- /*
- * 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 java.util.Vector;
-
- 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;
-
- /**
- * The baseclass for a binary operation.
- */
- public class Operation extends Expression implements ExpressionOwner
- {
-
- /** 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;
- l.exprSetParent(this);
- r.exprSetParent(this);
- }
-
- /**
- * 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, true);
- XObject right = m_right.execute(xctxt, true);
-
- XObject result = operate(left, right);
- left.detach();
- right.detach();
- return result;
- }
-
- /**
- * 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;
- }
-
- class LeftExprOwner implements ExpressionOwner
- {
- /**
- * @see ExpressionOwner#getExpression()
- */
- public Expression getExpression()
- {
- return m_left;
- }
-
- /**
- * @see ExpressionOwner#setExpression(Expression)
- */
- public void setExpression(Expression exp)
- {
- exp.exprSetParent(Operation.this);
- m_left = exp;
- }
- }
-
- /**
- * @see XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
- */
- public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
- {
- if(visitor.visitBinaryOperation(owner, this))
- {
- m_left.callVisitors(new LeftExprOwner(), visitor);
- m_right.callVisitors(this, visitor);
- }
- }
-
- /**
- * @see ExpressionOwner#getExpression()
- */
- public Expression getExpression()
- {
- return m_right;
- }
-
- /**
- * @see ExpressionOwner#setExpression(Expression)
- */
- public void setExpression(Expression exp)
- {
- exp.exprSetParent(this);
- m_right = exp;
- }
-
- /**
- * @see Expression#deepEquals(Expression)
- */
- public boolean deepEquals(Expression expr)
- {
- if(!isSameClass(expr))
- return false;
-
- if(!m_left.deepEquals(((Operation)expr).m_left))
- return false;
-
- if(!m_right.deepEquals(((Operation)expr).m_right))
- return false;
-
- return true;
- }
- }