org.springframework.binding.expression.Expression Maven / Gradle / Ivy
/*
* Copyright 2004-2012 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.binding.expression;
/**
* An expression capable of evaluating itself against context objects. Encapsulates the details of a previously parsed
* expression string. Provides a common abstraction for expression evaluation independent of any language like
* Spring EL or the Unified EL.
*
* @author Keith Donald
*/
public interface Expression {
/**
* Evaluate this expression in the provided context and return the result of evaluation.
* @param context the context to evaluate this expression in
* @return the evaluation result
* @throws EvaluationException an exception occurred during expression evaluation
*/
Object getValue(Object context) throws EvaluationException;
/**
* Set this expression in the provided context to the value provided.
* @param context the context on which the new value should be set
* @param value the new value to set
* @throws EvaluationException an exception occurred during expression evaluation
*/
void setValue(Object context, Object value) throws EvaluationException;
/**
* Returns the most general type that can be passed to the {@link #setValue(Object, Object)} method for the given
* context.
* @param context the context to evaluate
* @return the most general type of value that can be set on this context, or null if the type
* information cannot be determined
* @throws EvaluationException an exception occurred during expression evaluation
*/
Class getValueType(Object context) throws EvaluationException;
/**
* Returns the original string used to create this expression, unmodified.
* @return the original expression string
*/
String getExpressionString();
}