## net.sf.saxon.functions
Class Available

    java.lang.Object
      net.sf.saxon.expr.Expression
          net.sf.saxon.expr.FunctionCall
              net.sf.saxon.functions.SystemFunction
                  net.sf.saxon.functions.Available

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

    public class Available

extends SystemFunction
implements XSLTFunction

This class supports the XSLT element-available and function-available functions.

See Also:
  Serialized Form

Field Summary
`static int` `ELEMENT_AVAILABLE`
`static int` `FUNCTION_AVAILABLE`
`static int` `TYPE_AVAILABLE`

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

Constructor Summary
`Available()`

Method Summary
`void` `checkArguments(StaticContext env)` Method called during static type checking
`Item` `evaluateItem(XPathContext context)` Run-time evaluation.
`Expression` `preEvaluate(StaticContext env)` preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)

Methods inherited from class net.sf.saxon.functions.SystemFunction
`computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, main, makeSystemFunction, optimize, setDetails`

Methods inherited from class net.sf.saxon.expr.FunctionCall
`getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplify, typeCheck`

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

`adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation`

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

Field Detail

### ELEMENT_AVAILABLE

    public static final int ELEMENT_AVAILABLE

See Also:
  Constant Field Values

### FUNCTION_AVAILABLE

    public static final int FUNCTION_AVAILABLE

See Also:
  Constant Field Values

### TYPE_AVAILABLE

    public static final int TYPE_AVAILABLE

See Also:
  Constant Field Values

Constructor Detail

### Available

    public Available()

Method Detail

### checkArguments

    public void checkArguments(StaticContext env)
                        throws XPathException

  Description copied from class: `SystemFunction`
  Method called during static type checking

  Overrides:
    `checkArguments` in class `SystemFunction`
  Throws:
    `XPathException`

### preEvaluate

    public Expression preEvaluate(StaticContext env)
                           throws XPathException

  preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)

  Overrides:
    `preEvaluate` in class `FunctionCall`
  Throws:
    `XPathException`

### evaluateItem

    public Item evaluateItem(XPathContext context)
                      throws XPathException

  Run-time evaluation. This is the only thing in the spec that requires information about in-scope functions to be available at run-time. However, we keep it because it's handy for some other things such as saxon:evaluate().

  Specified by:
    `evaluateItem` in interface `EvaluableItem`
  Overrides:
    `evaluateItem` in class `Expression`
  Parameters:
    `context` - The context in which the expression is to be evaluated
  Returns:
    the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
  Throws:
    `XPathException` - if any dynamic error occurs evaluating the expression

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