org.apache.http.impl.nio.codecs.AbstractContentDecoder Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of com.liferay.petra.json.web.service.client Show documentation
Liferay Petra JSON Web Service Client
The newest version!
/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 *
 */

package org.apache.http.impl.nio.codecs;

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

import org.apache.http.impl.io.HttpTransportMetricsImpl;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.reactor.SessionInputBuffer;
import org.apache.http.util.Args;

/**
 * Abstract {@link ContentDecoder} that serves as a base for all content
 * decoder implementations.
 *
 * @since 4.0
 */
public abstract class AbstractContentDecoder implements ContentDecoder {

    protected final ReadableByteChannel channel;
    protected final SessionInputBuffer buffer;
    protected final HttpTransportMetricsImpl metrics;

    protected boolean completed;

    /**
     * Creates an instance of this class.
     *
     * @param channel the source channel.
     * @param buffer the session input buffer that can be used to store
     *    session data for intermediate processing.
     * @param metrics Transport metrics of the underlying HTTP transport.
     */
    public AbstractContentDecoder(
            final ReadableByteChannel channel,
            final SessionInputBuffer buffer,
            final HttpTransportMetricsImpl metrics) {
        super();
        Args.notNull(channel, "Channel");
        Args.notNull(buffer, "Session input buffer");
        Args.notNull(metrics, "Transport metrics");
        this.buffer = buffer;
        this.channel = channel;
        this.metrics = metrics;
    }

    @Override
    public boolean isCompleted() {
        return this.completed;
    }

    /**
     * Sets the completed status of this decoder. Normally this is not necessary
     * (the decoder will automatically complete when the underlying channel
     * returns EOF). It is useful to mark the decoder as completed if you have
     * some other means to know all the necessary data has been read and want to
     * reuse the underlying connection for more messages.
     *
     * @param completed the completed status of this decoder.
     * @since 4.4.11
     */
    public void setCompleted(final boolean completed) {
        this.completed = completed;
    }

    /**
     * Sets the completed status of this decoder to true. Normally this is not necessary
     * (the decoder will automatically complete when the underlying channel
     * returns EOF). It is useful to mark the decoder as completed if you have
     * some other means to know all the necessary data has been read and want to
     * reuse the underlying connection for more messages.
     *
     * @since 4.4.11
     */
    protected void setCompleted() {
        this.completed = true;
    }

    /**
     * Reads from the channel to the destination.
     *
     * @param dst destination.
     * @return number of bytes transferred.
     *
     * @since 4.3
     */
    protected int readFromChannel(final ByteBuffer dst) throws IOException {
        final int bytesRead = this.channel.read(dst);
        if (bytesRead > 0) {
            this.metrics.incrementBytesTransferred(bytesRead);
        }
        return bytesRead;
    }

    /**
     * Reads from the channel to the session buffer.
     * @return number of bytes transferred.
     *
     * @since 4.3
     */
    protected int fillBufferFromChannel() throws IOException {
        final int bytesRead = this.buffer.fill(this.channel);
        if (bytesRead > 0) {
            this.metrics.incrementBytesTransferred(bytesRead);
        }
        return bytesRead;
    }

    /**
     * Reads from the channel to the destination.
     *
     * @param dst destination.
     * @param limit max number of bytes to transfer.
     * @return number of bytes transferred.
     *
     * @since 4.3
     */
    protected int readFromChannel(final ByteBuffer dst, final int limit) throws IOException {
        final int bytesRead;
        if (dst.remaining() > limit) {
            final int oldLimit = dst.limit();
            final int newLimit = oldLimit - (dst.remaining() - limit);
            dst.limit(newLimit);
            bytesRead = this.channel.read(dst);
            dst.limit(oldLimit);
        } else {
            bytesRead = this.channel.read(dst);
        }
        if (bytesRead > 0) {
            this.metrics.incrementBytesTransferred(bytesRead);
        }
        return bytesRead;
    }

}