LazyTrueZipEntryStream.java

package org.rr.commons.utils.compression.truezip;

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

import org.apache.commons.io.IOUtils;
import org.rr.commons.mufs.IResourceHandler;
import org.rr.commons.utils.compression.CompressedDataEntry;

public class LazyTrueZipEntryStream extends InputStream {

	private IResourceHandler zipResource;
	private String entry;
	private InputStream data;
	
	public LazyTrueZipEntryStream(IResourceHandler zipResource, String entry) {
		this.zipResource = zipResource;
		this.entry = entry;
	}
	
	private void load() throws IOException {
		if(data == null) {
			InputStream contentInputStream = null;
			try {
				CompressedDataEntry extract = TrueZipUtils.extract(zipResource, entry);
				data = new ByteArrayInputStream(extract.getBytes());
				data.mark(Integer.MAX_VALUE);
			} finally {
				if(contentInputStream != null) {
					IOUtils.closeQuietly(contentInputStream);
				}
			}
		}		
	}
	
	@Override
	public int read() throws IOException {
		load();
		return data.read();
	}

	@Override
	public int read(byte[] b, int off, int len) throws IOException {
		load();
		return data.read(b, off, len);
	}

	@Override
	public int available() throws IOException {
		load();
		return data.available();
	}

	@Override
	public void close() throws IOException {
		if(data != null) {
			data.close();
			data = null;
		}
	}

	@Override
	public synchronized void mark(int readlimit) {
		if(data != null) {
			data.mark(readlimit);
		}
	}

	@Override
	public boolean markSupported() {
		return true;
	}

	@Override
	public synchronized void reset() throws IOException {
		if(data != null) {
			data.reset();
		}
	}
	
}