Package 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
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public class RootExpression extends SingletonExpression
An expression whose value is always a set of nodes containing a single node, the document root.
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Field Summary
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Fields inherited from class com.icl.saxon.expr.Expression
staticContext
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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 void
display(int level)
Diagnostic print of expression structureboolean
evaluateAsBoolean(Context context)
Evaluate as a boolean.java.lang.String
evaluateAsString(Context context)
Evaluate as a stringint
getDependencies()
Determine which aspects of the context the expression depends on.NodeInfo
getNode(Context context)
Return the first element selected by this ExpressionExpression
reduce(int dependencies, Context context)
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.Expression
simplify()
Simplify an expression-
Methods inherited from class com.icl.saxon.expr.SingletonExpression
enumerate, evaluateAsNodeSet, isContextDocumentNodeSet, selectFirst
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Methods inherited from class com.icl.saxon.expr.NodeSetExpression
evaluate, getDataType, outputStringValue
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Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsNumber, getStaticContext, indent, make, setStaticContext, usesCurrent
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Method Detail
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simplify
public Expression simplify() throws XPathException
Simplify an expression- Overrides:
simplify
in classExpression
- Returns:
- the simplified expression
- Throws:
XPathException
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getNode
public NodeInfo getNode(Context context) throws XPathException
Return the first element selected by this Expression- Specified by:
getNode
in classSingletonExpression
- 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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evaluateAsString
public java.lang.String evaluateAsString(Context context) throws XPathException
Evaluate as a string- Overrides:
evaluateAsString
in classSingletonExpression
- Parameters:
context
- The context for evaluation- Returns:
- The concatenation of all the character data within the document
- Throws:
XPathException
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evaluateAsBoolean
public boolean evaluateAsBoolean(Context context) throws XPathException
Evaluate as a boolean.- Overrides:
evaluateAsBoolean
in classSingletonExpression
- Parameters:
context
- The context (not used)- Returns:
- true (always - because the nodeset is never empty)
- Throws:
XPathException
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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 classExpression
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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 classExpression
- 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
- Throws:
XPathException
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display
public void display(int level)
Diagnostic print of expression structure- Specified by:
display
in classExpression
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