Class RootExpression

java.lang.Object
com.icl.saxon.expr.Expression
com.icl.saxon.expr.NodeSetExpression
com.icl.saxon.expr.SingletonExpression
com.icl.saxon.expr.RootExpression
public class RootExpression extends SingletonExpression
An expression whose value is always a set of nodes containing a single node, the document root.

  • Constructor Details

    • RootExpression

      public RootExpression()

  • Method Details

    • simplify

      public Expression simplify() throws XPathException
      Simplify an expression
      Overrides:
      simplify in class Expression
      Returns:
      the simplified expression
      Throws:
      XPathException

    • getNode

      public NodeInfo getNode(Context context) throws XPathException
      Return the first element selected by this Expression
      Specified by:
      getNode in class SingletonExpression
      Parameters:
      context - The evaluation context
      Returns:
      the NodeInfo of the first selected element, or null if no element is selected
      Throws:
      XPathException

    • evaluateAsString

      public String evaluateAsString(Context context) throws XPathException
      Evaluate as a string
      Overrides:
      evaluateAsString in class SingletonExpression
      Parameters:
      context - The context for evaluation
      Returns:
      The concatenation of all the character data within the document
      Throws:
      XPathException

    • evaluateAsBoolean

      public boolean evaluateAsBoolean(Context context) throws XPathException
      Evaluate as a boolean.
      Overrides:
      evaluateAsBoolean in class SingletonExpression
      Parameters:
      context - The context (not used)
      Returns:
      true (always - because the nodeset is never empty)
      Throws:
      XPathException

    • getDependencies

      public int getDependencies()
      Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE
      Specified by:
      getDependencies in class Expression

    • reduce

      public Expression reduce(int dependencies, Context context) throws XPathException
      Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
      Specified by:
      reduce in class Expression
      Parameters:
      dependencies - The dependencies to be removed
      context - The context to be used for the partial evaluation
      Returns:
      a new expression that does not have any of the specified dependencies
      Throws:
      XPathException

    • display

      public void display(int level)
      Diagnostic print of expression structure
      Specified by:
      display in class Expression