com.huaweicloud.dis.core.util.IOUtils Maven / Gradle / Ivy

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/*
 * Copyright 2002-2010 the original author or authors.
 *
 * 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.huaweicloud.dis.core.util;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.huaweicloud.dis.core.internal.Releasable;

/**
 * Utilities for IO operations.
 */
public enum IOUtils {
    ;
    private static final int BUFFER_SIZE = 1024 * 4;
    private static final Log defaultLog = LogFactory.getLog(IOUtils.class);

	/**
	 * Reads and returns the rest of the given input stream as a byte array. Caller
	 * is responsible for closing the given input stream.
	 * 
	 * @param is
	 *            The given inputstream.
	 * @return The byte array output.
	 * @throws IOException
	 *             if there is any IO exception during read or write.
	 */
    public static byte[] toByteArray(InputStream is) throws IOException {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        try {
            byte[] b = new byte[BUFFER_SIZE];
            int n = 0;
            while ((n = is.read(b)) != -1) {
                output.write(b, 0, n);
            }
            return output.toByteArray();
        } finally {
            output.close();
        }
    }

    /**
     * Reads and returns the rest of the given input stream as a string.
     * Caller is responsible for closing the given input stream.
     * 
     * @param is
	 *            The given inputstream.
	 * @return The byte array output.
	 * @throws IOException
	 *             if there is any IO exception during read or write.
     */
    public static String toString(InputStream is) throws IOException {
        return new String(toByteArray(is), StringUtils.UTF8);
    }

    /**
     * Closes the given Closeable quietly.
     *
     * @param is  the given closeable
     * @param log logger used to log any failure should the close fail
     */
    public static void closeQuietly(Closeable is, Log log) {
        if (is != null) {
            try {
                is.close();
            } catch (IOException ex) {
                Log logger = log == null ? defaultLog : log;
                if (logger.isDebugEnabled())
                    logger.debug("Ignore failure in closing the Closeable", ex);
            }
        }
    }

    /**
     * Releases the given {@link java.io.Closeable} especially if it was an instance of
     * {@link com.huaweicloud.dis.core.internal.Releasable}.
     * 
     * @param is  the given closeable
     * @param log logger used to log any failure should the close fail
     */
    public static void release(Closeable is, Log log) {
        closeQuietly(is, log);
        if (is instanceof Releasable) {
            Releasable r = (Releasable) is;
            r.release();
        }
    }

	/**
	 * Copies all bytes from the given input stream to the given output stream.
	 * Caller is responsible for closing the streams.
	 *
	 * @param in
	 *            The input stream to read.
	 * @param out
	 *            The output stream to write.
	 * @return The output stream.
	 * @throws java.io.IOException
	 *             if there is any IO exception during read or write.
	 */
    public static long copy(InputStream in, OutputStream out)
            throws IOException {
        byte[] buf = new byte[BUFFER_SIZE];
        long count = 0;
        int n = 0;
        while ((n = in.read(buf)) > -1) {
            out.write(buf, 0, n);
            count += n;
        }
        return count;
    }
}