Ant example source code file (GreedyInputHandler.java)

This example Ant source code file (GreedyInputHandler.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

buffer_size, buildexception, buildexception, bytearrayoutputstream, bytearrayoutputstream, defaultinputhandler, greedyinputhandler, inputstream, interruptedexception, interruptedexception, io, streampumper, string, thread, thread

The GreedyInputHandler.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.input;

import java.io.InputStream;
import java.io.ByteArrayOutputStream;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.taskdefs.StreamPumper;
import org.apache.tools.ant.util.FileUtils;

/**
 * Prompts on System.err, reads input from System.in until EOF
 *
 * @since Ant 1.7
 */
public class GreedyInputHandler extends DefaultInputHandler {

    private static final int BUFFER_SIZE = 1024;

    /**
     * Empty no-arg constructor
     */
    public GreedyInputHandler() {
    }

    /**
     * Prompts and requests input.
     * @param request the request to handle
     * @throws BuildException if not possible to read from console,
     *         or if input is invalid.
     */
    public void handleInput(InputRequest request) throws BuildException {
        String prompt = getPrompt(request);
        InputStream in = null;
        try {
            in = getInputStream();
            System.err.println(prompt);
            System.err.flush();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            StreamPumper p = new StreamPumper(in, baos);
            Thread t = new Thread(p);
            t.start();
            try {
                t.join();
            } catch (InterruptedException e) {
                try {
                    t.join();
                } catch (InterruptedException e2) {
                    // Ignore
                }
            }
            request.setInput(new String(baos.toByteArray()));
            if (!(request.isInputValid())) {
                throw new BuildException(
                    "Received invalid console input");
            }
            if (p.getException() != null) {
                throw new BuildException(
                    "Failed to read input from console", p.getException());
            }
        } finally {
            FileUtils.close(in);
        }
    }
}