/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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
 *
 *      https://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,
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 * See the License for the specific language governing permissions and
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package org.springframework.expression;

import org.springframework.lang.Nullable;

By default the mathematical operators Operation support simple types like numbers. By providing an implementation of OperatorOverloader, a user of the expression language can support these operations on other types.
Author:Andy Clement
Since:3.0
/** * By default the mathematical operators {@link Operation} support simple types * like numbers. By providing an implementation of OperatorOverloader, a user * of the expression language can support these operations on other types. * * @author Andy Clement * @since 3.0 */
public interface OperatorOverloader {
Return true if the operator overloader supports the specified operation between the two operands and so should be invoked to handle it.
Params:
  • operation – the operation to be performed
  • leftOperand – the left operand
  • rightOperand – the right operand
Throws:
Returns:true if the OperatorOverloader supports the specified operation between the two operands
/** * Return true if the operator overloader supports the specified operation * between the two operands and so should be invoked to handle it. * @param operation the operation to be performed * @param leftOperand the left operand * @param rightOperand the right operand * @return true if the OperatorOverloader supports the specified operation * between the two operands * @throws EvaluationException if there is a problem performing the operation */
boolean overridesOperation(Operation operation, @Nullable Object leftOperand, @Nullable Object rightOperand) throws EvaluationException;
Execute the specified operation on two operands, returning a result. See Operation for supported operations.
Params:
  • operation – the operation to be performed
  • leftOperand – the left operand
  • rightOperand – the right operand
Throws:
Returns:the result of performing the operation on the two operands
/** * Execute the specified operation on two operands, returning a result. * See {@link Operation} for supported operations. * @param operation the operation to be performed * @param leftOperand the left operand * @param rightOperand the right operand * @return the result of performing the operation on the two operands * @throws EvaluationException if there is a problem performing the operation */
Object operate(Operation operation, @Nullable Object leftOperand, @Nullable Object rightOperand) throws EvaluationException; }