/*
 * Copyright 2005 the original author or authors.
 * 
 * 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.wamblee.photos.concurrent;

import java.io.IOException;
import java.io.InputStream;

import org.wamblee.photos.model.Album;
import org.wamblee.photos.model.Path;
import org.wamblee.photos.model.Photo;
import org.wamblee.photos.model.PhotoEntry;

/**
 * Decorator for an album providing defined behavior when used in a concurrent setting. 
 */
public class ConcurrentAlbum extends ConcurrentPhotoEntry implements Album {
    
    /**
     * Constructs concurrent album as a decorator for an album implementation. 
     * @param aAlbum Album to decorate. 
     */
    public ConcurrentAlbum(Album aAlbum) {
        super(aAlbum); 
    }
    
    private Album decorated() {
        return (Album)getEntry(); 
    }
    
    /**
     * Creates a decorate for the photo entry to make it safe for concurrent access.  
     * @param aEntry Entry to decorate
     * @return Decorated photo. 
     */
    private <T extends PhotoEntry> T decorate(T aEntry) {
        if ( aEntry == null ) {
            return null;    
        }
        else if ( aEntry instanceof Photo) {
            return (T) new ConcurrentPhoto((Photo)aEntry); 
        } else if ( aEntry instanceof Album) {
            return (T) new ConcurrentAlbum((Album)aEntry); 
        } else {
            throw new IllegalArgumentException("Entry is neither a photo nor an album: " + aEntry); 
        }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#getEntry(java.lang.String)
     */
    public PhotoEntry getEntry(String aPath) {
        lock().acquireRead(); 
        try {
            return decorate(decorated().getEntry(aPath));    
        } finally {
            lock().releaseRead(); 
        }
    }
    
    public PhotoEntry getEntry(Path aPath) {
    	 lock().acquireRead(); 
         try {
             return decorate(decorated().getEntry(aPath));    
         } finally {
             lock().releaseRead(); 
         }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#getEntry(int)
     */
    public PhotoEntry getEntry(int aIndex) {
        lock().acquireRead(); 
        try {
            return decorate(decorated().getEntry(aIndex)); 
        } finally {
            lock().releaseRead(); 
        }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#size()
     */
    public int size() {
        lock().acquireRead(); 
        try {
            return decorated().size(); 
        } finally {
            lock().releaseRead(); 
        }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#addImage(java.lang.String, java.io.InputStream)
     */
    public void addImage(String aId, InputStream aImage) throws IOException {
        lock().acquireWrite();
        try {
            decorated().addImage(aId, aImage); 
        } finally {
            lock().releaseWrite(); 
        }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#addAlbum(java.lang.String)
     */
    public void addAlbum(String aId) throws IOException {
        lock().acquireWrite();
        try {
            decorated().addAlbum(aId);  
        } finally {
            lock().releaseWrite(); 
        }
    }

    /* (non-Javadoc)
     * @see org.wamblee.photos.model.Album#removeEntry(java.lang.String)
     */
    public void removeEntry(String aId) throws IOException {
        lock().acquireWrite();
        try {
            decorated().removeEntry(aId);  
        } finally {
            lock().releaseWrite(); 
        }
    }
    
    public Photo findPhotoBefore(String aId) {
    	 lock().acquireWrite();
         try {
             return decorate(decorated().findPhotoBefore(aId));  
         } finally {
             lock().releaseWrite(); 
         }
    }
    
    public Photo findPhotoAfter(String aId) {
    	 lock().acquireWrite();
         try {
             return decorate(decorated().findPhotoAfter(aId));  
         } finally {
             lock().releaseWrite(); 
         }
    }
}