001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.xbean.classloader;
018
019import java.net.URL;
020import java.io.InputStream;
021import java.io.IOException;
022import java.util.jar.Manifest;
023import java.util.jar.Attributes;
024import java.security.cert.Certificate;
025
026/**
027 * This is a handle (a connection) to some resource, which may
028 * be a class, native library, text file, image, etc. Handles are returned
029 * by a ResourceFinder. A resource handle allows easy access to the resource data
030 * (using methods {@link #getInputStream} or {@link #getBytes}) as well as
031 * access resource metadata, such as attributes, certificates, etc.
032 * <p/>
033 * As soon as the handle is no longer in use, it should be explicitly
034 * {@link #close}d, similarly to I/O streams.
035 *
036 * @version $Rev: 437551 $ $Date: 2006-08-28 08:14:47 +0200 (lun. 28 ao?t 2006) $
037 */
038public interface ResourceHandle {
039    /**
040     * Return the name of the resource. The name is a "/"-separated path
041     * name that identifies the resource.
042     */
043    String getName();
044
045    /**
046     * Returns the URL of the resource.
047     */
048    URL getUrl();
049
050    /**
051     * Does this resource refer to a directory.  Directory resources are commly used
052     * as the basis for a URL in client application.  A directory resource has 0 bytes for it's content. 
053     */
054    boolean isDirectory();
055
056    /**
057     * Returns the CodeSource URL for the class or resource.
058     */
059    URL getCodeSourceUrl();
060
061    /**
062     * Returns and InputStream for reading this resource data.
063     */
064    InputStream getInputStream() throws IOException;
065
066    /**
067     * Returns the length of this resource data, or -1 if unknown.
068     */
069    int getContentLength();
070
071    /**
072     * Returns this resource data as an array of bytes.
073     */
074    byte[] getBytes() throws IOException;
075
076    /**
077     * Returns the Manifest of the JAR file from which this resource
078     * was loaded, or null if none.
079     */
080    Manifest getManifest() throws IOException;
081
082    /**
083     * Return the Certificates of the resource, or null if none.
084     */
085    Certificate[] getCertificates();
086
087    /**
088     * Return the Attributes of the resource, or null if none.
089     */
090    Attributes getAttributes() throws IOException;
091
092    /**
093     * Closes a connection to the resource indentified by this handle. Releases
094     * any I/O objects associated with the handle.
095     */
096    void close();
097}