( !visitor.visit(b) ) {
				break;
			}
		}
	}
	
	public synchronized void refresh() {
		super.refresh();
		if ( bundles != null ) {
			bundles.clear();
			notifyChange();
		}
	}

	private synchronized List<ISigilBundle> loadFromCache(int options) {
		List<ISigilBundle> cached = bundles == null ? null : bundles.get();
		if ( cached == null ) {
			try {
				final LinkedList<ISigilBundle> read = new LinkedList<ISigilBundle>();
				readBundles(new OBRListener() {
					public void handleBundle(ISigilBundle bundle) {
						read.add(bundle);
					}
				});
				cached = read;
				bundles = new SoftReference<List<ISigilBundle>>(cached);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} 
		}
		
		return cached;
	}
}