org.paxle.se.search.impl.SearchProviderContextLocal.java Source code

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Here is the source code for org.paxle.se.search.impl.SearchProviderContextLocal.java

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/**
 * This file is part of the Paxle project.
 * Visit http://www.paxle.net for more information.
 * Copyright 2007-2010 the original author or authors.
 *
 * Licensed under the terms of the Common Public License 1.0 ("CPL 1.0").
 * Any use, reproduction or distribution of this program constitutes the recipient's acceptance of this agreement.
 * The full license text is available under http://www.opensource.org/licenses/cpl1.0.txt
 * or in the file LICENSE.txt in the root directory of the Paxle distribution.
 *
 * Unless required by applicable law or agreed to in writing, this software is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 */

package org.paxle.se.search.impl;

import java.io.IOException;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.ReferencePolicy;
import org.osgi.framework.Filter;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;
import org.osgi.service.component.ComponentContext;
import org.paxle.core.doc.IDocumentFactory;
import org.paxle.core.doc.IIndexerDocument;
import org.paxle.se.search.ISearchProviderContext;
import org.paxle.se.search.SearchProviderContext;

@Component(immediate = true)
@Reference(name = "docFactory", referenceInterface = IDocumentFactory.class, cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE, policy = ReferencePolicy.DYNAMIC, bind = "addDocFactory", unbind = "removeDocFactory", target = "(docType=*)")
public class SearchProviderContextLocal extends ThreadLocal<ISearchProviderContext> {
    private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock();
    private final Lock r = rwl.readLock();
    private final Lock w = rwl.writeLock();

    /**
     * The {@link ComponentContext} of this component
     * @see #activate(ComponentContext)
     */
    protected ComponentContext ctx;

    /**
     * for logging
     */
    protected final Log logger = LogFactory.getLog(this.getClass());

    /**
     * All {@link IDocumentFactory document-factories} registered to the system. 
     * @see #createDocumentForInterface(Class, String)
     */
    protected SortedSet<ServiceReference> docFactoryRefs = new TreeSet<ServiceReference>();

    public SearchProviderContextLocal() {
        SearchProviderContext.setThreadLocal(this);
    }

    @Activate
    protected void activate(ComponentContext context) {
        this.ctx = context;
    }

    protected void addDocFactory(ServiceReference docFactory) {
        try {
            w.lock();
            this.docFactoryRefs.add(docFactory);
        } finally {
            w.unlock();
        }
    }

    protected void removeDocFactory(ServiceReference docFactory) {
        try {
            w.lock();
            this.docFactoryRefs.remove(docFactory);
        } finally {
            w.unlock();
        }
    }

    @Override
    protected ISearchProviderContext initialValue() {
        return new Context();
    }

    protected <DOC> DOC createDocumentForInterface(Class<DOC> docInterface, String filter)
            throws InvalidSyntaxException, IOException {
        final Filter classFilter = ctx.getBundleContext()
                .createFilter(String.format("(%s=%s)", IDocumentFactory.DOCUMENT_TYPE, docInterface.getName()));
        final Filter propsFilter = (filter == null) ? null : ctx.getBundleContext().createFilter(filter);

        ServiceReference factoryRef = null;
        try {
            r.lock();

            // loop through all doc-factories and find one that matches 
            for (ServiceReference ref : docFactoryRefs) {
                if (classFilter.match(ref) && (propsFilter == null || propsFilter.match(ref))) {
                    factoryRef = ref;
                    break;
                }
            }
        } finally {
            r.unlock();
        }

        // no factory found
        if (factoryRef == null)
            return null;

        // creating an document
        final IDocumentFactory factory = (IDocumentFactory) ctx.locateService("docFactory", factoryRef);
        if (factory == null)
            return null;
        return factory.createDocument(docInterface);
    }

    private class Context implements ISearchProviderContext {
        public IIndexerDocument createDocument() throws IOException {
            try {
                return this.createDocument(IIndexerDocument.class, null);
            } catch (InvalidSyntaxException e) {
                // this should not occur
                throw new RuntimeException(e.getMessage());
            }
        }

        public <DocInterface> DocInterface createDocument(Class<DocInterface> docInterface, String filter)
                throws InvalidSyntaxException, IOException {
            if (docInterface == null)
                throw new NullPointerException("The interface-class must not be null");
            return createDocumentForInterface(docInterface, filter);
        }
    }
}