| /* |
| * 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; |
| |
| import org.w3c.dom.Node; |
| |
| import org.apache.xpath.objects.XObject; |
| import org.apache.xpath.res.XPATHErrorResources; |
| import org.apache.xalan.res.XSLMessages; |
| |
| import org.xml.sax.XMLReader; |
| |
| import javax.xml.transform.TransformerConfigurationException; |
| import javax.xml.transform.TransformerException; |
| |
| import org.apache.xml.utils.SAXSourceLocator; |
| |
| import javax.xml.transform.SourceLocator; |
| import javax.xml.transform.ErrorListener; |
| |
| /** |
| * This abstract class serves as the base for all expression objects. An |
| * Expression can be executed to return a {@link org.apache.xpath.objects.XObject}, |
| * normally has a location within a document or DOM, can send error and warning |
| * events, and normally do not hold state and are meant to be immutable once |
| * construction has completed. An exception to the immutibility rule is iterators |
| * and walkers, which must be cloned in order to be used -- the original must |
| * still be immutable. |
| */ |
| public abstract class Expression implements java.io.Serializable |
| { |
| |
| /** |
| * The location where this expression was built from. Need for diagnostic |
| * messages. May be null. |
| * @serial |
| */ |
| protected SourceLocator m_slocator; |
| |
| /** |
| * Tell if this expression or it's subexpressions can traverse outside |
| * the current subtree. |
| * |
| * @return true if traversal outside the context node's subtree can occur. |
| */ |
| public boolean canTraverseOutsideSubtree() |
| { |
| return false; |
| } |
| |
| /** |
| * Set the location where this expression was built from. |
| * |
| * |
| * @param locator the location where this expression was built from, may be |
| * null. |
| */ |
| public void setSourceLocator(SourceLocator locator) |
| { |
| m_slocator = locator; |
| } |
| |
| /** |
| * Execute an expression in the XPath runtime context, and return the |
| * result of the expression. |
| * |
| * |
| * @param xctxt The XPath runtime context. |
| * |
| * @return The result of the expression in the form of a <code>XObject</code>. |
| * |
| * @throws javax.xml.transform.TransformerException if a runtime exception |
| * occurs. |
| */ |
| public abstract XObject execute(XPathContext xctxt) |
| throws javax.xml.transform.TransformerException; |
| |
| /** |
| * Warn the user of an problem. |
| * |
| * @param xctxt The XPath runtime context. |
| * @param msg An error number that corresponds to one of the numbers found |
| * in {@link org.apache.xpath.res.XPATHErrorResources}, which is |
| * a key for a format string. |
| * @param args An array of arguments represented in the format string, which |
| * may be null. |
| * |
| * @throws TransformerException if the current ErrorListoner determines to |
| * throw an exception. |
| */ |
| public void warn(XPathContext xctxt, int msg, Object[] args) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| java.lang.String fmsg = XSLMessages.createXPATHWarning(msg, args); |
| |
| if (null != xctxt) |
| { |
| ErrorListener eh = xctxt.getErrorListener(); |
| |
| // TO DO: Need to get stylesheet Locator from here. |
| eh.warning(new TransformerException(fmsg, xctxt.getSAXLocator())); |
| } |
| } |
| |
| /** |
| * Tell the user of an assertion error, and probably throw an |
| * exception. |
| * |
| * @param b If false, a runtime exception will be thrown. |
| * @param msg The assertion message, which should be informative. |
| * |
| * @throws RuntimeException if the b argument is false. |
| */ |
| public void assert(boolean b, java.lang.String msg) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| if (!b) |
| { |
| java.lang.String fMsg = XSLMessages.createXPATHMessage( |
| XPATHErrorResources.ER_INCORRECT_PROGRAMMER_ASSERTION, |
| new Object[]{ msg }); |
| |
| throw new RuntimeException(fMsg); |
| } |
| } |
| |
| /** |
| * Tell the user of an error, and probably throw an |
| * exception. |
| * |
| * @param xctxt The XPath runtime context. |
| * @param msg An error number that corresponds to one of the numbers found |
| * in {@link org.apache.xpath.res.XPATHErrorResources}, which is |
| * a key for a format string. |
| * @param args An array of arguments represented in the format string, which |
| * may be null. |
| * |
| * @throws TransformerException if the current ErrorListoner determines to |
| * throw an exception. |
| */ |
| public void error(XPathContext xctxt, int msg, Object[] args) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| java.lang.String fmsg = XSLMessages.createXPATHMessage(msg, args); |
| |
| if (null != xctxt) |
| { |
| ErrorListener eh = xctxt.getErrorListener(); |
| TransformerException te = new TransformerException(fmsg, m_slocator); |
| |
| eh.fatalError(te); |
| } |
| } |
| } |