net.sf.saxon.functions
public class ExtensionFunctionCall extends FunctionCall
Note that the binding of an XPath function call to a Java method is done in class JavaExtensionLibrary
Constructor Summary | |
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ExtensionFunctionCall()
Default constructor |
Method Summary | |
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void | checkArguments(StaticContext env)
Method called by the expression parser when all arguments have been supplied |
int | computeCardinality() |
protected Object | getField(Field field, Object instance)
Access a field. |
int | getIntrinsicDependencies()
Determine which aspects of the context the expression depends on. |
ItemType | getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible. |
Class | getTargetClass()
Get the class containing the method being called |
AccessibleObject | getTargetMethod()
Get the target method (or field, or constructor) being called |
void | init(int nameCode, Class theClass, AccessibleObject object, Configuration config)
Initialization: creates an ExtensionFunctionCall |
protected Object | invokeConstructor(Constructor constructor, Object[] params)
Invoke a constructor. |
protected Object | invokeMethod(Method method, Object instance, Object[] params)
Invoke a method. |
SequenceIterator | iterate(XPathContext context)
Evaluate the function. |
Expression | preEvaluate(StaticContext env)
preEvaluate: this method suppresses compile-time evaluation by doing nothing
(because the external function might have side-effects and might use the context) |
boolean | usesFocus()
Determine whether this method uses the focus. |
Parameters: field The field to be retrieved instance The object whose field is to be retrieved. This is set to null if the field is static.
Returns: The value of the field
Throws: IllegalAccessException if the invocation throws an IllegalAccessException
This method will always return a result, though it may be the best approximation that is available at the time.
Parameters: th
Returns: the item type
Parameters: nameCode the name code of the function, for display purposes theClass the Java class containing the method to be called object the method, field, or constructor of the Java class to be called
Parameters: constructor The constructor to be invoked params The parameters to be passed to the constructor
Returns: The object returned by the constructor
Throws: InstantiationException if the invocation throws an InstantiationException IllegalAccessException if the invocation throws an IllegalAccessException InvocationTargetException if the invocation throws an InvocationTargetException (which happens when the constructor itself throws an exception)
Parameters: method The method to be invoked instance The object on which the method is to be invoked. This is set to null if the method is static. params The parameters to be passed to the method
Returns: The object returned by the method
Throws: IllegalAccessException if the invocation throws an IllegalAccessException InvocationTargetException if the invocation throws an InvocationTargetException (which happens when the method itself throws an exception)
Parameters: context The context in which the function is to be evaluated
Returns: a Value representing the result of the function.
Throws: net.sf.saxon.trans.XPathException if the function cannot be evaluated.