/*
 * Copyright 2002-2016 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
 *
 *      https://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.mock.web;

import java.io.IOException;
import java.io.OutputStream;

import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;

import org.springframework.util.Assert;

/**
 * Delegating implementation of {@link javax.servlet.ServletOutputStream}.
 *
 * <p>Used by {@link MockHttpServletResponse}; typically not directly
 * used for testing application controllers.
 *
 * @author Juergen Hoeller
 * @since 1.0.2
 * @see MockHttpServletResponse
 */
public class DelegatingServletOutputStream extends ServletOutputStream {

	private final OutputStream targetStream;


	/**
	 * Create a DelegatingServletOutputStream for the given target stream.
	 * @param targetStream the target stream (never {@code null})
	 */
	public DelegatingServletOutputStream(OutputStream targetStream) {
		Assert.notNull(targetStream, "Target OutputStream must not be null");
		this.targetStream = targetStream;
	}

	/**
	 * Return the underlying target stream (never {@code null}).
	 */
	public final OutputStream getTargetStream() {
		return this.targetStream;
	}


	@Override
	public void write(int b) throws IOException {
		this.targetStream.write(b);
	}

	@Override
	public void flush() throws IOException {
		super.flush();
		this.targetStream.flush();
	}

	@Override
	public void close() throws IOException {
		super.close();
		this.targetStream.close();
	}

	@Override
	public boolean isReady() {
		return true;
	}

	@Override
	public void setWriteListener(WriteListener writeListener) {
		throw new UnsupportedOperationException();
	}

}
