com.ibm.stocator.fs.swift.SwiftInputStreamWrapper.java Source code

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Here is the source code for com.ibm.stocator.fs.swift.SwiftInputStreamWrapper.java

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/**
 * (C) Copyright IBM Corp. 2015, 2016
 *
 * 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 com.ibm.stocator.fs.swift;

import java.io.ByteArrayInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.httpclient.HttpMethod;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.ibm.stocator.fs.common.exception.ConnectionClosedException;

/**
 * Wraps the SwiftInputStream
 */
public class SwiftInputStreamWrapper extends InputStream {

    /*
     * Logger
     */
    private static final Logger LOG = LoggerFactory.getLogger(SwiftInputStreamWrapper.class);
    /*
     * HTTP method
     */
    private HttpMethod method;
    /*
     * Identify closed stream
     */
    private volatile boolean closed;
    /*
     * No more data to read
     */
    private volatile boolean finishReading;
    /*
     * Input stream
     */
    private InputStream inStream;

    /**
     * Constructor
     *
     * @param methodT HTTP method
     * @throws IOException if something went wrong
     */
    public SwiftInputStreamWrapper(HttpMethod methodT) throws IOException {
        method = methodT;
        try {
            inStream = method.getResponseBodyAsStream();
        } catch (IOException e) {
            inStream = new ByteArrayInputStream(new byte[] {});
            LOG.error(e.getMessage());
            throw closeAndThrow(e);
        }
    }

    @Override
    public void close() throws IOException {
        innerClose();
    }

    /**
     * Inner close method
     *
     * @return true if closed successfully
     * @throws IOException if close failed
     */
    private synchronized boolean innerClose() throws IOException {
        if (!closed) {
            try {
                if (method != null) {
                    if (!finishReading) {
                        method.abort();
                    }
                    method.releaseConnection();
                }
                if (inStream != null) {
                    inStream.close();
                }
                return true;
            } finally {
                closed = true;
                finishReading = true;
            }
        } else {
            return false;
        }
    }

    /**
     * Close connection and throw an exception
     *
     * @param ex the exception
     * @return new exception
     */
    private IOException closeAndThrow(IOException ex) {
        try {
            innerClose();
        } catch (IOException ioe) {
            LOG.error(ioe.getMessage());
            if (ex == null) {
                ex = ioe;
            }
        }
        return ex;
    }

    /**
     * Check if connection is closed or input stream is null
     *
     * @throws ConnectionClosedException if connection is closed
     */
    private synchronized void verifyClosed() throws ConnectionClosedException {
        if (closed || inStream == null) {
            throw new ConnectionClosedException("Connection is closed");
        }
    }

    @Override
    public int available() throws IOException {
        verifyClosed();
        try {
            return inStream.available();
        } catch (IOException e) {
            LOG.error(e.getMessage());
            throw closeAndThrow(e);
        }
    }

    @Override
    public int read() throws IOException {
        verifyClosed();
        int read = 0;
        try {
            read = inStream.read();
        } catch (EOFException e) {
            LOG.error(e.getMessage());
            read = -1;
        } catch (IOException e) {
            LOG.error(e.getMessage());
            throw closeAndThrow(e);
        }
        if (read < 0) {
            finishReading = true;
            LOG.debug("No more left to read");
            innerClose();
        }
        return read;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        verifyClosed();
        int read;
        try {
            read = inStream.read(b, off, len);
        } catch (EOFException e) {
            LOG.error(e.getMessage());
            read = -1;
        } catch (IOException e) {
            LOG.error(e.getMessage());
            throw closeAndThrow(e);
        }
        if (read < 0) {
            finishReading = true;
            LOG.debug("No more data to read");
            innerClose();
        }
        return read;
    }

}