Zip URLConnection
/**
* The utillib library.
* More information is available at http://www.jinchess.com/.
* Copyright (C) 2003 Alexander Maryanovsky.
* All rights reserved.
*
* The utillib library is free software; you can redistribute
* it and/or modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* The utillib library is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with utillib library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.net.URL;
import java.net.URLConnection;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipFile;
import java.util.zip.ZipEntry;
/**
* A <code>URLConnection</code> which loads its content from a specified zip
* entry within a local file.
*/
public class ZipURLConnection extends URLConnection{
/**
* The zip file.
*/
private final File file;
/**
* The name of the zip entry within the zip file.
*/
private final String zipEntryName;
/**
* The <code>ZipFile</code> object for the zip file. Created when
* <code>connect()</code> is called.
*/
private ZipFile zipFile = null;
/**
* The <code>ZipEntry</code> object for the entry in the zip file. Created
* when <code>connect()</code> is called.
*/
private ZipEntry zipEntry = null;
/**
* Creates a new <code>ZipURLConnection</code> for the specified zip entry
* within the specified <code>File</code>.
*/
public ZipURLConnection(URL url, File file, String zipEntryName){
super(url);
this.file = file;
this.zipEntryName = zipEntryName;
}
/**
* Attempts to open the zip entry.
*/
public void connect() throws IOException{
this.zipFile = new ZipFile(file);
this.zipEntry = zipFile.getEntry(zipEntryName);
if (zipEntry == null)
throw new IOException("Entry " + zipEntryName + " not found in file " + file);
this.connected = true;
}
/**
* Returns the <code>InputStream</code> that reads from this connection.
*/
public InputStream getInputStream() throws IOException{
if (!connected)
connect();
return zipFile.getInputStream(zipEntry);
}
/**
* Returns the length of the uncompressed zip entry.
*/
public int getContentLength(){
if (!connected)
return -1;
return (int)zipEntry.getSize();
}
}
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