Package net.sf.saxon.functions
Class ExtensionFunctionCall
- java.lang.Object
-
- net.sf.saxon.expr.ComputedExpression
-
- net.sf.saxon.expr.FunctionCall
-
- net.sf.saxon.functions.ExtensionFunctionCall
-
- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
public class ExtensionFunctionCall extends FunctionCall
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
- See Also:
- Serialized Form
-
-
Field Summary
-
Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
-
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
-
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
-
-
Constructor Summary
Constructors Constructor Description ExtensionFunctionCall()
Default constructor
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
checkArguments(StaticContext env)
Method called by the expression parser when all arguments have been suppliedint
computeCardinality()
protected java.lang.Object
getField(java.lang.reflect.Field field, java.lang.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.java.lang.Class
getTargetClass()
Get the class containing the method being calledjava.lang.reflect.AccessibleObject
getTargetMethod()
Get the target method (or field, or constructor) being calledvoid
init(int nameCode, java.lang.Class theClass, java.lang.reflect.AccessibleObject object, Configuration config)
Initialization: creates an ExtensionFunctionCallprotected java.lang.Object
invokeConstructor(java.lang.reflect.Constructor constructor, java.lang.Object[] params)
Invoke a constructor.protected java.lang.Object
invokeMethod(java.lang.reflect.Method method, java.lang.Object instance, java.lang.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
checkArgumentCount, display, getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplify, simplifyArguments, typeCheck
-
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
-
-
-
-
Method Detail
-
init
public void init(int nameCode, java.lang.Class theClass, java.lang.reflect.AccessibleObject object, Configuration config)
Initialization: creates an ExtensionFunctionCall- Parameters:
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 called
-
preEvaluate
public 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)- Overrides:
preEvaluate
in classFunctionCall
-
checkArguments
public void checkArguments(StaticContext env) throws XPathException
Method called by the expression parser when all arguments have been supplied- Specified by:
checkArguments
in classFunctionCall
- Throws:
XPathException
-
getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE- Overrides:
getIntrinsicDependencies
in classComputedExpression
- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
-
iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Evaluate the function.- Specified by:
iterate
in interfaceExpression
- Overrides:
iterate
in classComputedExpression
- Parameters:
context
- The context in which the function is to be evaluated- Returns:
- a Value representing the result of the function.
- Throws:
XPathException
- if the function cannot be evaluated.
-
getTargetClass
public java.lang.Class getTargetClass()
Get the class containing the method being called
-
getTargetMethod
public java.lang.reflect.AccessibleObject getTargetMethod()
Get the target method (or field, or constructor) being called
-
getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible. All expressions return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.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
-
computeCardinality
public int computeCardinality()
- Specified by:
computeCardinality
in classComputedExpression
-
usesFocus
public boolean usesFocus()
Determine whether this method uses the focus. True if the first argument is of type XPathContext.
-
invokeConstructor
protected java.lang.Object invokeConstructor(java.lang.reflect.Constructor constructor, java.lang.Object[] params) throws java.lang.InstantiationException, java.lang.IllegalAccessException, java.lang.reflect.InvocationTargetException
Invoke a constructor. This method is provided separately so that it can be refined in a subclass. For example, a subclass might perform tracing of calls, or might trap exceptions.- Parameters:
constructor
- The constructor to be invokedparams
- The parameters to be passed to the constructor- Returns:
- The object returned by the constructor
- Throws:
java.lang.InstantiationException
- if the invocation throws an InstantiationExceptionjava.lang.IllegalAccessException
- if the invocation throws an IllegalAccessExceptionjava.lang.reflect.InvocationTargetException
- if the invocation throws an InvocationTargetException (which happens when the constructor itself throws an exception)
-
invokeMethod
protected java.lang.Object invokeMethod(java.lang.reflect.Method method, java.lang.Object instance, java.lang.Object[] params) throws java.lang.IllegalAccessException, java.lang.reflect.InvocationTargetException
Invoke a method. This method is provided separately so that it can be refined in a subclass. For example, a subclass might perform tracing of calls, or might trap exceptions.- Parameters:
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- Returns:
- The object returned by the method
- Throws:
java.lang.IllegalAccessException
- if the invocation throws an IllegalAccessExceptionjava.lang.reflect.InvocationTargetException
- if the invocation throws an InvocationTargetException (which happens when the method itself throws an exception)
-
getField
protected java.lang.Object getField(java.lang.reflect.Field field, java.lang.Object instance) throws java.lang.IllegalAccessException
Access a field. This method is provided separately so that it can be refined in a subclass. For example, a subclass might perform tracing of calls, or might trap exceptions.- Parameters:
field
- The field to be retrievedinstance
- 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:
java.lang.IllegalAccessException
- if the invocation throws an IllegalAccessException
-
-