com.liferay.blade.cli.util.Prompter.java Source code

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Here is the source code for com.liferay.blade.cli.util.Prompter.java

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/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * 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 com.liferay.blade.cli.util;

import java.io.InputStream;
import java.io.PrintStream;

import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Optional;
import java.util.Scanner;

import org.apache.commons.io.input.CloseShieldInputStream;

/**
 * @author Christopher Bryan Boyd
 */
public class Prompter {

    public static boolean confirm(String question) {
        return confirm(question, System.in, System.out, Optional.empty());
    }

    public static boolean confirm(String question, boolean defaultAnswer) {
        return confirm(question, System.in, System.out, Optional.of(defaultAnswer));
    }

    public static boolean confirm(String question, InputStream in, PrintStream out,
            Optional<Boolean> defaultAnswer) {
        String questionWithPrompt = _buildQuestionWithPrompt(question, defaultAnswer);

        Optional<Boolean> answer = _getBooleanAnswer(questionWithPrompt, in, out, defaultAnswer);

        if (answer.isPresent()) {
            return answer.get();
        } else {
            throw new NoSuchElementException("Unable to acquire an answer");
        }
    }

    private static String _buildQuestionWithPrompt(String question, Optional<Boolean> defaultAnswer) {
        String yesDefault = "y";
        String noDefault = "n";

        if (defaultAnswer.isPresent()) {
            if (defaultAnswer.get()) {
                yesDefault = "Y";
            } else {
                noDefault = "N";
            }
        }

        return question + " (" + yesDefault + "/" + noDefault + ")";
    }

    private static Optional<Boolean> _getBooleanAnswer(String questionWithPrompt, InputStream inputStream,
            PrintStream printStream, Optional<Boolean> defaultAnswer) {

        Optional<Boolean> answer = null;

        try (CloseShieldInputStream closeShieldInputStream = new CloseShieldInputStream(inputStream);
                Scanner scanner = new Scanner(closeShieldInputStream)) {

            while ((answer == null) || !answer.isPresent()) {
                printStream.println(questionWithPrompt);

                String readLine = null;

                while (((answer == null) || !answer.isPresent()) && !Objects.equals(answer, defaultAnswer)
                        && scanner.hasNextLine()) {

                    readLine = scanner.nextLine();

                    if (readLine != null) {
                        readLine = readLine.toLowerCase();

                        switch (readLine.trim()) {
                        case "y":
                        case "yes":
                            answer = Optional.of(true);

                            break;
                        case "n":
                        case "no":
                            answer = Optional.of(false);

                            break;
                        default:
                            if (defaultAnswer.isPresent()) {
                                answer = defaultAnswer;
                            } else {
                                printStream.println("Unrecognized input: " + readLine);

                                continue;
                            }

                            break;
                        }
                    } else {
                        answer = defaultAnswer;
                    }
                }
            }
        } catch (IllegalStateException ise) {
            throw new RuntimeException(ise);
        } catch (Exception exception) {
            if (defaultAnswer.isPresent()) {
                answer = defaultAnswer;
            }
        }

        return answer;
    }

}