Spring Framework example source code file (InputStreamResource.java)

This example Spring Framework source code file (InputStreamResource.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

abstractresource, illegalargumentexception, illegalstateexception, illegalstateexception, inputstream, inputstream, inputstreamresource, inputstreamresource, io, ioexception, string, string

The Spring Framework InputStreamResource.java source code

/*
 * Copyright 2002-2006 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.IOException;
import java.io.InputStream;

/**
 * {@link Resource} implementation for a given InputStream. Should only
 * be used if no specific Resource implementation is applicable.
 * In particular, prefer {@link ByteArrayResource} or any of the
 * file-based Resource implementations where possible.
 *
 * <p>In contrast to other Resource implementations, this is a descriptor
 * for an <i>already opened resource - therefore returning "true" from
 * <code>isOpen(). Do not use it if you need to keep the resource
 * descriptor somewhere, or if you need to read a stream multiple times.
 *
 * @author Juergen Hoeller
 * @since 28.12.2003
 * @see ByteArrayResource
 * @see ClassPathResource
 * @see FileSystemResource
 * @see UrlResource
 */
public class InputStreamResource extends AbstractResource {

	private final InputStream inputStream;

	private final String description;

	private boolean read = false;


	/**
	 * Create a new InputStreamResource.
	 * @param inputStream the InputStream to use
	 */
	public InputStreamResource(InputStream inputStream) {
		this(inputStream, "resource loaded through InputStream");
	}

	/**
	 * Create a new InputStreamResource.
	 * @param inputStream the InputStream to use
	 * @param description where the InputStream comes from
	 */
	public InputStreamResource(InputStream inputStream, String description) {
		if (inputStream == null) {
			throw new IllegalArgumentException("InputStream must not be null");
		}
		this.inputStream = inputStream;
		this.description = (description != null ? description : "");
	}


	/**
	 * This implementation always returns <code>true.
	 */
	public boolean exists() {
		return true;
	}

	/**
	 * This implementation always returns <code>true.
	 */
	public boolean isOpen() {
		return true;
	}

	/**
	 * This implementation throws IllegalStateException if attempting to
	 * read the underlying stream multiple times.
	 */
	public InputStream getInputStream() throws IOException, IllegalStateException {
		if (this.read) {
			throw new IllegalStateException("InputStream has already been read - " +
					"do not use InputStreamResource if a stream needs to be read multiple times");
		}
		this.read = true;
		return this.inputStream;
	}

	/**
	 * This implementation returns the passed-in description, if any.
	 */
	public String getDescription() {
		return this.description;
	}


	/**
	 * This implementation compares the underlying InputStream.
	 */
	public boolean equals(Object obj) {
		return (obj == this ||
		    (obj instanceof InputStreamResource && ((InputStreamResource) obj).inputStream.equals(this.inputStream)));
	}

	/**
	 * This implementation returns the hash code of the underlying InputStream.
	 */
	public int hashCode() {
		return this.inputStream.hashCode();
	}

}