001/*
002 * Copyright 2012-2016 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.boot.cli.command.shell;
018
019import java.util.Stack;
020
021/**
022 * Abstraction to manage a stack of prompts.
023 *
024 * @author Phillip Webb
025 */
026public class ShellPrompts {
027
028        private static final String DEFAULT_PROMPT = "$ ";
029
030        private final Stack<String> prompts = new Stack<String>();
031
032        /**
033         * Push a new prompt to be used by the shell.
034         * @param prompt the prompt
035         * @see #popPrompt()
036         */
037        public void pushPrompt(String prompt) {
038                this.prompts.push(prompt);
039        }
040
041        /**
042         * Pop a previously pushed prompt, returning to the previous value.
043         * @see #pushPrompt(String)
044         */
045        public void popPrompt() {
046                if (!this.prompts.isEmpty()) {
047                        this.prompts.pop();
048                }
049        }
050
051        /**
052         * Returns the current prompt.
053         * @return the current prompt
054         */
055        public String getPrompt() {
056                return this.prompts.isEmpty() ? DEFAULT_PROMPT : this.prompts.peek();
057        }
058
059}