Copyright (c) 2012 Contributors.
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://eclipse.org/legal/epl-v10.html
Contributors:
  John Kew (vmware)         	initial implementation
  Lyor Goldstein (vmware)	add support for weaved class being re-defined
/*******************************************************************************
 * Copyright (c) 2012 Contributors.
 * 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://eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   John Kew (vmware)         	initial implementation
 *   Lyor Goldstein (vmware)	add support for weaved class being re-defined
 *******************************************************************************/
package org.aspectj.weaver.tools.cache;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

Useful "common" functionality for caching to files 
/**
 * Useful "common" functionality for caching to files 
 */
public abstract class AbstractFileCacheBacking extends AbstractCacheBacking {
	
Default property used to specify a default weaving cache dir location
/**
	 * Default property used to specify a default weaving cache dir location
	 */
	public static final String WEAVED_CLASS_CACHE_DIR = "aj.weaving.cache.dir";
	private final File cacheDirectory;

	protected AbstractFileCacheBacking (File cacheDirectory) {
        if ((this.cacheDirectory=cacheDirectory) == null) {
            throw new IllegalStateException("No cache directory specified");
        }
	}

    public File getCacheDirectory () {
        return cacheDirectory;
    }

    protected void writeClassBytes (String key, byte[] bytes) throws Exception {
        File    dir=getCacheDirectory(), file=new File(dir, key);
        FileOutputStream    out=new FileOutputStream(file);
        try {
            out.write(bytes);
        } finally {
        	close(out, file);
        }
    }

	protected void delete(File file) {
		if (file.exists() && (!file.delete())) {
			if ((logger != null) && logger.isTraceEnabled()) {
				logger.error("Error deleting file " + file.getAbsolutePath());
			}
		}
	}

	protected void close(OutputStream out, File file) {
		if (out != null) {
			try {
				out.close();
			} catch (IOException e) {
				if ((logger != null) && logger.isTraceEnabled()) {
					logger.error("Failed (" + e.getClass().getSimpleName() + ")"
							   + " to close write file " + file.getAbsolutePath()
							   + ": " + e.getMessage(), e);
				}
			}
		}
	}

	protected void close(InputStream in, File file) {
		if (in != null) {
			try {
				in.close();
			} catch (IOException e) {
				if ((logger != null) && logger.isTraceEnabled()) {
					logger.error("Failed (" + e.getClass().getSimpleName() + ")"
							   + " to close read file " + file.getAbsolutePath()
							   + ": " + e.getMessage(), e);
				}
			}
		}
	}
}