/*
* $Id: ELMatchSupport.java 471754 2006-11-06 14:55:09Z husted $
*
* 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, 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.apache.strutsel.taglib.logic;
import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
/**
* This class is used as a helper class for both the <code>org.apache.strutsel.taglib.logic.ELMatchTag</code>
* and <code>org.apache.strutsel.taglib.logic.ELNotMatchTag</code> classes.
* It's <code>condition</code> method encapsulates the common logic needed to
* examine the <code>location</code> attribute to determine how to do the
* comparison.
*/
class ELMatchSupport {
/**
* Performs a comparison of an expression and a value, with an optional
* location specifier in the expression (start or end).
*
* @param desired Indication of whether the "truth" value of the
* comparison is whether the expression and value are
* equal, or not equal.
* @param expr Expression to test against a value.
* @param value Value to test against an expression.
* @param location if set, is "start" or "end" to indicate to look at
* the start or end of the expression for the value.
* If null, look anywhere in the expression.
* @param messages <code>MessageResources</code> object to reference
* for error message text.
* @param pageContext used to save exception information, if needed.
* @return true if comparison result equals desired value, false
* otherwise.
*/
public static boolean condition(boolean desired, String expr, String value,
String location, MessageResources messages, PageContext pageContext)
throws JspException {
boolean result = false;
if (expr != null) {
// Perform the comparison requested by the location attribute
boolean matched = false;
if (location == null) {
matched = (expr.indexOf(value) >= 0);
} else if (location.equals("start")) {
matched = expr.startsWith(value);
} else if (location.equals("end")) {
matched = expr.endsWith(value);
} else {
JspException e =
new JspException(messages.getMessage("logic.location",
location));
TagUtils.getInstance().saveException(pageContext, e);
throw e;
}
result = (matched == desired);
}
return (result);
}
}