Package net.sf.saxon.tree.linked
Class TreeEnumeration
- java.lang.Object
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- net.sf.saxon.tree.linked.TreeEnumeration
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- All Implemented Interfaces:
SequenceIterator
,AxisIterator
,LookaheadIterator
,UnfailingIterator
- Direct Known Subclasses:
AncestorEnumeration
,ChildEnumeration
,DescendantEnumeration
,FollowingEnumeration
,FollowingSiblingEnumeration
,PrecedingEnumeration
,PrecedingOrAncestorEnumeration
,PrecedingSiblingEnumeration
abstract class TreeEnumeration extends java.lang.Object implements AxisIterator, LookaheadIterator
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Constructor Summary
Constructors Constructor Description TreeEnumeration(NodeImpl origin, NodeTest nodeTest)
Create an axis enumeration for a given type and name of node, from a given origin node
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected void
advance()
Advance along the axis until a node is found that matches the required criteriaValue
atomize()
Return the atomized value of the current node.void
close()
Close the iterator.protected boolean
conforms(NodeImpl node)
Test whether a node conforms to the node type and name constraints.NodeInfo
current()
Return the current Itemint
getProperties()
Get properties of this iterator, as a bit-significant integer.java.lang.CharSequence
getStringValue()
Return the string value of the current node.boolean
hasNext()
Determine whether there are more items to come.AxisIterator
iterateAxis(byte axis, NodeTest test)
Return an iterator over an axis, starting at the current node.boolean
moveNext()
Move to the next node, without returning it.NodeInfo
next()
Return the next node in the enumerationint
position()
Return the current positionprotected abstract void
step()
Advance one step along the axis: the resulting node might not meet the required criteria for inclusion-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface net.sf.saxon.tree.iter.AxisIterator
getAnother
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Constructor Detail
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TreeEnumeration
public TreeEnumeration(NodeImpl origin, NodeTest nodeTest)
Create an axis enumeration for a given type and name of node, from a given origin node- Parameters:
origin
- the node from which the axis originatesnodeTest
- test to be satisfied by the returned nodes, or null if all nodes are to be returned.
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Method Detail
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conforms
protected boolean conforms(NodeImpl node)
Test whether a node conforms to the node type and name constraints. Note that this returns true if the supplied node is null, this is a way of terminating a loop.- Parameters:
node
- the node to be tested- Returns:
- true if the node matches the requested node type and name
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advance
protected final void advance()
Advance along the axis until a node is found that matches the required criteria
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step
protected abstract void step()
Advance one step along the axis: the resulting node might not meet the required criteria for inclusion
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hasNext
public boolean hasNext()
Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.- Specified by:
hasNext
in interfaceLookaheadIterator
- Returns:
- true if there are more items in the sequence
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moveNext
public boolean moveNext()
Move to the next node, without returning it. Returns true if there is a next node, false if the end of the sequence has been reached. After calling this method, the current node may be retrieved using the current() function.- Specified by:
moveNext
in interfaceAxisIterator
- Returns:
- true if there is a next node, false if the end of the sequence has been reached
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next
public final NodeInfo next()
Return the next node in the enumeration- Specified by:
next
in interfaceAxisIterator
- Specified by:
next
in interfaceSequenceIterator
- Specified by:
next
in interfaceUnfailingIterator
- Returns:
- the next Item. If there are no more nodes, return null.
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current
public final NodeInfo current()
Return the current Item- Specified by:
current
in interfaceAxisIterator
- Specified by:
current
in interfaceSequenceIterator
- Specified by:
current
in interfaceUnfailingIterator
- Returns:
- the current item, that is, the item most recently returned by next()
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position
public final int position()
Return the current position- Specified by:
position
in interfaceSequenceIterator
- Specified by:
position
in interfaceUnfailingIterator
- Returns:
- the position of the current item (the item most recently returned by next()), starting at 1 for the first node
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close
public void close()
Description copied from interface:SequenceIterator
Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)
- Specified by:
close
in interfaceSequenceIterator
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iterateAxis
public AxisIterator iterateAxis(byte axis, NodeTest test)
Return an iterator over an axis, starting at the current node.- Specified by:
iterateAxis
in interfaceAxisIterator
- Parameters:
axis
- the axis to iterate over, using a constant such asAxis.CHILD
test
- a predicate to apply to the nodes before returning them.- Returns:
- an iterator over an axis, starting at the current node
- Throws:
java.lang.NullPointerException
- if there is no current node
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atomize
public Value atomize() throws XPathException
Return the atomized value of the current node.- Specified by:
atomize
in interfaceAxisIterator
- Returns:
- the atomized value.
- Throws:
java.lang.NullPointerException
- if there is no current nodeXPathException
- if the current node cannot be atomized, for example because it is an element node with element-only content.
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getStringValue
public java.lang.CharSequence getStringValue()
Return the string value of the current node.- Specified by:
getStringValue
in interfaceAxisIterator
- Returns:
- the string value, as an instance of CharSequence.
- Throws:
java.lang.NullPointerException
- if there is no current node
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getProperties
public int getProperties()
Get properties of this iterator, as a bit-significant integer.- Specified by:
getProperties
in interfaceSequenceIterator
- Returns:
- the properties of this iterator. This will be some combination of
properties such as
SequenceIterator.GROUNDED
,SequenceIterator.LAST_POSITION_FINDER
, andSequenceIterator.LOOKAHEAD
. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.
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