/* * Copyright 2002-2005 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 * * @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. * *
This implementation adds (choice1,choice2,choice3,...) to the
* prompt for MultipleChoiceInputRequest
s.
null
.
* @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;
}
}