| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 1999 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 acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" 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", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * 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 |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * 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 and was |
| * originally based on software copyright (c) 1999, Lotus |
| * Development Corporation., http://www.lotus.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xpath.functions; |
| |
| //import org.w3c.dom.Node; |
| |
| import javax.xml.transform.TransformerException; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.ExpressionOwner; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.XPathVisitor; |
| import org.apache.xpath.objects.XObject; |
| |
| /** |
| * <meta name="usage" content="advanced"/> |
| * This is a superclass of all XPath functions. This allows two |
| * ways for the class to be called. One method is that the |
| * super class processes the arguments and hands the results to |
| * the derived class, the other method is that the derived |
| * class may process it's own arguments, which is faster since |
| * the arguments don't have to be added to an array, but causes |
| * a larger code footprint. |
| */ |
| public abstract class Function extends Expression |
| { |
| |
| /** |
| * Set an argument expression for a function. This method is called by the |
| * XPath compiler. |
| * |
| * @param arg non-null expression that represents the argument. |
| * @param argNum The argument number index. |
| * |
| * @throws WrongNumberArgsException If the argNum parameter is beyond what |
| * is specified for this function. |
| */ |
| public void setArg(Expression arg, int argNum) |
| throws WrongNumberArgsException |
| { |
| throw new WrongNumberArgsException("0"); |
| } |
| |
| /** |
| * Check that the number of arguments passed to this function is correct. |
| * This method is meant to be overloaded by derived classes, to check for |
| * the number of arguments for a specific function type. This method is |
| * called by the compiler for static number of arguments checking. |
| * |
| * @param argNum The number of arguments that is being passed to the function. |
| * |
| * @throws WrongNumberArgsException |
| */ |
| public void checkNumberArgs(int argNum) throws WrongNumberArgsException |
| { |
| if (argNum != 0) |
| throw new WrongNumberArgsException("0"); |
| } |
| |
| /** |
| * Execute an XPath function object. The function must return |
| * a valid object. |
| * @param xctxt The execution current context. |
| * @return A valid XObject. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException |
| { |
| |
| // Programmer's assert. (And, no, I don't want the method to be abstract). |
| System.out.println("Error! Function.execute should not be called!"); |
| |
| return null; |
| } |
| |
| /** |
| * Call the visitors for the function arguments. |
| */ |
| public void callArgVisitors(XPathVisitor visitor) |
| { |
| } |
| |
| |
| /** |
| * @see XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor) |
| */ |
| public void callVisitors(ExpressionOwner owner, XPathVisitor visitor) |
| { |
| if(visitor.visitFunction(owner, this)) |
| { |
| callArgVisitors(visitor); |
| } |
| } |
| |
| /** |
| * @see Expression#deepEquals(Expression) |
| */ |
| public boolean deepEquals(Expression expr) |
| { |
| if(!isSameClass(expr)) |
| return false; |
| |
| return true; |
| } |
| |
| |
| } |