Ant example source code file (ConcatFileInputStream.java)

This example Ant source code file (ConcatFileInputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

bufferedinputstream, concatfileinputstream, concatfileinputstream, eof, eof, failed, file, fileinputstream, inputstream, inputstream, io, ioexception, ioexception, opening, projectcomponent

The ConcatFileInputStream.java source code

/*
 *  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.
 *
 */

package org.apache.tools.ant.util;

import java.io.File;
import java.io.InputStream;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.FileInputStream;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.ProjectComponent;
import org.apache.tools.ant.Task;

/**
 * Special <code>InputStream that will
 * concatenate the contents of an array of files.
 */
public class ConcatFileInputStream extends InputStream {

    private static final int EOF = -1;
    private int currentIndex = -1;
    private boolean eof = false;
    private File[] file;
    private InputStream currentStream;
    private ProjectComponent managingPc;

  /**
   * Construct a new <code>ConcatFileInputStream
   * with the specified <code>File[].
   * @param file   <code>File[].
   * @throws IOException if I/O errors occur.
   */
    public ConcatFileInputStream(File[] file) throws IOException {
        this.file = file;
    }

    /**
     * Close the stream.
     * @throws IOException if there is an error.
     */
    public void close() throws IOException {
        closeCurrent();
        eof = true;
    }

    /**
     * Read a byte.
     * @return the byte (0 - 255) or -1 if this is the end of the stream.
     * @throws IOException if there is an error.
     */
    public int read() throws IOException {
        int result = readCurrent();
        if (result == EOF && !eof) {
            openFile(++currentIndex);
            result = readCurrent();
        }
        return result;
    }

    /**
     * Set a managing <code>Task for
     * this <code>ConcatFileInputStream.
     * @param task   the managing <code>Task.
     */
    public void setManagingTask(Task task) {
        setManagingComponent(task);
    }

    /**
     * Set a managing <code>Task for
     * this <code>ConcatFileInputStream.
     * @param pc the managing <code>Task.
     */
    public void setManagingComponent(ProjectComponent pc) {
        this.managingPc = pc;
    }

    /**
     * Log a message with the specified logging level.
     * @param message    the <code>String message.
     * @param loglevel   the <code>int logging level.
     */
    public void log(String message, int loglevel) {
        if (managingPc != null) {
            managingPc.log(message, loglevel);
        } else {
            if (loglevel > Project.MSG_WARN) {
                System.out.println(message);
            } else {
                System.err.println(message);
            }
        }
    }

    private int readCurrent() throws IOException {
        return (eof || currentStream == null) ? EOF : currentStream.read();
    }

    private void openFile(int index) throws IOException {
        closeCurrent();
        if (file != null && index < file.length) {
            log("Opening " + file[index], Project.MSG_VERBOSE);
            try {
                currentStream = new BufferedInputStream(
                    new FileInputStream(file[index]));
            } catch (IOException eyeOhEx) {
                log("Failed to open " + file[index], Project.MSG_ERR);
                throw eyeOhEx;
            }
        } else {
            eof = true;
        }
    }

    private void closeCurrent() {
        FileUtils.close(currentStream);
        currentStream = null;
    }
}