Mega Code Archive
Zip URLStream Handler
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/**
* 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.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
/**
* <p>A URLStreamHandler which allows accessing specific zip entries within a
* zip file. The format of the file part of the URL is
* <code>[full path to the zip file]|[name of zip entry]</code>, but you are
* encouraged to use the
* <code>createURL(String fileName, String entryName)</code> method
* instead of creating a URL manually. The host and port part of the URL should
* be <code>null</code>. An application is responsible for setting a
* <code>URLStreamHandlerFactory</code> that will return a ZipURLStreamHandler
* when appropriate.
*/
public class ZipURLStreamHandler extends URLStreamHandler{
/**
* Returns a ZipURLConnection for the specified URL.
*/
public URLConnection openConnection(URL url) throws IOException{
String urlFile = url.getFile();
int barIndex = urlFile.indexOf("|");
if (barIndex == -1)
throw new MalformedURLException("Missing '|'");
String fileName = urlFile.substring(0, barIndex);
String entryName = urlFile.substring(barIndex + 1);
return new ZipURLConnection(url, new File(fileName), entryName);
}
/**
* Parses the specified URL string.
*/
protected void parseURL(URL url, String spec, int start, int limit){
String urlFile = url.getFile();
int barIndex = urlFile.indexOf("|");
String fileName = barIndex == -1 ? urlFile : urlFile.substring(0, barIndex);
String entryName = barIndex == -1 ? "" : urlFile.substring(barIndex + 1);
int lastSlashIndex = entryName.lastIndexOf("/");
String newEntryName = entryName.substring(0, lastSlashIndex + 1) + spec.substring(start, limit);
setURL(url, url.getProtocol(), "", -1, fileName + "|" + newEntryName, null);
}
/**
* Creates a <code>URL</code> that points to the specified entry within the
* specified zip file. The <code>URL</code> will have "zip" as the protocol
* name. To use the resulting <code>URL</code>, an application must set
* a <code>URLStreamHandlerFactory</code> (via the <code>URL</code> class)
* which will return a <code>ZipURLStreamHandler</code> for the "zip"
* protocol. Returns <code>null</code> if the "zip: protocol is unrecognized.
*/
public static URL createURL(String fileName, String entryName){
return createURL("zip", fileName, entryName);
}
/**
* Creates a <code>URL</code> that points to the specified entry within the
* specified zip file and has the specified protocol name. To use the
* resulting <code>URL</code>, an application must set a
* <code>URLStreamHandlerFactory</code> (via the <code>URL</code> class)
* which will return a <code>ZipURLStreamHandler</code> for the protocol name
* given to this method. Returns <code>null</code> if the specified protocol
* is unrecognized.
*/
public static URL createURL(String protocol, String fileName, String entryName){
try{
return new URL(protocol, "", -1, fileName + "|" + entryName);
} catch (MalformedURLException e){
e.printStackTrace();
return null;
}
}
}
/**
* 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
*/
/**
* A <code>URLConnection</code> which loads its content from a specified zip
* entry within a local file.
*/
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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