Package com.icl.saxon.expr
Class NodeSetValue
- java.lang.Object
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- com.icl.saxon.expr.Expression
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- com.icl.saxon.expr.Value
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- com.icl.saxon.expr.NodeSetValue
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- Direct Known Subclasses:
EmptyNodeSet
,NodeSetExtent
,NodeSetIntent
,SingletonNodeSet
public abstract class NodeSetValue extends Value
A node-set value. We use this both for node-sets and node-lists. The node set will only be sorted into document order when requested (using sort() or evaluate()). This is an abstract class with a number of concrete implementations including NodeSetExtent (for extensional node-sets) and NodeSetIntent (for intensional node-sets).
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Field Summary
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Fields inherited from class com.icl.saxon.expr.Expression
staticContext
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Constructor Summary
Constructors Constructor Description NodeSetValue()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description abstract boolean
asBoolean()
Evaluate as a boolean.double
asNumber()
Evaluate as a number.abstract java.lang.String
asString()
Convert to string valueboolean
compare(int operator, Value other)
Test how a nodeset compares to another Value under a relational comparisonint
conversionPreference(java.lang.Class required)
Get conversion preference for this value to a Java class.java.lang.Object
convertToJava(java.lang.Class target)
Convert to Java object (for passing to external functions)void
display(int level)
Diagnostic print of expression structureabstract NodeEnumeration
enumerate()
Return an enumeration of this nodeset value.NodeEnumeration
enumerate(Context c, boolean sorted)
Return an enumeration of this nodeset value.boolean
equals(Value other)
Test whether a nodeset "equals" another ValueValue
evaluate(Context context)
Evaluate the Node Set.NodeSetValue
evaluateAsNodeSet(Context context)
Evaluate an expression as a NodeSet.abstract int
getCount()
Count the nodes in the node-set.int
getDataType()
Determine the data type of the expressionabstract NodeInfo
getFirst()
Get the first node in the nodeset (in document order)abstract boolean
isSorted()
Test whether the value is known to be sortedboolean
notEquals(Value other)
Test whether a nodeset "not-equals" another Valueabstract void
setSorted(boolean isSorted)
Set a flag to indicate whether the nodes are sorted.abstract NodeSetValue
sort()
Sort the nodes into document order.-
Methods inherited from class com.icl.saxon.expr.Value
getDependencies, inverse, numericCompare, reduce, simplify, stringToNumber
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Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsBoolean, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent
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Method Detail
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getDataType
public int getDataType()
Determine the data type of the expression- Specified by:
getDataType
in classExpression
- Returns:
- Value.NODESET
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evaluate
public Value evaluate(Context context) throws XPathException
Evaluate the Node Set. This guarantees to return the result in sorted order.- Overrides:
evaluate
in classValue
- Parameters:
context
- The context for evaluation (not used)- Returns:
- the value, unchanged
- Throws:
XPathException
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evaluateAsNodeSet
public NodeSetValue evaluateAsNodeSet(Context context) throws XPathException
Evaluate an expression as a NodeSet.- Overrides:
evaluateAsNodeSet
in classExpression
- Parameters:
context
- The context in which the expression is to be evaluated- Returns:
- the value of the expression, evaluated in the current context
- Throws:
XPathException
- when the expression does not return a nodeset.
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enumerate
public abstract NodeEnumeration enumerate() throws XPathException
Return an enumeration of this nodeset value. Unless sort() has been called the nodes can be in any order.- Throws:
XPathException
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enumerate
public NodeEnumeration enumerate(Context c, boolean sorted) throws XPathException
Return an enumeration of this nodeset value. This is to satisfy the interface for Expression.- Overrides:
enumerate
in classExpression
- Parameters:
context
- The context is ignored.sorted
- Indicates that the result must be in document order- Throws:
XPathException
- when the expression does not return a nodeset.
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setSorted
public abstract 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.- Parameters:
isSorted
- true if the caller wishes to assert that the nodes are in document order and do not need to be further sorted
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isSorted
public abstract boolean isSorted() throws XPathException
Test whether the value is known to be sorted- Returns:
- true if the value is known to be sorted in document order, false if it is not known whether it is sorted.
- Throws:
XPathException
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asString
public abstract java.lang.String asString() throws XPathException
Convert to string value- Specified by:
asString
in classValue
- Returns:
- the value of the first node in the node-set if there is one, otherwise an empty string
- Throws:
XPathException
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asNumber
public double asNumber() throws XPathException
Evaluate as a number.- Specified by:
asNumber
in classValue
- Returns:
- the number obtained by evaluating as a String and converting the string to a number
- Throws:
XPathException
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asBoolean
public abstract boolean asBoolean() throws XPathException
Evaluate as a boolean.- Specified by:
asBoolean
in classValue
- Returns:
- true if the node set is not empty
- Throws:
XPathException
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getCount
public abstract int getCount() throws XPathException
Count the nodes in the node-set. Note this will sort the node set if necessary, to make sure there are no duplicates.- Throws:
XPathException
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sort
public abstract NodeSetValue sort() throws XPathException
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)- Parameters:
controller
- The controller used to sort nodes into document order- Returns:
- the same NodeSetValue, after sorting. (The reason for returning this is that it makes life easier for the XSL compiler).
- Throws:
XPathException
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getFirst
public abstract NodeInfo getFirst() throws XPathException
Get the first node in the nodeset (in document order)- Returns:
- the first node
- Throws:
XPathException
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equals
public boolean equals(Value other) throws XPathException
Test whether a nodeset "equals" another Value- Overrides:
equals
in classValue
- Returns:
- a boolean giving the value of the expression, evaluated in the current context
- Throws:
XPathException
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notEquals
public boolean notEquals(Value other) throws XPathException
Test whether a nodeset "not-equals" another Value- Overrides:
notEquals
in classValue
- Returns:
- a boolean giving the value of the expression, evaluated in the current context
- Throws:
XPathException
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compare
public boolean compare(int operator, Value other) throws XPathException
Test how a nodeset compares to another Value under a relational comparison- Overrides:
compare
in classValue
- Parameters:
operator
- The comparison operator, one of Tokenizer.LE, Tokenizer.LT, Tokenizer.GE, Tokenizer.GT,- Throws:
XPathException
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display
public void display(int level)
Diagnostic print of expression structure- Specified by:
display
in classExpression
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conversionPreference
public int conversionPreference(java.lang.Class required)
Get conversion preference for this value to a Java class. A low result indicates higher preference.- Specified by:
conversionPreference
in classValue
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convertToJava
public java.lang.Object convertToJava(java.lang.Class target) throws XPathException
Convert to Java object (for passing to external functions)- Specified by:
convertToJava
in classValue
- Parameters:
target
- The class required by the external function- Returns:
- an object of the target class
- Throws:
XPathException
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