/*******************************************************************************
 * Copyright (c) 2014, 2015 Cisco Systems, Inc. and others.  All rights reserved.
 *  
 *  This program and the accompanying materials are made available under the
 *  terms of the Eclipse Public License v1.0 which accompanies this distribution,
 *  and is available at http://www.eclipse.org/legal/epl-v10.html
 *  
 *******************************************************************************/
package com.cisco.yangide.core.buffer;

import java.util.ArrayList;

import com.cisco.yangide.core.model.YangElement;

/**
 * @author Konstantin Zaitsev
 * @date Jun 24, 2014
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class BufferCache extends OverflowingLRUCache {

    private ThreadLocal buffersToClose = new ThreadLocal();

    /**
     * Constructs a new buffer cache of the given size.
     */
    public BufferCache(int size) {
        super(size);
    }

    /**
     * Constructs a new buffer cache of the given size.
     */
    public BufferCache(int size, int overflow) {
        super(size, overflow);
    }

    /**
     * Returns true if the buffer is successfully closed and removed from the cache, otherwise
     * false.
     * <p>
     * NOTE: this triggers an external removal of this buffer by closing the buffer.
     */
    protected boolean close(LRUCacheEntry entry) {
        IBuffer buffer = (IBuffer) entry.value;

        // prevent buffer that have unsaved changes or working copy buffer to be removed
        // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=39311
        if (!((YangElement) buffer.getOwner()).canBufferBeRemovedFromCache(buffer)) {
            return false;
        } else {
            ArrayList buffers = (ArrayList) this.buffersToClose.get();
            if (buffers == null) {
                buffers = new ArrayList();
                this.buffersToClose.set(buffers);
            }
            buffers.add(buffer);
            return true;
        }
    }

    void closeBuffers() {
        ArrayList buffers = (ArrayList) this.buffersToClose.get();
        if (buffers == null)
            return;
        this.buffersToClose.set(null);
        for (int i = 0, length = buffers.size(); i < length; i++) {
            ((IBuffer) buffers.get(i)).close();
        }
    }

    /**
     * Returns a new instance of the reciever.
     */
    protected LRUCache newInstance(int size, int newOverflow) {
        return new BufferCache(size, newOverflow);
    }
}