org.apache.xpath.axes
Class PredicatedNodeTest

java.lang.Object
  org.apache.xpath.Expression
      org.apache.xpath.patterns.NodeTest
          org.apache.xpath.axes.PredicatedNodeTest

All Implemented Interfaces:

ExpressionNode, Serializable, javax.xml.transform.SourceLocator, SubContextList, XPathVisitable

Direct Known Subclasses:

AxesWalker, LocPathIterator

public abstract class PredicatedNodeTest

extends NodeTest

implements SubContextList

See Also:

Serialized Form

Nested Class Summary

(package private) class

PredicatedNodeTest.PredOwner

Field Summary

(package private) static boolean	DEBUG_PREDICATECOUNTING If true, diagnostic messages about predicate execution will be posted.
protected boolean	m_foundLast This is true if nextNode returns null.
protected LocPathIterator	m_lpi The owning location path iterator.
protected int	m_predCount
(package private) int	m_predicateIndex Which predicate we are executing.
private Expression[]	m_predicates The list of predicate expressions.
protected int[]	m_proximityPositions An array of counts that correspond to the number of predicates the step contains.

Fields inherited from class org.apache.xpath.patterns.NodeTest

m_name, m_whatToShow, SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, SUPPORTS_PRE_STRIPPING, WILD

Fields inherited from class org.apache.xpath.Expression

Constructor Summary

(package private)	PredicatedNodeTest() Construct an AxesWalker.
(package private)	PredicatedNodeTest(LocPathIterator locPathIterator) Construct an AxesWalker using a LocPathIterator.

Method Summary

short	acceptNode(int n) Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator.
void	callPredicateVisitors(XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
Object	clone() Get a cloned PrdicatedNodeTest.
protected void	countProximityPosition(int i) Count forward one proximity position.
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
(package private) boolean	executePredicates(int context, XPathContext xctxt) Process the predicates.
void	fixupVariables(Vector vars, int globalsSize) This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
abstract int	getLastPos(XPathContext xctxt) Get the index of the last node that can be itterated to.
LocPathIterator	getLocPathIterator() Get the owning location path iterator.
Expression	getPredicate(int index) Get a predicate expression at the given index.
int	getPredicateCount() Get the number of predicates that this walker has.
int	getPredicateIndex() Get which predicate is executing.
int	getProximityPosition() Get the current sub-context position.
protected int	getProximityPosition(int predicateIndex) Get the current sub-context position.
int	getProximityPosition(XPathContext xctxt) Get the current sub-context position.
protected void	initPredicateInfo(Compiler compiler, int opPos) Init predicate info.
void	initProximityPosition(int i) Init the proximity position to zero for a forward axes.
boolean	isReverseAxes() Tells if this is a reverse axes.
protected String	nodeToString(int n) Diagnostics.
private void	readObject(ObjectInputStream stream) Read the object from a serialization stream.
void	resetProximityPositions() Reset the proximity positions counts.
void	setLocPathIterator(LocPathIterator li) Set the location path iterator owner for this walker.
void	setPredicateCount(int count) Set the number of predicates that this walker has.

Methods inherited from class org.apache.xpath.patterns.NodeTest

calcScore, callVisitors, debugWhatToShow, execute, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, getWhatToShow, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow

Methods inherited from class org.apache.xpath.Expression

asIterator, asIteratorRaw, asNode, assertion, bool, error, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isSameClass, isStableNumber, num, warn, xstr

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_predCount

protected int m_predCount

m_foundLast

protected transient boolean m_foundLast

This is true if nextNode returns null.

m_lpi

protected LocPathIterator m_lpi

The owning location path iterator.

m_predicateIndex

transient int m_predicateIndex

Which predicate we are executing.

m_predicates

private Expression[] m_predicates

The list of predicate expressions. Is static and does not need to be deep cloned.

m_proximityPositions

protected transient int[] m_proximityPositions

An array of counts that correspond to the number of predicates the step contains.

DEBUG_PREDICATECOUNTING

static final boolean DEBUG_PREDICATECOUNTING

If true, diagnostic messages about predicate execution will be posted.

See Also:

Constant Field Values

Constructor Detail

PredicatedNodeTest

PredicatedNodeTest(LocPathIterator locPathIterator)

Construct an AxesWalker using a LocPathIterator.

Parameters:

locPathIterator - non-null reference to the parent iterator.

PredicatedNodeTest

PredicatedNodeTest()

Construct an AxesWalker. The location path iterator will have to be set before use.

Method Detail

readObject

private void readObject(ObjectInputStream stream)
                 throws IOException,
                        javax.xml.transform.TransformerException

Read the object from a serialization stream.

Parameters:

stream - Input stream to read from

Throws:

IOException

javax.xml.transform.TransformerException

clone

public Object clone()
             throws CloneNotSupportedException

Get a cloned PrdicatedNodeTest.

