com.icl.saxon.expr
Class NodeSetExtent

java.lang.Object
  com.icl.saxon.expr.Expression
      com.icl.saxon.expr.Value
          com.icl.saxon.expr.NodeSetValue
              com.icl.saxon.expr.NodeSetExtent

All Implemented Interfaces:

org.w3c.dom.NodeList, Sortable

public final class NodeSetExtent

extends NodeSetValue

implements Sortable, org.w3c.dom.NodeList

A node-set value implemented extensionally. This class also implements the DOM NodeList interface - though this will only work if the nodes themselves implement the DOM Node interface (which is true of the two Saxon tree models, but not necessarily of all possible implementations).

Field Summary

Fields inherited from class com.icl.saxon.expr.Value

ANY, BOOLEAN, NODESET, NUMBER, OBJECT, STRING

Fields inherited from class com.icl.saxon.expr.Expression

staticContext

Constructor Summary

NodeSetExtent(NodeEnumeration enm, NodeOrderComparer comparer)
Construct a node-set containing all the nodes in a NodeEnumeration.

NodeSetExtent(NodeInfo[] nodes, NodeOrderComparer comparer)
Construct a node-set given the set of nodes as an array

NodeSetExtent(NodeOrderComparer comparer)
Construct an empty node set

NodeSetExtent(java.util.Vector nodes, NodeOrderComparer comparer)
Construct a node-set given the set of nodes as a Vector

Method Summary

void	append(NodeInfo node) Append a node to the node-set.
boolean	asBoolean() Evaluate as a boolean.
java.lang.String	asString() Convert to string value
int	compare(int a, int b) Compare two nodes in document sequence (needed to implement the Sortable interface)
NodeEnumeration	enumerate() Return an enumeration of this nodeset value.
int	getCount() Count the nodes in the node-set.
NodeInfo	getFirst() Get the first node in the nodeset (in document order)
int	getLength() return the number of nodes in the list (DOM method)
boolean	isSorted() Test whether the value is known to be sorted
org.w3c.dom.Node	item(int index) Return the n'th item in the list (DOM method)
NodeInfo	selectFirst(Context context) Return the first node in the nodeset (in document order)
void	setSorted(boolean isSorted) Set a flag to indicate whether the nodes are sorted.
Expression	simplify() Simplify the expression
NodeSetValue	sort() Sort the nodes into document order.
void	swap(int a, int b) Swap two nodes (needed to implement the Sortable interface)

Methods inherited from class com.icl.saxon.expr.NodeSetValue

asNumber, compare, conversionPreference, convertToJava, display, enumerate, equals, evaluate, evaluateAsNodeSet, getDataType, notEquals

Methods inherited from class com.icl.saxon.expr.Value

getDependencies, inverse, numericCompare, reduce, stringToNumber

Methods inherited from class com.icl.saxon.expr.Expression

containsReferences, evaluateAsBoolean, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeSetExtent

public NodeSetExtent(NodeOrderComparer comparer)

Construct an empty node set

NodeSetExtent

public NodeSetExtent(NodeInfo[] nodes,
                     NodeOrderComparer comparer)

Construct a node-set given the set of nodes as an array

Parameters:

nodes - An array whose elements must be NodeInfo objects

comparer - Comparer used for sorting into document order

NodeSetExtent

public NodeSetExtent(java.util.Vector nodes,
                     NodeOrderComparer comparer)

Construct a node-set given the set of nodes as a Vector

Parameters:

nodes - a Vector whose elements must be NodeInfo objects

comparer - Comparer used for sorting into document order

NodeSetExtent

public NodeSetExtent(NodeEnumeration enm,
                     NodeOrderComparer comparer)
              throws XPathException

Construct a node-set containing all the nodes in a NodeEnumeration.

Parameters:

enm - The supplied node enumeration. This must be positioned at the start, so that hasMoreElements() returns true if there are any nodes in the node-set, and nextElement() returns the first node.

comparer - Comparer used for sorting into document order

Method Detail

append

public void append(NodeInfo node)

Append a node to the node-set. This is used only when building indexes. The node-set must be sorted; the new node must follow the others in document order. The new node is not added if it is the same as the last node currently in the node-set.

simplify

public Expression simplify()

Simplify the expression

Overrides:

simplify in class Value

Returns:

the simplified expression

setSorted

public void setSorted(boolean isSorted)

Set a flag to indicate whether the nodes are sorted. Used when the creator of the node-set knows that they are already in document order.

Specified by:

setSorted in class NodeSetValue

Parameters:

isSorted - true if the caller wishes to assert that the nodes are in document order and do not need to be further sorted

isSorted

public boolean isSorted()

Test whether the value is known to be sorted

Specified by:

isSorted in class NodeSetValue

Returns:

true if the value is known to be sorted in document order, false if it is not known whether it is sorted.

asString

public java.lang.String asString()

Convert to string value

Specified by:

asString in class NodeSetValue

Returns:

the value of the first node in the node-set if there is one, otherwise an empty string

asBoolean

public boolean asBoolean()
                  throws XPathException

Evaluate as a boolean.

Specified by:

asBoolean in class NodeSetValue

Returns:

true if the node set is not empty

Throws:

XPathException

getCount

public int getCount()

Count the nodes in the node-set. Note this will sort the node set if necessary, to make sure there are no duplicates.

Specified by:

getCount in class NodeSetValue

sort

public NodeSetValue sort()

Sort the nodes into document order. This does nothing if the nodes are already known to be sorted; to force a sort, call setSorted(false)

Specified by:

sort in class NodeSetValue

Returns:

the same NodeSetValue, after sorting. (The reason for returning this is that it makes life easier for the XSL compiler).

getFirst

public NodeInfo getFirst()

Get the first node in the nodeset (in document order)

Specified by:

getFirst in class NodeSetValue

Returns:

the first node, or null if the nodeset is empty

selectFirst

public NodeInfo selectFirst(Context context)

Return the first node in the nodeset (in document order)

Parameters:

context - The context for the evaluation: not used

Returns:

the NodeInfo of the first node in document order, or null if the node-set is empty.

enumerate

public NodeEnumeration enumerate()

Return an enumeration of this nodeset value.

Specified by:

enumerate in class NodeSetValue

getLength

public int getLength()

return the number of nodes in the list (DOM method)

Specified by:

getLength in interface org.w3c.dom.NodeList

item

public org.w3c.dom.Node item(int index)

Return the n'th item in the list (DOM method)

Specified by:

item in interface org.w3c.dom.NodeList

compare

public int compare(int a,
                   int b)

Compare two nodes in document sequence (needed to implement the Sortable interface)

Specified by:

compare in interface Sortable

Returns:

<0 if obj[a]0 if obj[a]>obj[b]

swap

public void swap(int a,
                 int b)

Swap two nodes (needed to implement the Sortable interface)

Specified by:

swap in interface Sortable