Ant example source code file (ConcatResourceInputStream.java)

This example Ant source code file (ConcatResourceInputStream.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

concating, concatresourceinputstream, eof, eof, failed, inputstream, inputstream, io, ioexception, ioexception, iterator, projectcomponent, resource, resource, util

The ConcatResourceInputStream.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.InputStream;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.util.Iterator;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.ProjectComponent;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;

/**
 * Special <code>InputStream that will
 * concatenate the contents of Resources from a single ResourceCollection.
 * @since Ant 1.7
 */
public class ConcatResourceInputStream extends InputStream {

    private static final int EOF = -1;
    private boolean eof = false;
    private Iterator iter;
    private InputStream currentStream;
    private ProjectComponent managingPc;
    private boolean ignoreErrors = false;

  /**
   * Construct a new ConcatResourceInputStream
   * for the specified ResourceCollection.
   * @param rc the ResourceCollection to combine.
   */
    public ConcatResourceInputStream(ResourceCollection rc) {
        iter = rc.iterator();
    }

    /**
     * Set whether this ConcatResourceInputStream ignores errors.
     * @param b whether to ignore errors.
     */
    public void setIgnoreErrors(boolean b) {
        ignoreErrors = b;
    }

    /**
     * Find out whether this ConcatResourceInputStream ignores errors.
     * @return boolean ignore-errors flag.
     */
    public boolean isIgnoreErrors() {
        return ignoreErrors;
    }

    /**
     * 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 {
        if (eof) {
            return EOF;
        }
        int result = readCurrent();
        if (result == EOF) {
            nextResource();
            result = readCurrent();
        }
        return result;
    }

    /**
     * Set a managing <code>ProjectComponent for
     * this <code>ConcatResourceInputStream.
     * @param pc   the managing <code>ProjectComponent.
     */
    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 {
            (loglevel > Project.MSG_WARN ? System.out : System.err).println(message);
        }
    }

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

    private void nextResource() throws IOException {
        closeCurrent();
        while (iter.hasNext()) {
            Resource r = (Resource) iter.next();
            if (!r.isExists()) {
                continue;
            }
            log("Concating " + r.toLongString(), Project.MSG_VERBOSE);
            try {
                currentStream = new BufferedInputStream(r.getInputStream());
                return;
            } catch (IOException eyeOhEx) {
                if (!ignoreErrors) {
                    log("Failed to get input stream for " + r, Project.MSG_ERR);
                    throw eyeOhEx;
                }
            }
        }
        eof = true;
    }

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