Overrides:

clone in class Object

Returns:

A new PredicatedNodeTest that can be used without mutating this one.

Throws:

CloneNotSupportedException

See Also:

Cloneable

getPredicateCount

public int getPredicateCount()

Get the number of predicates that this walker has.

Returns:

the number of predicates that this walker has.

setPredicateCount

public void setPredicateCount(int count)

Set the number of predicates that this walker has. This does more that one would think, as it creates a new predicate array of the size of the count argument, and copies count predicates into the new one from the old, and then reassigns the predicates value. All this to keep from having to have a predicate count value.

Parameters:

count - The number of predicates, which must be equal or less than the existing count.

initPredicateInfo

protected void initPredicateInfo(Compiler compiler,
                                 int opPos)
                          throws javax.xml.transform.TransformerException

Init predicate info.

Parameters:

compiler - The Compiler object that has information about this walker in the op map.

opPos - The op code position of this location step.

Throws:

javax.xml.transform.TransformerException

getPredicate

public Expression getPredicate(int index)

Get a predicate expression at the given index.

Parameters:

index - Index of the predicate.

Returns:

A predicate expression.

getProximityPosition

public int getProximityPosition()

Get the current sub-context position.

Returns:

The node position of this walker in the sub-context node list.

getProximityPosition

public int getProximityPosition(XPathContext xctxt)

Get the current sub-context position.

Specified by:

getProximityPosition in interface SubContextList

Parameters:

xctxt - The XPath runtime context.

Returns:

The node position of this walker in the sub-context node list.

getLastPos

public abstract int getLastPos(XPathContext xctxt)

Get the index of the last node that can be itterated to.

Specified by:

getLastPos in interface SubContextList

Parameters:

xctxt - XPath runtime context.

Returns:

the index of the last node that can be itterated to.

getProximityPosition

protected int getProximityPosition(int predicateIndex)

Get the current sub-context position.

Parameters:

predicateIndex - The index of the predicate where the proximity should be taken from.

Returns:

The node position of this walker in the sub-context node list.

resetProximityPositions

public void resetProximityPositions()

Reset the proximity positions counts.

initProximityPosition

public void initProximityPosition(int i)
                           throws javax.xml.transform.TransformerException

Init the proximity position to zero for a forward axes.

Parameters:

i - The index into the m_proximityPositions array.

Throws:

javax.xml.transform.TransformerException

countProximityPosition

protected void countProximityPosition(int i)

Count forward one proximity position.

Parameters:

i - The index into the m_proximityPositions array, where the increment will occur.

isReverseAxes

public boolean isReverseAxes()

Tells if this is a reverse axes.

Returns:

false, unless a derived class overrides.

getPredicateIndex

public int getPredicateIndex()

Get which predicate is executing.

Returns:

The current predicate index, or -1 if no predicate is executing.

executePredicates

boolean executePredicates(int context,
                          XPathContext xctxt)
                    throws javax.xml.transform.TransformerException

Process the predicates.

Parameters:

context - The current context node.

xctxt - The XPath runtime context.

Returns:

the result of executing the predicate expressions.

Throws:

javax.xml.transform.TransformerException

fixupVariables

public void fixupVariables(Vector vars,
                           int globalsSize)

This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.

Overrides:

fixupVariables in class NodeTest

Parameters:

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).

nodeToString

protected String nodeToString(int n)

Diagnostics.

Parameters:

n - Node to give diagnostic information about, or null.

Returns:

Informative string about the argument.

acceptNode

public short acceptNode(int n)

Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator. This function will be called by the implementation of TreeWalker and NodeIterator; it is not intended to be called directly from user code.

Parameters:

n - The node to check to see if it passes the filter or not.

Returns:

a constant to determine whether the node is accepted, rejected, or skipped, as defined above .

getLocPathIterator

public LocPathIterator getLocPathIterator()

Get the owning location path iterator.

Returns:

the owning location path iterator, which should not be null.

setLocPathIterator

public void setLocPathIterator(LocPathIterator li)

Set the location path iterator owner for this walker. Besides initialization, this function is called during cloning operations.

Parameters:

li - non-null reference to the owning location path iterator.

canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()

Tell if this expression or it's subexpressions can traverse outside the current subtree.

Overrides:

canTraverseOutsideSubtree in class Expression

Returns:

true if traversal outside the context node's subtree can occur.

callPredicateVisitors

public void callPredicateVisitors(XPathVisitor visitor)

This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Parameters:

visitor - The visitor whose appropriate method will be called.

deepEquals

public boolean deepEquals(Expression expr)

Description copied from class: Expression

Compare this object with another object and see if they are equal, include the sub heararchy.

Overrides:

deepEquals in class NodeTest

See Also:

Expression.deepEquals(Expression)