RootExpression

java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.expr.SingleNodeExpression
  - - net.sf.saxon.expr.RootExpression

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, org.xml.sax.Locator
```
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

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Constructors
Constructor Description

RootExpression()

Constructors
Constructor	Description
`RootExpression()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`PathMap.PathMapNodeSet`	`addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)`	Add a representation of this expression to a PathMap.
`int`	`computeCardinality()`	Specify that the expression returns a singleton
`Expression`	`copy()`	Copy an expression.
`boolean`	`equals(java.lang.Object other)`	Is this expression the same as another expression?
`void`	`explain(ExpressionPresenter destination)`	Diagnostic print of expression structure.
`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 expression
`NodeInfo`	`getNode(XPathContext context)`	Return the first element selected by this Expression
`int`	`hashCode()`	get HashCode for comparing two expressions
`java.lang.String`	`toString()`	The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.

Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, iterateSubExpressions, markTailFunctionCalls, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, typeError

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from class net.sf.saxon.expr.SingleNodeExpression
computeSpecialProperties, effectiveBooleanValue, evaluateItem, iterate, optimize, typeCheck

- Constructor Detail
  - RootExpression
```
public RootExpression()
```
- Method Detail
  - equals
```
public boolean equals(java.lang.Object other)
```
    Is this expression the same as another expression?
    
    Overrides:
    
    equals in class java.lang.Object
  - computeCardinality
```
public final int computeCardinality()
```
    Specify that the expression returns a singleton
    
    Overrides:
    
    computeCardinality in class SingleNodeExpression
    
    Returns:
    
    the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE
  - getItemType
```
public ItemType getItemType(TypeHierarchy th)
```
    Determine the data type of the items returned by this expression
    
    Overrides:
    
    getItemType in class SingleNodeExpression
    
    Parameters:
    
    th - the type hierarchy cache
    
    Returns:
    
    Type.NODE
  - hashCode
```
public int hashCode()
```
    get HashCode for comparing two expressions
    
    Overrides:
    
    hashCode in class java.lang.Object
  - getNode
```
public NodeInfo getNode(XPathContext context)
                 throws XPathException
```
    Return the first element selected by this Expression
    
    Specified by:
    
    getNode in class SingleNodeExpression
    
    Parameters:
    
    context - The evaluation context
    
    Returns:
    
    the NodeInfo of the first selected element, or null if no element is selected
    
    Throws:
    
    XPathException
  - 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 class SingleNodeExpression
    
    Returns:
    
    a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
  - copy
```
public Expression copy()
```
    Copy an expression. This makes a deep copy.
    
    Specified by:
    
    copy in class Expression
    
    Returns:
    
    the copy of the original expression
  - addToPathMap
```
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
```
    Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.
    
    Overrides:
    
    addToPathMap in class Expression
    
    Parameters:
    
    pathMap - the PathMap to which the expression should be added
    
    pathMapNodeSet -
    
    Returns:
    
    the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression
  - toString
```
public java.lang.String toString()
```
    The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. In the case of XSLT instructions, the toString() method gives an abstracted view of the syntax
    
    Overrides:
    
    toString in class Expression
  - explain
```
public void explain(ExpressionPresenter destination)
```
    Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
    
    Specified by:
    
    explain in class Expression
    
    Parameters:
    
    destination - the expression presenter used to display the structure

Class RootExpression

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

Constructor Summary

Method Summary

Methods inherited from class net.sf.saxon.expr.Expression

Methods inherited from class java.lang.Object

Methods inherited from class net.sf.saxon.expr.SingleNodeExpression

Constructor Detail

RootExpression

Method Detail

equals

computeCardinality

getItemType

hashCode

getNode

getIntrinsicDependencies

copy

addToPathMap

toString

explain