| /* |
| * 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: Operation.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xpath.operations; |
| |
| 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 |
| { |
| static final long serialVersionUID = -3037139537171050430L; |
| |
| /** 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 org.apache.xpath.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; |
| } |
| } |