my-jdk/jdkSrc/jdk8/sun/rmi/transport/proxy/HttpSendInputStream.java

/*
 * Copyright (c) 1996, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package sun.rmi.transport.proxy;

import java.io.*;

/**
 * The HttpSendInputStream class is used by the HttpSendSocket class as
 * a layer on the top of the InputStream it returns so that it can be
 * notified of attempts to read from it.  This allows the HttpSendSocket
 * to know when it should push across its output message.
 */
class HttpSendInputStream extends FilterInputStream {

    /** the HttpSendSocket object that is providing this stream */
    HttpSendSocket owner;

    /**
     * Create new filter on a given input stream.
     * @param in the InputStream to filter from
     * @param owner the HttpSendSocket that is providing this stream
     */
    public HttpSendInputStream(InputStream in, HttpSendSocket owner)
        throws IOException
    {
        super(in);

        this.owner = owner;
    }

    /**
     * Mark this stream as inactive for its owner socket, so the next time
     * a read is attempted, the owner will be notified and a new underlying
     * input stream obtained.
     */
    public void deactivate()
    {
        in = null;
    }

    /**
     * Read a byte of data from the stream.
     */
    public int read() throws IOException
    {
        if (in == null)
            in = owner.readNotify();
        return in.read();
    }

    /**
     * Read into an array of bytes.
     * @param b the buffer into which the data is to be read
     * @param off the start offset of the data
     * @param len the maximum number of bytes to read
     */
    public int read(byte b[], int off, int len) throws IOException
    {
        if (len == 0)
            return 0;
        if (in == null)
            in = owner.readNotify();
        return in.read(b, off, len);
    }

    /**
     * Skip bytes of input.
     * @param n the number of bytes to be skipped
     */
    public long skip(long n) throws IOException
    {
        if (n == 0)
            return 0;
        if (in == null)
            in = owner.readNotify();
        return in.skip(n);
    }

    /**
     * Return the number of bytes that can be read without blocking.
     */
    public int available() throws IOException
    {
        if (in == null)
            in = owner.readNotify();
        return in.available();
    }

    /**
     * Close the stream.
     */
    public void close() throws IOException
    {
        owner.close();
    }

    /**
     * Mark the current position in the stream.
     * @param readlimit how many bytes can be read before mark becomes invalid
     */
    public synchronized void mark(int readlimit)
    {
        if (in == null) {
            try {
                in = owner.readNotify();
            }
            catch (IOException e) {
                return;
            }
        }
        in.mark(readlimit);
    }

    /**
     * Reposition the stream to the last marked position.
     */
    public synchronized void reset() throws IOException
    {
        if (in == null)
            in = owner.readNotify();
        in.reset();
    }

    /**
     * Return true if this stream type supports mark/reset.
     */
    public boolean markSupported()
    {
        if (in == null) {
            try {
                in = owner.readNotify();
            }
            catch (IOException e) {
                return false;
            }
        }
        return in.markSupported();
    }
}