Stream input channel

StreamInputChannel3.java

/*
 * JBoss, Home of Professional Open Source
 *
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * 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 io.examples.example1;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

import io.examples.IoCallback2;

/**
 * @author <a href="mailto:david.lloyd@redhat.com">David M. Lloyd</a>
 */
public interface StreamInputChannel3 extends AsynchronousChannel3 {

    /**
     * Get the number of bytes consumed by this channel over all time.  This includes buffered bytes which have not
     * yet been dequeued.
     *
     * @return the number of bytes ever consumed by this channel
     */
    long getByteCounter();

    /**
     *
     * @param channel
     * @param length
     * @param callback
     */
    default void transferTo(StreamOutputChannel3 channel, long length, IoCallback2<?> callback) {
        transferTo(channel, length, callback, null);
    }

    default <T> void transferTo(StreamOutputChannel3 channel, long length, IoCallback2<T> callback, T attachment) {
        channel.transferFrom(this, length, callback, attachment);
    }

    default void transferTo(FileChannel channel, long length, IoCallback2<?> callback) {
        transferTo(channel, length, callback, null);
    }

    <T> void transferTo(FileChannel channel, long length, IoCallback2<T> callback, T attachment);

    default void skip(long length, IoCallback2<?> callback) {
        skip(length, callback, null);
    }

    <T> void skip(long length, IoCallback2<T> callback, T attachment);

    long skipBlocking(long length) throws IOException;

    /**
     * Initiate a read operation, calling the given callback once a certain number of bytes have been read.  Use
     * {@link #checkResult()} to acquire the thrown exception and {@link #peekBuffer()} or {@link #getBuffer()}
     * to examine the result of the read operation.
     * <p>
     * The read operation will not trigger the callback until at least {@code minLength} bytes are available or an error
     * occurs.  The operation will not attempt to make more than {@code maxLength} bytes available.  The value of
     * {@code maxLength} must be equal to or greater than the value of {@code minLength}.
     * <p>
     * The channel is not thread-safe, and thus should not be accessed until the callback has been called.
     *
     * @param minLength the minimum number of available bytes before returning
     * @param maxLength the maximum number of bytes to make available
     * @param callback the callback to call when the read operation is complete (or an error occurs)
     * @param attachment the attachment to pass to the callback
     * @param <T> the attachment type
     */
    <T> void read(int minLength, int maxLength, IoCallback2<T> callback, T attachment);

    default void read(int minLength, int maxLength, IoCallback2<?> callback) {
        read(minLength, maxLength, callback, null);
    }

    default <T> void read(int minLength, IoCallback2<T> callback, T attachment) {
        read(minLength, Integer.MAX_VALUE, callback, attachment);
    }

    default void read(int minLength, IoCallback2<?> callback) {
        read(minLength, callback, null);
    }

    default <T> void read(IoCallback2<T> callback, T attachment) {
        read(0, callback, attachment);
    }

    default void read(IoCallback2<?> callback) {
        read(0, callback, null);
    }

    /**
     * Get an input stream for this channel.
     *
     * @return the input stream
     */
    ChannelInputStream getInputStream();

    /**
     * Get the number of buffered bytes available on this channel.
     *
     * @return the number of available bytes
     */
    long available();

    /**
     * Get a peek at the first buffer of the channel, if any.  Any emptied buffers at the head of the queue will
     * automatically be released.
     *
     * @return the buffer, or {@code null} if no buffers are in the queue
     */
    ByteBuffer peekBuffer();

    /**
     * Get and remove the first buffer of the channel, if any.
     *
     * @return the buffer, or {@code null} if no buffers are in the queue
     */
    ByteBuffer getBuffer();
}