org.apache.xpath.functions.FuncSubstring Maven / Gradle / Ivy
/*
* 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.
*/
/*
* $Id: FuncSubstring.java 468655 2006-10-28 07:12:06Z minchau $
*/
package org.apache.xpath.functions;
import org.apache.xalan.res.XSLMessages;
import org.apache.xml.utils.XMLString;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.objects.XString;
import org.apache.xpath.res.XPATHErrorResources;
/**
* Execute the Substring() function.
* @xsl.usage advanced
*/
public class FuncSubstring extends Function3Args
{
static final long serialVersionUID = -5996676095024715502L;
/**
* Execute the function. The function must return
* a valid object.
* @param xctxt The current execution context.
* @return A valid XObject.
*
* @throws javax.xml.transform.TransformerException
*/
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{
XMLString s1 = m_arg0.execute(xctxt).xstr();
double start = m_arg1.execute(xctxt).num();
int lenOfS1 = s1.length();
XMLString substr;
if (lenOfS1 <= 0)
return XString.EMPTYSTRING;
else
{
int startIndex;
if (Double.isNaN(start))
{
// Double.MIN_VALUE doesn't work with math below
// so just use a big number and hope I never get caught.
start = -1000000;
startIndex = 0;
}
else
{
start = Math.round(start);
startIndex = (start > 0) ? (int) start - 1 : 0;
}
if (null != m_arg2)
{
double len = m_arg2.num(xctxt);
int end = (int) (Math.round(len) + start) - 1;
// Normalize end index.
if (end < 0)
end = 0;
else if (end > lenOfS1)
end = lenOfS1;
if (startIndex > lenOfS1)
startIndex = lenOfS1;
substr = s1.substring(startIndex, end);
}
else
{
if (startIndex > lenOfS1)
startIndex = lenOfS1;
substr = s1.substring(startIndex);
}
}
return (XString)substr; // cast semi-safe
}
/**
* Check that the number of arguments passed to this function is correct.
*
*
* @param argNum The number of arguments that is being passed to the function.
*
* @throws WrongNumberArgsException
*/
public void checkNumberArgs(int argNum) throws WrongNumberArgsException
{
if (argNum < 2)
reportWrongNumberArgs();
}
/**
* Constructs and throws a WrongNumberArgException with the appropriate
* message for this function object.
*
* @throws WrongNumberArgsException
*/
protected void reportWrongNumberArgs() throws WrongNumberArgsException {
throw new WrongNumberArgsException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_TWO_OR_THREE, null)); //"2 or 3");
}
}