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Jetty example source code file (URLResource.java)

This example Jetty source code file (URLResource.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Jetty tags/keywords

file, inputstream, io, ioexception, ioexception, ioexception,malformedurlexception, net, network, resource, security, securityexception, securityexception, string, string, url, urlconnection, urlresource, urlresource

The Jetty URLResource.java source code

// ========================================================================
// Copyright 1996-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at 
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ========================================================================
package org.mortbay.resource;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.security.Permission;

import org.mortbay.log.Log;
import org.mortbay.util.URIUtil;

/* ------------------------------------------------------------ */
/** Abstract resource class.
 *
 * @author Nuno Pregui�a
 * @author Greg Wilkins (gregw)
 */
public class URLResource extends Resource
{

    
    protected URL _url;
    protected String _urlString;
    protected transient URLConnection _connection;
    protected transient InputStream _in=null;
    transient boolean _useCaches = Resource.__defaultUseCaches;
    
    /* ------------------------------------------------------------ */
    protected URLResource(URL url, URLConnection connection)
    {
        _url = url;
        _urlString=_url.toString();
        _connection=connection;
    }
    
    protected URLResource (URL url, URLConnection connection, boolean useCaches)
    {
        this (url, connection);
        _useCaches = useCaches;
    }

    /* ------------------------------------------------------------ */
    protected synchronized boolean checkConnection()
    {
        if (_connection==null)
        {
            try{
                _connection=_url.openConnection();
                _connection.setUseCaches(_useCaches);
            }
            catch(IOException e)
            {
                Log.ignore(e);
            }
        }
        return _connection!=null;
    }

    /* ------------------------------------------------------------ */
    /** Release any resources held by the resource.
     */
    public synchronized void release()
    {
        if (_in!=null)
        {
            try{_in.close();}catch(IOException e){Log.ignore(e);}
            _in=null;
        }

        if (_connection!=null)
            _connection=null;
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns true if the respresened resource exists.
     */
    public boolean exists()
    {
        try
        {
            synchronized(this)
            {
                if (checkConnection() && _in==null )
                    _in = _connection.getInputStream();
            }
        }
        catch (IOException e)
        {
            Log.ignore(e);
        }
        return _in!=null;
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns true if the respresenetd resource is a container/directory.
     * If the resource is not a file, resources ending with "/" are
     * considered directories.
     */
    public boolean isDirectory()
    {
        return exists() && _url.toString().endsWith("/");
    }


    /* ------------------------------------------------------------ */
    /**
     * Returns the last modified time
     */
    public long lastModified()
    {
        if (checkConnection())
            return _connection.getLastModified();
        return -1;
    }


    /* ------------------------------------------------------------ */
    /**
     * Return the length of the resource
     */
    public long length()
    {
        if (checkConnection())
            return _connection.getContentLength();
        return -1;
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns an URL representing the given resource
     */
    public URL getURL()
    {
        return _url;
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns an File representing the given resource or NULL if this
     * is not possible.
     */
    public File getFile()
        throws IOException
    {
        // Try the permission hack
        if (checkConnection())
        {
            Permission perm = _connection.getPermission();
            if (perm instanceof java.io.FilePermission)
                return new File(perm.getName());
        }

        // Try the URL file arg
        try {return new File(_url.getFile());}
        catch(Exception e) {Log.ignore(e);}

        // Don't know the file
        return null;    
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns the name of the resource
     */
    public String getName()
    {
        return _url.toExternalForm();
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns an input stream to the resource
     */
    public synchronized InputStream getInputStream()
        throws java.io.IOException
    {
        if (!checkConnection())
            throw new IOException( "Invalid resource");

        try
        {    
            if( _in != null)
            {
                InputStream in = _in;
                _in=null;
                return in;
            }
            return _connection.getInputStream();
        }
        finally
        {
            _connection=null;
        }
    }


    /* ------------------------------------------------------------ */
    /**
     * Returns an output stream to the resource
     */
    public OutputStream getOutputStream()
        throws java.io.IOException, SecurityException
    {
        throw new IOException( "Output not supported");
    }

    /* ------------------------------------------------------------ */
    /**
     * Deletes the given resource
     */
    public boolean delete()
        throws SecurityException
    {
        throw new SecurityException( "Delete not supported");
    }

    /* ------------------------------------------------------------ */
    /**
     * Rename the given resource
     */
    public boolean renameTo( Resource dest)
        throws SecurityException
    {
        throw new SecurityException( "RenameTo not supported");
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns a list of resource names contained in the given resource
     */
    public String[] list()
    {
        return null;
    }

    /* ------------------------------------------------------------ */
    /**
     * Returns the resource contained inside the current resource with the
     * given name
     */
    public Resource addPath(String path)
        throws IOException,MalformedURLException
    {
        if (path==null)
            return null;

        path = URIUtil.canonicalPath(path);

        return newResource(URIUtil.addPaths(_url.toExternalForm(),path));
    }

    /* ------------------------------------------------------------ */
    public String toString()
    {
        return _urlString;
    }

    /* ------------------------------------------------------------ */
    public int hashCode()
    {
        return _url.hashCode();
    }
    
    /* ------------------------------------------------------------ */
    public boolean equals( Object o)
    {
        return o instanceof URLResource &&
            _url.equals(((URLResource)o)._url);
    }

    public boolean getUseCaches ()
    {
        return _useCaches;
    }
}

Other Jetty examples (source code examples)

Here is a short list of links related to this Jetty URLResource.java source code file:

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