/*
 * Copyright 2002-2018 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.InputStream;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;

import org.springframework.util.Assert;

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

	private final InputStream sourceStream;

	private boolean finished = false;


	/**
	 * Create a DelegatingServletInputStream for the given source stream.
	 * @param sourceStream the source stream (never {@code null})
	 */
	public DelegatingServletInputStream(InputStream sourceStream) {
		Assert.notNull(sourceStream, "Source InputStream must not be null");
		this.sourceStream = sourceStream;
	}

	/**
	 * Return the underlying source stream (never {@code null}).
	 */
	public final InputStream getSourceStream() {
		return this.sourceStream;
	}


	@Override
	public int read() throws IOException {
		int data = this.sourceStream.read();
		if (data == -1) {
			this.finished = true;
		}
		return data;
	}

	@Override
	public int available() throws IOException {
		return this.sourceStream.available();
	}

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

	@Override
	public boolean isFinished() {
		return this.finished;
	}

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

	@Override
	public void setReadListener(ReadListener readListener) {
		throw new UnsupportedOperationException();
	}

}
