com.icl.saxon.expr
Class RootExpression
java.lang.Object
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+--com.icl.saxon.expr.Expression
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+--com.icl.saxon.expr.NodeSetExpression
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+--com.icl.saxon.expr.SingletonExpression
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+--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.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
RootExpression
public RootExpression()
simplify
public Expression simplify()
throws XPathException
- Simplify an expression
- Overrides:
simplify
in class Expression
- Returns:
- the simplified expression
getNode
public NodeInfo getNode(Context context)
throws XPathException
- Return the first element selected by this Expression
- Overrides:
getNode
in class SingletonExpression
- Parameters:
context
- The evaluation context- Returns:
- the NodeInfo of the first selected element, or null if no element
is selected
evaluateAsString
public java.lang.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
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)
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
- Overrides:
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.
- Overrides:
reduce
in class Expression
- Parameters:
dependencies
- The dependencies to be removedcontext
- The context to be used for the partial evaluation- Returns:
- a new expression that does not have any of the specified
dependencies
display
public void display(int level)
- Diagnostic print of expression structure
- Overrides:
display
in class Expression