/*
* $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/expression/jexl/JexlExpressionFactory.java,v 1.9 2002/08/12 10:28:51 jstrachan Exp $
* $Revision: 1.9 $
* $Date: 2002/08/12 10:28:51 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2002 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
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*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* $Id: JexlExpressionFactory.java,v 1.9 2002/08/12 10:28:51 jstrachan Exp $
*/
package org.apache.commons.jelly.expression.jexl;
import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.expression.Expression;
import org.apache.commons.jelly.expression.ExpressionSupport;
import org.apache.commons.jelly.expression.ExpressionFactory;
//import org.apache.commons.jexl.resolver.FlatResolver;
/**
* Represents a factory of <a href="http://jakarta.apache.org/commons/jexl.html">Jexl</a>
* expression which fully supports the Expression Language in JSTL and JSP.
* In addition this ExpressionFactory can also support Ant style variable
* names, where '.' is used inside variable names.
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @version $Revision: 1.9 $
*/
public class JexlExpressionFactory implements ExpressionFactory {
/** whether we should allow Ant-style expresssions, using dots as part of variable name */
private boolean supportAntVariables = true;
// ExpressionFactory interface
//-------------------------------------------------------------------------
public Expression createExpression(final String text) throws Exception {
/*
org.apache.commons.jexl.Expression expr =
org.apache.commons.jexl.ExpressionFactory.createExpression(text);
if ( isSupportAntVariables() ) {
expr.addPostResolver(new FlatResolver());
}
return new JexlExpression( expr );
*/
final Expression jexlExpression = new JexlExpression(
org.apache.commons.jexl.ExpressionFactory.createExpression(text)
);
if ( isSupportAntVariables() && isValidAntVariableName(text) ) {
ExpressionSupport expr = new ExpressionSupport() {
public Object evaluate(JellyContext context) {
Object answer = jexlExpression.evaluate(context);
if ( answer == null ) {
answer = context.getVariable(text);
}
return answer;
}
};
return expr;
}
return jexlExpression;
}
// Properties
//-------------------------------------------------------------------------
/**
* @return whether we should allow Ant-style expresssions, using dots as
* part of variable name
*/
public boolean isSupportAntVariables() {
return supportAntVariables;
}
/**
* Sets whether we should allow Ant-style expresssions, using dots as
* part of variable name
*/
public void setSupportAntVariables(boolean supportAntVariables) {
this.supportAntVariables = supportAntVariables;
}
// Implementation methods
//-------------------------------------------------------------------------
/**
* @return true if the given string is a valid Ant variable name,
* typically thats alphanumeric text with '.' etc.
*/
protected boolean isValidAntVariableName(String text) {
char[] chars = text.toCharArray();
for (int i = 0, size = chars.length; i < size; i++ ) {
char ch = chars[i];
// could maybe be a bit more restrictive...
if ( Character.isWhitespace(ch) || ch == '[' ) {
return false;
}
}
return true;
}
}