com.noelios.restlet.http.InputEntityStream Maven / Gradle / Ivy

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This OSGi bundle wraps org.restlet, and com.noelios.restlet ${pkgVersion} jar files.
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/**
 * Copyright 2005-2008 Noelios Technologies.
 * 
 * The contents of this file are subject to the terms of the following open
 * source licenses: LGPL 3.0 or LGPL 2.1 or CDDL 1.0 (the "Licenses"). You can
 * select the license that you prefer but you may not use this file except in
 * compliance with one of these Licenses.
 * 
 * You can obtain a copy of the LGPL 3.0 license at
 * http://www.gnu.org/licenses/lgpl-3.0.html
 * 
 * You can obtain a copy of the LGPL 2.1 license at
 * http://www.gnu.org/licenses/lgpl-2.1.html
 * 
 * You can obtain a copy of the CDDL 1.0 license at
 * http://www.sun.com/cddl/cddl.html
 * 
 * See the Licenses for the specific language governing permissions and
 * limitations under the Licenses.
 * 
 * Alternatively, you can obtain a royaltee free commercial license with less
 * limitations, transferable or non-transferable, directly at
 * http://www.noelios.com/products/restlet-engine
 * 
 * Restlet is a registered trademark of Noelios Technologies.
 */

package com.noelios.restlet.http;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Input stream based on a source stream that must only be partially read.
 */
public class InputEntityStream extends FilterInputStream {

    /** The total size that should be read from the source stream. */
    private volatile long availableSize;

    /** The total size when the {@link #mark(int)} method was called. */
    private volatile long markedAvailableSize;

    /**
     * Constructor.
     * 
     * @param source
     *            The source stream.
     * @param size
     *            The total size that should be read from the source stream.
     */
    public InputEntityStream(InputStream source, long size) {
        super(source);
        this.availableSize = size;
        this.markedAvailableSize = -1;
    }

    @Override
    public int available() throws IOException {
        return Math.min((int) this.availableSize, super.available());
    }

    @Override
    public void close() throws IOException {
        // Don't close it directly
    }

    @Override
    public synchronized void mark(int readlimit) {
        if (markSupported()) {
            this.markedAvailableSize = availableSize;
        }

        super.mark(readlimit);
    }

    /**
     * Reads a byte from the underlying stream.
     * 
     * @return The byte read, or -1 if the end of the stream has been reached.
     */
    @Override
    public int read() throws IOException {
        int result = -1;

        if (this.availableSize > 0) {
            result = super.in.read();

            if (result != -1) {
                this.availableSize--;
            }
        }

        return result;
    }

    @Override
    public int read(byte b[], int off, int len) throws IOException {
        int result = -1;

        if (this.availableSize > 0) {
            result = super.in.read(b, off, Math.min(len,
                    (int) this.availableSize));

            if (result > 0) {
                this.availableSize -= result;
            }
        }

        return result;
    }

    @Override
    public synchronized void reset() throws IOException {
        if (markSupported()) {
            if (this.markedAvailableSize != -1) {
                this.availableSize = markedAvailableSize;
                this.markedAvailableSize = -1;
            }
        }

        super.reset();
    }

}