/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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: FilterExprIteratorSimple.java,v 1.2.4.2 2005/09/14 19:45:21 jeffsuttor Exp $
*/
package com.sun.org.apache.xpath.internal.axes;
import com.sun.org.apache.xml.internal.dtm.Axis;
import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xpath.internal.Expression;
import com.sun.org.apache.xpath.internal.ExpressionOwner;
import com.sun.org.apache.xpath.internal.VariableStack;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.XPathVisitor;
import com.sun.org.apache.xpath.internal.objects.XNodeSet;
/**
* Class to use for one-step iteration that doesn't have a predicate, and
* doesn't need to set the context.
*/
public class FilterExprIteratorSimple extends LocPathIterator
{
static final long serialVersionUID = -6978977187025375579L;
/** The contained expression. Should be non-null.
* @serial */
private Expression m_expr;
/** The result of executing m_expr. Needs to be deep cloned on clone op. */
transient private XNodeSet m_exprObj;
private boolean m_mustHardReset = false;
private boolean m_canDetachNodeset = true;
/**
* Create a FilterExprIteratorSimple object.
*
*/
public FilterExprIteratorSimple()
{
super(null);
}
/**
* Create a FilterExprIteratorSimple object.
*
*/
public FilterExprIteratorSimple(Expression expr)
{
super(null);
m_expr = expr;
}
/**
* Initialize the context values for this expression
* after it is cloned.
*
* @param context The XPath runtime context for this
* transformation.
*/
public void setRoot(int context, Object environment)
{
super.setRoot(context, environment);
m_exprObj = executeFilterExpr(context, m_execContext, getPrefixResolver(),
getIsTopLevel(), m_stackFrame, m_expr);
}
/**
* Execute the expression. Meant for reuse by other FilterExpr iterators
* that are not derived from this object.
*/
public static XNodeSet executeFilterExpr(int context, XPathContext xctxt,
PrefixResolver prefixResolver,
boolean isTopLevel,
int stackFrame,
Expression expr )
throws com.sun.org.apache.xml.internal.utils.WrappedRuntimeException
{
PrefixResolver savedResolver = xctxt.getNamespaceContext();
XNodeSet result = null;
try
{
xctxt.pushCurrentNode(context);
xctxt.setNamespaceContext(prefixResolver);
// The setRoot operation can take place with a reset operation,
// and so we may not be in the context of LocPathIterator#nextNode,
// so we have to set up the variable context, execute the expression,
// and then restore the variable context.
if (isTopLevel)
{
// System.out.println("calling m_expr.execute(getXPathContext())");
VariableStack vars = xctxt.getVarStack();
// These three statements need to be combined into one operation.
int savedStart = vars.getStackFrame();
vars.setStackFrame(stackFrame);
result = (com.sun.org.apache.xpath.internal.objects.XNodeSet) expr.execute(xctxt);
result.setShouldCacheNodes(true);
// These two statements need to be combined into one operation.
vars.setStackFrame(savedStart);
}
else
result = (com.sun.org.apache.xpath.internal.objects.XNodeSet) expr.execute(xctxt);
}
catch (javax.xml.transform.TransformerException se)
{
// TODO: Fix...
throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(se);
}
finally
{
xctxt.popCurrentNode();
xctxt.setNamespaceContext(savedResolver);
}
return result;
}
/**
* Returns the next node in the set and advances the position of the
* iterator in the set. After a NodeIterator is created, the first call
* to nextNode() returns the first node in the set.
*
* @return The next <code>Node</code> in the set being iterated over, or
* <code>null</code> if there are no more members in that set.
*/
public int nextNode()
{
if(m_foundLast)
return DTM.NULL;
int next;
if (null != m_exprObj)
{
m_lastFetched = next = m_exprObj.nextNode();
}
else
m_lastFetched = next = DTM.NULL;
// m_lastFetched = next;
if (DTM.NULL != next)
{
m_pos++;
return next;
}
else
{
m_foundLast = true;
return DTM.NULL;
}
}
/**
* Detaches the walker from the set which it iterated over, releasing
* any computational resources and placing the iterator in the INVALID
* state.
*/
public void detach()
{
if(m_allowDetach)
{
super.detach();
m_exprObj.detach();
m_exprObj = null;
}
}
/**
* 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)
{
super.fixupVariables(vars, globalsSize);
m_expr.fixupVariables(vars, globalsSize);
}
/**
* Get the inner contained expression of this filter.
*/
public Expression getInnerExpression()
{
return m_expr;
}
/**
* Set the inner contained expression of this filter.
*/
public void setInnerExpression(Expression expr)
{
expr.exprSetParent(this);
m_expr = expr;
}
/**
* Get the analysis bits for this walker, as defined in the WalkerFactory.
* @return One of WalkerFactory#BIT_DESCENDANT, etc.
*/
public int getAnalysisBits()
{
if (null != m_expr && m_expr instanceof PathComponent)
{
return ((PathComponent) m_expr).getAnalysisBits();
}
return WalkerFactory.BIT_FILTER;
}
/**
* Returns true if all the nodes in the iteration well be returned in document
* order.
* Warning: This can only be called after setRoot has been called!
*
* @return true as a default.
*/
public boolean isDocOrdered()
{
return m_exprObj.isDocOrdered();
}
class filterExprOwner implements ExpressionOwner
{
/**
* @see ExpressionOwner#getExpression()
*/
public Expression getExpression()
{
return m_expr;
}
/**
* @see ExpressionOwner#setExpression(Expression)
*/
public void setExpression(Expression exp)
{
exp.exprSetParent(FilterExprIteratorSimple.this);
m_expr = exp;
}
}
/**
* This will traverse the heararchy, calling the visitor for
* each member. If the called visitor method returns
* false, the subtree should not be called.
*
* @param visitor The visitor whose appropriate method will be called.
*/
public void callPredicateVisitors(XPathVisitor visitor)
{
m_expr.callVisitors(new filterExprOwner(), visitor);
super.callPredicateVisitors(visitor);
}
/**
* @see Expression#deepEquals(Expression)
*/
public boolean deepEquals(Expression expr)
{
if (!super.deepEquals(expr))
return false;
FilterExprIteratorSimple fet = (FilterExprIteratorSimple) expr;
if (!m_expr.deepEquals(fet.m_expr))
return false;
return true;
}
/**
* Returns the axis being iterated, if it is known.
*
* @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple
* types.
*/
public int getAxis()
{
if(null != m_exprObj)
return m_exprObj.getAxis();
else
return Axis.FILTEREDLIST;
}
}