org.jaxen.expr.Expr Maven / Gradle / Ivy
/*
* $Header$
* $Revision$
* $Date$
*
* ====================================================================
*
* Copyright 2000-2002 bob mcwhirter & James Strachan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the Jaxen Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ====================================================================
* This software consists of voluntary contributions made by many
* individuals on behalf of the Jaxen Project and was originally
* created by bob mcwhirter and
* James Strachan . For more information on the
* Jaxen Project, please see .
*
* $Id$
*/
package org.jaxen.expr;
import java.io.Serializable;
import org.jaxen.Context;
import org.jaxen.JaxenException;
/**
* Represents an XPath expression. This is production 14 in the
* XPath 1.0 specification:
*
* [14] Expr ::= OrExpr
*
*/
public interface Expr extends Serializable
{
/**
* Returns a String containing the XPath expression.
*
* @return the text form of this XPath expression
*/
String getText();
/**
* Simplifies the XPath expression. For example, the expression
* //para[1 = 1]
could be simplified to
* //para
. In practice, this is usually a noop.
* Jaxen does not currently perform any simplification.
*
* @return the simplified expression
*/
Expr simplify();
/**
* Evaluate the expression in the given context, and return the result.
* The result will be a java.lang.Double
for expressions that
* return a number, a java.lang.String
for expressions that
* return a string, a java.lang.Boolean
for expressions that
* return a boolean, and a java.util.List
for expressions that
* return a node-set. In the latter case, the elements of the list are
* the actual objects from the source document model. Copies are not made.
*
* @param context the context in which the expression is evaluated
* @return an object representing the result of the evaluation
* @throws JaxenException
*/
Object evaluate(Context context) throws JaxenException;
}