/*
* Copyright 2002-2004 The Apache Software Foundation
*
* 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 org.apache.tools.ant.input;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.util.KeepAliveInputStream;
/**
* Prompts on System.err, reads input from System.in
*
* @author Stefan Bodewig
* @version $Revision: 1.12.2.4 $
* @since Ant 1.5
*/
public class DefaultInputHandler implements InputHandler {
/**
* Empty no-arg constructor
*/
public DefaultInputHandler() {
}
/**
* Prompts and requests input. May loop until a valid input has
* been entered.
* @param request the request to handle
* @throws BuildException if not possible to read from console
*/
public void handleInput(InputRequest request) throws BuildException {
String prompt = getPrompt(request);
DataInputStream in = null;
try {
in =
new DataInputStream(new KeepAliveInputStream(getInputStream()));
do {
System.err.println(prompt);
System.err.flush();
try {
String input = in.readLine();
request.setInput(input);
} catch (IOException e) {
throw new BuildException("Failed to read input from"
+ " Console.", e);
}
} while (!request.isInputValid());
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
throw new BuildException("Failed to close input.", e);
}
}
}
}
/**
* Constructs user prompt from a request.
*
* <p>This implementation adds (choice1,choice2,choice3,...) to the
* prompt for <code>MultipleChoiceInputRequest</code>s.</p>
*
* @param request the request to construct the prompt for.
* Must not be <code>null</code>.
* @return the prompt to ask the user
*/
protected String getPrompt(InputRequest request) {
String prompt = request.getPrompt();
if (request instanceof MultipleChoiceInputRequest) {
StringBuffer sb = new StringBuffer(prompt);
sb.append("(");
Enumeration e =
((MultipleChoiceInputRequest) request).getChoices().elements();
boolean first = true;
while (e.hasMoreElements()) {
if (!first) {
sb.append(",");
}
sb.append(e.nextElement());
first = false;
}
sb.append(")");
prompt = sb.toString();
}
return prompt;
}
/**
* Returns the input stream from which the user input should be read.
* @return the input stream from which the user input should be read.
*/
protected InputStream getInputStream() {
return System.in;
}
}