javax.servlet.jsp.el.Expression Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
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*/
package javax.servlet.jsp.el;
/**
* The abstract class for a prepared expression.
*
* An instance of an Expression can be obtained via from an
* ExpressionEvaluator instance.
*
* An Expression may or not have done a syntactic parse of the expression.
* A client invoking the evaluate() method should be ready for the case
* where ELParseException exceptions are raised.
*
* @since 2.0
* @deprecated
*/
public abstract class Expression {
/**
* Evaluates an expression that was previously prepared. In some
* implementations preparing an expression involves full syntactic
* validation, but others may not do so. Evaluating the expression may
* raise an ELParseException as well as other ELExceptions due to
* run-time evaluation.
*
* @param vResolver A VariableResolver instance that can be used at
* runtime to resolve the name of implicit objects into Objects.
* @return The result of the expression evaluation.
*
* @exception ELException Thrown if the expression evaluation failed.
*/
public abstract Object evaluate( VariableResolver vResolver )
throws ELException;
}