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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.FunctionCall com.saxonica.expr.JavaExtensionFunctionCall
public class JavaExtensionFunctionCall
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
Nested Class Summary | |
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static class |
JavaExtensionFunctionCall.ConfigurationCheckingFunction
This class checks that NodeInfo objects returned by an extension function were created under the right Configuration |
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.Expression |
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EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
Constructor Summary | |
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JavaExtensionFunctionCall()
Default constructor |
Method Summary | |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
protected SequenceIterator |
call(ValueRepresentation[] argValues,
XPathContext context)
Call an extension function previously identified using the bind() method. |
void |
checkArguments(ExpressionVisitor visitor)
Method called by the expression parser when all arguments have been supplied |
int |
computeCardinality()
Compute the static cardinality of this expression |
Expression |
copy()
Copy an expression. |
PJConverter[] |
getArgumentConverters()
Get the converters used to convert the arguments from XPath values to Java values |
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[] |
getParameterTypes()
Get the types of the arguments |
JPConverter |
getResultConverter()
Get the converter used to convert the result from a Java object to an XPath value |
Class |
getReturnClass()
Get the Java class of the value returned by the method |
Class |
getTargetClass()
Get the class containing the method being called |
AccessibleObject |
getTargetMethod()
Get the target method (or field, or constructor) being called |
void |
init(StructuredQName functionName,
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. |
boolean |
isNodeCheckRequired()
Ask whether the result needs to be checked to ensure it contains no nodes from the wrong Configuration |
boolean |
isSubtreeExpression()
Determine whether the expression can be evaluated without reference to the part of the context document outside the subtree rooted at the context node. |
SequenceIterator |
iterate(XPathContext context)
Evaluate the function. |
Expression |
preEvaluate(ExpressionVisitor visitor)
preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the external function might have side-effects and might use the context) |
static String |
toCamelCase(String name,
boolean debug,
PrintStream diag)
Convert a name to camelCase (by removing hyphens and changing the following letter to capitals) |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression. |
Methods inherited from class net.sf.saxon.expr.FunctionCall |
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addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public JavaExtensionFunctionCall()
Method Detail |
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public void init(StructuredQName functionName, Class theClass, AccessibleObject object, Configuration config)
functionName
- the name 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 calledconfig
- the Saxon configurationpublic Expression preEvaluate(ExpressionVisitor visitor)
preEvaluate
in class FunctionCall
visitor
- an expression visitor
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
FunctionCall
typeCheck
in class FunctionCall
visitor
- an expression visitorcontextItemType
- the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public void checkArguments(ExpressionVisitor visitor) throws XPathException
checkArguments
in class FunctionCall
visitor
- the expression visitor
XPathException
- if the arguments are incorrectpublic Expression copy()
copy
in class Expression
public int getIntrinsicDependencies()
getIntrinsicDependencies
in class Expression
public boolean isSubtreeExpression()
isSubtreeExpression
in class Expression
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
addToPathMap
in class Expression
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the PathMapNodeSet to which the paths embodied in this expression should be added
public boolean isNodeCheckRequired()
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Expression
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 Class[] getParameterTypes()
protected SequenceIterator call(ValueRepresentation[] argValues, XPathContext context) throws XPathException
argValues
- The values of the argumentscontext
- The XPath dynamic evaluation context
XPathException
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.
getItemType
in class Expression
th
- the type hierarchy cache
public int computeCardinality()
Expression
computeCardinality
in class Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public Class getReturnClass()
public PJConverter[] getArgumentConverters()
public JPConverter getResultConverter()
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 IllegalAccessExceptionpublic static String toCamelCase(String name, boolean debug, PrintStream diag)
name
- the name to be converted to camelCasedebug
- true if tracing is requireddiag
- the output stream for diagnostic trace output
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