| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.metron.stellar.common.evaluators; |
| |
| import org.apache.metron.stellar.dsl.Token; |
| import org.apache.metron.stellar.common.generated.StellarParser; |
| |
| /** |
| * This is used to determine what is needed to evaluate a Stellar comparison expression. A Stellar comparison |
| * expression is an expression that uses operators such as {@literal '<', '<=', '>', '>=', '==', '!=' } to compare |
| * values in Stellar. There are two main types of comparisons in Stellar, |
| * {@literal equality ('==', '!=') and comparison ('<', '<=', '>', '>='). } |
| */ |
| public interface ComparisonExpressionEvaluator { |
| |
| /** |
| * This will compare the values of {@code left} and {@code right} using the {@code op} input to determine a value |
| * to return. |
| * @param left The token representing the left side of a comparison expression. |
| * @param right The token representing the right side of a comparison expression. |
| * @param op This is a representation of a comparison operator {@literal (eg. <, <=, >, >=, ==, !=) } |
| * @return True if the expression is evaluated to be true, otherwise false. An example of expressions that |
| * should be true are {@code 1 == 1}, {@code 1f > 0}, etc. |
| */ |
| boolean evaluate(Token<?> left, Token<?> right, StellarParser.ComparisonOpContext op); |
| } |
