Package net.sf.saxon.expr
Class RootExpression
- java.lang.Object
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- net.sf.saxon.expr.ComputedExpression
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- net.sf.saxon.expr.SingleNodeExpression
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- net.sf.saxon.expr.RootExpression
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
public class RootExpression extends SingleNodeExpression
An expression whose value is always a set of nodes containing a single node, the document root. This corresponds to the XPath Expression "/", including the implicit "/" at the start of a path expression with a leading "/".- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
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Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors Constructor Description RootExpression()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
computeCardinality()
Specify that the expression returns a singletonvoid
display(int level, java.io.PrintStream out, Configuration config)
Diagnostic print of expression structureboolean
equals(java.lang.Object other)
Is this expression the same as another expression?int
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.ItemType
getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expressionNodeInfo
getNode(XPathContext context)
Return the first element selected by this Expressionint
hashCode()
get HashCode for comparing two expressions-
Methods inherited from class net.sf.saxon.expr.SingleNodeExpression
computeSpecialProperties, effectiveBooleanValue, evaluateItem, iterate, optimize, typeCheck
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Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterateSubExpressions, markTailFunctionCalls, process, promote, replaceSubExpression, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, simplify, suppressValidation, typeError
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Method Detail
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equals
public boolean equals(java.lang.Object other)
Is this expression the same as another expression?- Overrides:
equals
in classjava.lang.Object
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computeCardinality
public final int computeCardinality()
Specify that the expression returns a singleton- Overrides:
computeCardinality
in classSingleNodeExpression
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getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression- Specified by:
getItemType
in interfaceExpression
- Overrides:
getItemType
in classSingleNodeExpression
- Parameters:
th
-- Returns:
- Type.NODE
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hashCode
public int hashCode()
get HashCode for comparing two expressions- Overrides:
hashCode
in classjava.lang.Object
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getNode
public NodeInfo getNode(XPathContext context) throws XPathException
Return the first element selected by this Expression- Specified by:
getNode
in classSingleNodeExpression
- Parameters:
context
- The evaluation context- Returns:
- the NodeInfo of the first selected element, or null if no element is selected
- Throws:
XPathException
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getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as StaticProperty.VARIABLES and StaticProperty.CURRENT_NODE- Overrides:
getIntrinsicDependencies
in classSingleNodeExpression
- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
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display
public void display(int level, java.io.PrintStream out, Configuration config)
Diagnostic print of expression structure- Parameters:
level
- indentation level for this expressionout
- Output destination
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