/*
* Copyright 2015 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
*
* 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.springframework.statemachine.support;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.statemachine.StateContext;
import org.springframework.util.Assert;
/**
* Helper class to work with a spel expressions and {@link StateContext}.
*
* @author Janne Valkealahti
*
*/
public class StateContextExpressionMethods {
private final StandardEvaluationContext context;
/**
* Instantiates a new state context expression methods
* with a {@link StandardEvaluationContext}.
*
* @param evaluationContext the spel evaluation context
*/
public StateContextExpressionMethods(StandardEvaluationContext evaluationContext) {
this.context = evaluationContext;
}
/**
* Gets the value.
*
* @param <T> the generic type
* @param expression the expression
* @param stateContext the state context
* @param desiredResultType the desired result type
* @return the value
* @throws EvaluationException the evaluation exception
*/
public <T> T getValue(Expression expression, StateContext<?, ?> stateContext, Class<T> desiredResultType)
throws EvaluationException {
Assert.notNull(expression, "Expression cannot be null");
return expression.getValue(context, stateContext, desiredResultType);
}
}