[14982] | 1 | /*
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| 2 | * Copyright 2002-2005 The Apache Software Foundation
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| 3 | *
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License");
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| 5 | * you may not use this file except in compliance with the License.
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| 6 | * You may obtain a copy of the License at
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| 7 | *
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0
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| 9 | *
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| 10 | * Unless required by applicable law or agreed to in writing, software
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS,
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 13 | * See the License for the specific language governing permissions and
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| 14 | * limitations under the License.
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| 15 | *
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| 16 | */
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| 17 |
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| 18 | package org.apache.tools.ant.input;
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| 19 |
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| 20 | import java.io.DataInputStream;
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| 21 | import java.io.IOException;
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| 22 | import java.io.InputStream;
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| 23 | import java.util.Enumeration;
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| 24 | import org.apache.tools.ant.BuildException;
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| 25 | import org.apache.tools.ant.util.KeepAliveInputStream;
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| 26 |
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| 27 | /**
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| 28 | * Prompts on System.err, reads input from System.in
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| 29 | *
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| 30 | * @since Ant 1.5
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| 31 | */
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| 32 | public class DefaultInputHandler implements InputHandler {
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| 33 |
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| 34 | /**
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| 35 | * Empty no-arg constructor
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| 36 | */
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| 37 | public DefaultInputHandler() {
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| 38 | }
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| 39 |
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| 40 | /**
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| 41 | * Prompts and requests input. May loop until a valid input has
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| 42 | * been entered.
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| 43 | * @param request the request to handle
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| 44 | * @throws BuildException if not possible to read from console
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| 45 | */
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| 46 | public void handleInput(InputRequest request) throws BuildException {
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| 47 | String prompt = getPrompt(request);
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| 48 | DataInputStream in = null;
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| 49 | try {
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| 50 | in =
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| 51 | new DataInputStream(new KeepAliveInputStream(getInputStream()));
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| 52 | do {
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| 53 | System.err.println(prompt);
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| 54 | System.err.flush();
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| 55 | try {
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| 56 | String input = in.readLine();
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| 57 | request.setInput(input);
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| 58 | } catch (IOException e) {
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| 59 | throw new BuildException("Failed to read input from"
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| 60 | + " Console.", e);
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| 61 | }
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| 62 | } while (!request.isInputValid());
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| 63 | } finally {
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| 64 | if (in != null) {
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| 65 | try {
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| 66 | in.close();
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| 67 | } catch (IOException e) {
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| 68 | throw new BuildException("Failed to close input.", e);
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| 69 | }
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| 70 | }
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| 71 | }
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| 72 | }
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| 73 |
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| 74 | /**
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| 75 | * Constructs user prompt from a request.
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| 76 | *
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| 77 | * <p>This implementation adds (choice1,choice2,choice3,...) to the
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| 78 | * prompt for <code>MultipleChoiceInputRequest</code>s.</p>
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| 79 | *
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| 80 | * @param request the request to construct the prompt for.
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| 81 | * Must not be <code>null</code>.
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| 82 | * @return the prompt to ask the user
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| 83 | */
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| 84 | protected String getPrompt(InputRequest request) {
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| 85 | String prompt = request.getPrompt();
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| 86 | if (request instanceof MultipleChoiceInputRequest) {
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| 87 | StringBuffer sb = new StringBuffer(prompt);
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| 88 | sb.append("(");
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| 89 | Enumeration e =
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| 90 | ((MultipleChoiceInputRequest) request).getChoices().elements();
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| 91 | boolean first = true;
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| 92 | while (e.hasMoreElements()) {
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| 93 | if (!first) {
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| 94 | sb.append(",");
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| 95 | }
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| 96 | sb.append(e.nextElement());
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| 97 | first = false;
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| 98 | }
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| 99 | sb.append(")");
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| 100 | prompt = sb.toString();
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| 101 | }
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| 102 | return prompt;
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| 103 | }
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| 104 |
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| 105 | /**
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| 106 | * Returns the input stream from which the user input should be read.
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| 107 | * @return the input stream from which the user input should be read.
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| 108 | */
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| 109 | protected InputStream getInputStream() {
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| 110 | return System.in;
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| 111 | }
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| 112 |
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| 113 | }
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