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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.xbean.classloader;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.cert.Certificate;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

/**
 * This is a handle (a connection) to some resource, which may be a class, native library, text file, image, etc.
 * Handles are returned by a ResourceFinder. A resource handle allows easy access to the resource data (using methods
 * {@link #getInputStream} or {@link #getBytes}) as well as access resource metadata, such as attributes, certificates,
 * etc.
 * 
 * As soon as the handle is no longer in use, it should be explicitly {@link #close}d, similarly to I/O streams.
 * 
 * @author Dain Sundstrom
 */
public interface ResourceHandle {

	/**
	 * @return the name of the resource. The name is a "/"-separated path name that identifies the resource.
	 */
	String getName();

	/**
	 * @return the URL of the resource.
	 */
	URL getUrl();

	/**
	 * Does this resource refer to a directory. Directory resources are commly used as the basis for a URL in client
	 * application. A directory resource has 0 bytes for it's content.
	 * @return true if the resource referes to a directory
	 */
	boolean isDirectory();

	/**
	 * @return the CodeSource URL for the class or resource.
	 */
	URL getCodeSourceUrl();

	/**
	 * @return and InputStream for reading this resource data.
	 * @throws IOException
	 */
	InputStream getInputStream() throws IOException;

	/**
	 * @return the length of this resource data, or -1 if unknown.
	 */
	int getContentLength();

	/**
	 * @return this resource data as an array of bytes.
	 * @throws IOException
	 */
	byte[] getBytes() throws IOException;

	/**
	 * @return the Manifest of the JAR file from which this resource was loaded, or null if none.
	 * @throws IOException
	 */
	Manifest getManifest() throws IOException;

	/**
	 * @return the Certificates of the resource, or null if none.
	 */
	Certificate[] getCertificates();

	/**
	 * @return the Attributes of the resource, or null if none.
	 * @throws IOException
	 */
	Attributes getAttributes() throws IOException;

	/**
	 * Closes a connection to the resource identified by this handle. Releases any I/O objects associated with the
	 * handle.
	 */
	void close();
}