net.lightbody.bmp.proxy.jetty.util.URLResource.java Source code

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Here is the source code for net.lightbody.bmp.proxy.jetty.util.URLResource.java

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// ========================================================================
// $Id: URLResource.java,v 1.9 2005/08/13 00:01:28 gregwilkins Exp $
// Copyright 1996-2004 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 net.lightbody.bmp.proxy.jetty.util;

import net.lightbody.bmp.proxy.jetty.log.LogFactory;
import org.apache.commons.logging.Log;

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;

/* ------------------------------------------------------------ */
/** Abstract resource class.
 *
 * @version $Id: URLResource.java,v 1.9 2005/08/13 00:01:28 gregwilkins Exp $
 * @author Nuno Preguia
 * @author Greg Wilkins (gregw)
 */
public class URLResource extends Resource {
    private static Log log = LogFactory.getLog(URLResource.class);

    protected URL _url;
    protected String _urlString;
    protected transient URLConnection _connection;
    protected transient InputStream _in = null;

    /* ------------------------------------------------------------ */
    protected URLResource(URL url, URLConnection connection) {
        _url = url;
        _urlString = _url.toString();
        _connection = connection;
    }

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

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

        return newResource(URI.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);
    }

}