1 /* 2 * Copyright (C) 2018 Google, Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.google.escapevelocity; 17 18 /** 19 * A node in the parse tree representing a constant value. Evaluating the node yields the constant 20 * value. Instances of this class are used both in expressions, like the {@code 23} in 21 * {@code #set ($x = 23)}, and for literal text in templates. In the template... 22 * <pre>{@code 23 * abc#{if}($x == 5)def#{end}xyz 24 * }</pre> 25 * ...each of the strings {@code abc}, {@code def}, {@code xyz} is represented by an instance of 26 * this class that {@linkplain #evaluate evaluates} to that string, and the value {@code 5} is 27 * represented by an instance of this class that evaluates to the integer 5. 28 * 29 * @author emcmanus@google.com (Éamonn McManus) 30 */ 31 class ConstantExpressionNode extends ExpressionNode { 32 private final Object value; 33 ConstantExpressionNode(String resourceName, int lineNumber, Object value)34 ConstantExpressionNode(String resourceName, int lineNumber, Object value) { 35 super(resourceName, lineNumber); 36 this.value = value; 37 } 38 39 @Override evaluate(EvaluationContext context)40 Object evaluate(EvaluationContext context) { 41 return value; 42 } 43 } 44