pt.lunacloud.services.storage.model.StorageObjectInputStream.java Source code

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Here is the source code for pt.lunacloud.services.storage.model.StorageObjectInputStream.java

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/*
 * Copyright 2012-2013 Amazon Technologies, Inc.
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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 pt.lunacloud.services.storage.model;

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

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.conn.EofSensorInputStream;

/**
 * Input stream representing the content of an {@link StorageObject}. In
 * addition to the methods supplied by the {@link InputStream} class,
 * {@link StorageObjectInputStream} supplies the abort() method, which will
 * terminate an HTTP connection to the Storage object.
 */
public class StorageObjectInputStream extends FilterInputStream {

    private final HttpRequestBase httpRequest;

    public StorageObjectInputStream(InputStream in, HttpRequestBase httpRequest) {
        super(in);
        this.httpRequest = httpRequest;
    }

    /**
     * Aborts the underlying http request without reading any more data and
     * closes the stream.
     * <p>
     * By default Apache {@link HttpClient} tries to reuse http connections by
     * reading to the end of an attached input stream on
     * {@link InputStream#close()}. This is efficient from a socket pool
     * management perspective, but for objects with large payloads can incur
     * significant overhead while bytes are read from Storage and discarded.
     * It's up to clients to decide when to take the performance hit implicit in
     * not reusing an http connection in order to not read unnecessary
     * information from Storage.
     * 
     * @see EofSensorInputStream
     */
    public void abort() throws IOException {
        getHttpRequest().abort();
        try {
            close();
        } catch (SocketException e) {
            // expected from some implementations because the stream is closed
        }
    }

    /**
     * Returns the http request from which this input stream is derived.
     */
    public HttpRequestBase getHttpRequest() {
        return httpRequest;
    }

}