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/**
 * Copyright 2007-2012 Bull S.A.S.
 *
 * Licensed 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.ow2.util.archive.impl;

import java.util.HashMap;
import java.util.Map;

import org.ow2.util.archive.api.IArchive;
import org.ow2.util.archive.api.IArchiveFactory;
import org.ow2.util.archive.api.IArchiveManager;
import org.ow2.util.log.Log;
import org.ow2.util.log.LogFactory;

/**
 * Creates an archive for the given type.
 * @author Florent Benoit
 */
public final class ArchiveManager implements IArchiveManager {

    /**
     * Logger.
     */
    private static Log logger = LogFactory.getLog(ArchiveManager.class);

    /**
     * Unique instance of this class.
     */
    private static ArchiveManager archiveManager;

    /**
     * Mapping between class and the associated factories.

     * ie : File <--> DefaultArchiveFactory.
     */
    private Map, IArchiveFactory> factories = new HashMap, IArchiveFactory>();

    /**
     * Private constructor as only one instance is built.
     */
    private ArchiveManager() {
        addFactory(new DefaultArchiveFactory());
        addFactory(new URLArchiveFactory());
    }

    /**
     * Gets the unique instance of this class.
     * @return the unique instance.
     */
    public static ArchiveManager getInstance() {
        if (archiveManager == null) {
            archiveManager = new ArchiveManager();
        }
        return archiveManager;
    }

    /**
     * Adds the given factory on this manager. It will look the generic info
     * used by this class to find the class object managed by this factory.
     * @param factory the factory to add.
     */
    public void addFactory(final IArchiveFactory factory) {

        Class factoryClass = factory.getClass();
        Class argumentClass = factory.getSupportedClass();

        logger.debug("Adding factory '" + factoryClass.getName() + "' for class '" + argumentClass + "'.");

        // Add factory
        factories.put(argumentClass, factory);

    }

    /**
     * Removes the given factory on this manager. It will look the generic info
     * used by this class to find the class object managed by this factory.
     * @param factory the factory to remove.
     */
    public void removeFactory(final IArchiveFactory factory) {

        Class factoryClass = factory.getClass();
        Class argumentClass = factory.getSupportedClass();

        if (factories.containsKey(argumentClass)) {
            logger.debug("Removing factory '" + factoryClass.getName() + "' for class '" + argumentClass + "'.");

            // Remove factory
            factories.remove(argumentClass);
        } else {
            logger.debug("Factory '" + factoryClass.getName() + "' was not registered in the ArchiveManager.");
        }
    }

    /**
     * Creates an EZBArchive implementation object for the given object.
     * @param o object to wrap into an EZBArchive.
     * @return the created archive.
     */
    @SuppressWarnings("unchecked")
    public IArchive getArchive(final Object o) {
        // try to see if there is a matching factory
        Class objectClass = o.getClass();

        // Factory ?
        IArchiveFactory factory = factories.get(objectClass);

        if (factory == null) {

            // Iterates over the registered classes and find the assignable class
            for (Class cls : factories.keySet()) {
                if (cls.isAssignableFrom(objectClass) && factory == null) {
                    // we found a match
                    factory = factories.get(cls);
                }
            }

            // if after all, factory is still null, raise an Exception
            if (factory == null) {
                throw new IllegalArgumentException("No factory found for the type '" + objectClass + "'.");
            }
        }

        return factory.create(o);
    }

}