Spring Framework example source code file (Resource.java)

This example Spring Framework source code file (Resource.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 - Spring Framework tags/keywords

file, inputstreamsource, inputstreamsource, io, ioexception, ioexception, net, network, resource, resource, string, string, uri, url

The Spring Framework Resource.java source code

/*
 * Copyright 2002-2008 the original author or authors.
 *
 * 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.springframework.core.io;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URL;

/**
 * Interface for a resource descriptor that abstracts from the actual
 * type of underlying resource, such as a file or class path resource.
 *
 * <p>An InputStream can be opened for every resource if it exists in
 * physical form, but a URL or File handle can just be returned for
 * certain resources. The actual behavior is implementation-specific.
 *
 * @author Juergen Hoeller
 * @since 28.12.2003
 * @see #getInputStream()
 * @see #getURL()
 * @see #getURI()
 * @see #getFile()
 * @see FileSystemResource
 * @see ClassPathResource
 * @see UrlResource
 * @see ByteArrayResource
 * @see InputStreamResource
 * @see org.springframework.web.context.support.ServletContextResource
 */
public interface Resource extends InputStreamSource {

	/**
	 * Return whether this resource actually exists in physical form.
	 * <p>This method performs a definitive existence check, whereas the
	 * existence of a <code>Resource handle only guarantees a
	 * valid descriptor handle.
	 */
	boolean exists();

	/**
	 * Return whether the contents of this resource can be read,
	 * e.g. via {@link #getInputStream()} or {@link #getFile()}.
	 * <p>Will be true for typical resource descriptors;
	 * note that actual content reading may still fail when attempted.
	 * However, a value of <code>false is a definitive indication
	 * that the resource content cannot be read.
	 */
	boolean isReadable();

	/**
	 * Return whether this resource represents a handle with an open
	 * stream. If true, the InputStream cannot be read multiple times,
	 * and must be read and closed to avoid resource leaks.
	 * <p>Will be false for typical resource descriptors.
	 */
	boolean isOpen();

	/**
	 * Return a URL handle for this resource.
	 * @throws IOException if the resource cannot be resolved as URL,
	 * i.e. if the resource is not available as descriptor
	 */
	URL getURL() throws IOException;

	/**
	 * Return a URI handle for this resource.
	 * @throws IOException if the resource cannot be resolved as URI,
	 * i.e. if the resource is not available as descriptor
	 */
	URI getURI() throws IOException;

	/**
	 * Return a File handle for this resource.
	 * @throws IOException if the resource cannot be resolved as absolute
	 * file path, i.e. if the resource is not available in a file system
	 */
	File getFile() throws IOException;

	/**
	 * Determine the last-modified timestamp for this resource.
	 * @throws IOException if the resource cannot be resolved
	 * (in the file system or as some other known physical resource type)
	 */
	long lastModified() throws IOException;

	/**
	 * Create a resource relative to this resource.
	 * @param relativePath the relative path (relative to this resource)
	 * @return the resource handle for the relative resource
	 * @throws IOException if the relative resource cannot be determined
	 */
	Resource createRelative(String relativePath) throws IOException;

	/**
	 * Return a filename for this resource, i.e. typically the last
	 * part of the path: for example, "myfile.txt".
	 */
	String getFilename();

	/**
	 * Return a description for this resource,
	 * to be used for error output when working with the resource.
	 * <p>Implementations are also encouraged to return this value
	 * from their <code>toString method.
	 * @see java.lang.Object#toString()
	 */
	String getDescription();

}