com.adaptris.util.stream.StreamUtil.java Source code

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Here is the source code for com.adaptris.util.stream.StreamUtil.java

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/*
 * Copyright 2015 Adaptris Ltd.
 * 
 * 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.adaptris.util.stream;

import static org.apache.commons.lang.StringUtils.isEmpty;

import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Writer;
import java.nio.charset.Charset;

import org.apache.commons.io.IOUtils;

/**
 * Some utility methods associated with input streams.
 */
public abstract class StreamUtil {

    private static final int BUFSIZE = 1024 * 1024;

    /**
     * Read from the inputstream associated with the socket and write the data
     * straight out to a unique file in the temporary (system defined) directory
     *
     * @param input The inputstream to read from
     * @param expected the expected number of bytes
     * @return a File object corresponding to the temporary file that was created
     * @throws IOException if there was an error creating the file
     */
    public static File createFile(InputStream input, int expected) throws IOException {
        return createFile(input, expected, null);
    }

    /**
     * Read from the inputstream associated with the socket and write the data
     * straight out to a unique file in the specified directory
     *
     * @param input The inputstream to read from
     * @param expected the expected number of bytes
     * @param dir The directory in which to create the file
     * @return a File object corresponding to the temporary file that was created
     * @throws IOException if there was an creating the file
     */
    public static File createFile(InputStream input, int expected, String dir) throws IOException {

        File tempFile = null;
        if (isEmpty(dir)) {
            tempFile = File.createTempFile("tmp", "");
        } else {
            tempFile = File.createTempFile("tmp", "", new File(dir));
        }

        try (OutputStream out = new BufferedOutputStream(new FileOutputStream(tempFile))) {
            copyStream(input, out, expected);
        }
        return tempFile;
    }

    /**
     * Copy from an InputStream to an OutputStream for expected bytes.
     *
     * @param input the input stream to read from
     * @param output the output stream to write from
     * @param expected the number of bytes to copy
     * @throws IOException if there was an error.
     */
    public static void copyStream(InputStream input, OutputStream output, int expected) throws IOException {
        if (input == null || output == null) {
            return;
        }
        if (expected <= 0) {
            copyStream(input, output);
        } else {
            byte[] bytes = new byte[Math.min(expected, BUFSIZE)];

            int totalRead = 0;
            int bytesRead = 0;

            while (totalRead < expected) {
                bytesRead = input.read(bytes, 0, bytes.length);
                output.write(bytes, 0, bytesRead);
                totalRead = totalRead + bytesRead;
            }
            output.flush();
        }
    }

    /**
     * Copy from an InputStream to an OutputStream for expected bytes.
     *
     * @param input the input stream to read from
     * @param output the output stream to write from
     * @throws IOException if there was an IO error
     */
    public static void copyStream(InputStream input, OutputStream output) throws IOException {
        if (input == null || output == null) {
            return;
        }
        IOUtils.copy(input, output);
    }

    /**
     * Make a copy of an InputStream.
     * <p>
     * This method ensures that the resulting input stream can support a mark(),
     * and reset() call, by copying the contents of the input stream into a
     * ByteArrayInputStream
     *
     * @param input the InputStream to copy
     * @throws IOException if there was an error reading the stream.
     * @return a copy of the input stream
     */
    public static InputStream makeCopy(InputStream input) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        copyStream(input, out);
        return new ByteArrayInputStream(out.toByteArray());
    }

    public static void copyAndClose(InputStream input, Writer out) throws IOException {
        copyAndClose(input, out, Charset.defaultCharset());
    }

    public static void copyAndClose(InputStream input, Writer out, Charset charset) throws IOException {
        try (InputStream autoCloseIn = input; Writer autoCloseOut = out) {
            IOUtils.copy(autoCloseIn, autoCloseOut, charset);
        }
    }

    public static void copyAndClose(InputStream input, OutputStream out) throws IOException {
        try (InputStream autoCloseIn = input; OutputStream autoCloseOut = out) {
            IOUtils.copy(autoCloseIn, autoCloseOut);
        }
    }
}