## net.sf.saxon.expr
Class RootExpression

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

All Implemented Interfaces:
  Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, 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

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression
`EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD`

Constructor Summary
`RootExpression()`

Method Summary
`int` `computeCardinality()` Specify that the expression returns a singleton
`void` `display(int level, PrintStream out, Configuration config)` Diagnostic print of expression structure
`boolean` `equals(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 expression
`NodeInfo` `getNode(XPathContext context)` Return the first element selected by this Expression
`int` `hashCode()` get HashCode for comparing two expressions

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

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

`adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, evaluateAsString, getCardinality, getColumnNumber, getContainingProcedure, 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`

Methods inherited from class java.lang.Object
`getClass, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### RootExpression

    public RootExpression()

Method Detail

### equals

    public boolean equals(Object other)

  Is this expression the same as another expression?

  Overrides:
    `equals` in class `Object`

### computeCardinality

    public final int computeCardinality()

  Specify that the expression returns a singleton

  Overrides:
    `computeCardinality` in class `SingleNodeExpression`

### getItemType

    public ItemType getItemType(TypeHierarchy th)

  Determine the data type of the items returned by this expression

  Overrides:
    `getItemType` in class `SingleNodeExpression`
  Parameters:
    `th` -
  Returns:
    Type.NODE

### hashCode

    public int hashCode()

  get HashCode for comparing two expressions

  Overrides:
    `hashCode` in class `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

### display

    public void display(int level,
                        PrintStream out,
                        Configuration config)

  Diagnostic print of expression structure

  Specified by:
    `display` in class `Expression`
  Parameters:
    `level` - indentation level for this expression
    `out` - Output destination

Copyright (C) Michael H. Kay. All rights reserved.