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java.lang.Objectnet.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.ExtensionFunctionCall
This class acts as a container for an extension function defined to call a method in a user-defined class.
Note that the binding of an XPath function call to a Java method is done in
class JavaExtensionLibrary
Field Summary |
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Fields inherited from class net.sf.saxon.expr.FunctionCall |
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argument |
Fields inherited from class net.sf.saxon.expr.ComputedExpression |
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locationId, staticProperties |
Fields inherited from interface net.sf.saxon.expr.Expression |
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EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD |
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()
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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. |
Methods inherited from class net.sf.saxon.expr.FunctionCall |
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checkArgumentCount, display, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, promote, setArguments, setFunctionNameCode, simplify, simplifyArguments, typeCheck |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public ExtensionFunctionCall()
Method Detail |
public void init(int nameCode, Class theClass, AccessibleObject object, Configuration config)
nameCode
- the name code of the function, for display purposestheClass
- the Java class containing the method to be calledobject
- the method, field, or constructor of the Java class to be calledpublic Expression preEvaluate(StaticContext env)
preEvaluate
in class FunctionCall
public void checkArguments(StaticContext env) throws XPathException
checkArguments
in class FunctionCall
XPathException
public int getIntrinsicDependencies()
getIntrinsicDependencies
in class ComputedExpression
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- The context in which the function is to be evaluated
XPathException
- if the function cannot be evaluated.public Class getTargetClass()
public AccessibleObject getTargetMethod()
public ItemType getItemType(TypeHierarchy th)
This method will always return a result, though it may be the best approximation that is available at the time.
th
-
public int computeCardinality()
computeCardinality
in class ComputedExpression
public boolean usesFocus()
protected Object invokeConstructor(Constructor constructor, Object[] params) throws InstantiationException, IllegalAccessException, InvocationTargetException
constructor
- The constructor to be invokedparams
- The parameters to be passed to the constructor
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)protected Object invokeMethod(Method method, Object instance, Object[] params) throws IllegalAccessException, InvocationTargetException
method
- The method to be invokedinstance
- 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
IllegalAccessException
- if the invocation throws an IllegalAccessException
InvocationTargetException
- if the invocation throws an InvocationTargetException (which happens
when the method itself throws an exception)protected Object getField(Field field, Object instance) throws IllegalAccessException
field
- The field to be retrievedinstance
- The object whose field is to be retrieved. This is set to null if the
field is static.
IllegalAccessException
- if the invocation throws an IllegalAccessException
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