javax.servlet.jsp.el.Expression Maven / Gradle / Ivy
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* Copyright (c) 1997, 2018 Oracle and/or its affiliates and others.
* All rights reserved.
* Copyright 2004 The Apache Software Foundation
*
* 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 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.
*
*
* @deprecated As of JSP 2.1, replaced by {@link javax.el.ValueExpression}
* @since JSP 2.0
*/
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;
}