| /* |
| * 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.operations; |
| |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.XPath; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.objects.XObject; |
| |
| import org.w3c.dom.Node; |
| |
| /** |
| * The baseclass for a binary operation. |
| */ |
| public class Operation extends Expression |
| { |
| |
| /** The left operand expression. |
| * @serial */ |
| protected Expression m_left; |
| |
| /** The right operand expression. |
| * @serial */ |
| protected Expression m_right; |
| |
| /** |
| * This function is used to fixup variables from QNames to stack frame |
| * indexes at stylesheet build time. |
| * @param vars List of QNames that correspond to variables. This list |
| * should be searched backwards for the first qualified name that |
| * corresponds to the variable reference qname. The position of the |
| * QName in the vector from the start of the vector will be its position |
| * in the stack frame (but variables above the globalsTop value will need |
| * to be offset to the current stack frame). |
| */ |
| public void fixupVariables(java.util.Vector vars, int globalsSize) |
| { |
| m_left.fixupVariables(vars, globalsSize); |
| m_right.fixupVariables(vars, globalsSize); |
| } |
| |
| |
| /** |
| * 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() |
| { |
| |
| if (null != m_left && m_left.canTraverseOutsideSubtree()) |
| return true; |
| |
| if (null != m_right && m_right.canTraverseOutsideSubtree()) |
| return true; |
| |
| return false; |
| } |
| |
| /** |
| * Set the left and right operand expressions for this operation. |
| * |
| * |
| * @param l The left expression operand. |
| * @param r The right expression operand. |
| */ |
| public void setLeftRight(Expression l, Expression r) |
| { |
| m_left = l; |
| m_right = r; |
| } |
| |
| /** |
| * Execute a binary operation by calling execute on each of the operands, |
| * and then calling the operate method on the derived class. |
| * |
| * |
| * @param xctxt The runtime execution context. |
| * |
| * @return The XObject result of the operation. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public XObject execute(XPathContext xctxt) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| XObject left = m_left.execute(xctxt); |
| XObject right = m_right.execute(xctxt); |
| |
| return operate(left, right); |
| } |
| |
| /** |
| * Apply the operation to two operands, and return the result. |
| * |
| * |
| * @param left non-null reference to the evaluated left operand. |
| * @param right non-null reference to the evaluated right operand. |
| * |
| * @return non-null reference to the XObject that represents the result of the operation. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public XObject operate(XObject left, XObject right) |
| throws javax.xml.transform.TransformerException |
| { |
| return null; // no-op |
| } |
| |
| /** @return the left operand of binary operation, as an Expression. |
| */ |
| public Expression getLeftOperand(){ |
| return m_left; |
| } |
| |
| /** @return the right operand of binary operation, as an Expression. |
| */ |
| public Expression getRightOperand(){ |
| return m_right; |
| } |
| |
| } |