net.sf.saxon.dotnet

Class DotNetExtensionFunctionCall

Implemented Interfaces:
EvaluableItem, InstructionInfoProvider, SequenceIterable, Serializable, SourceLocator

public class DotNetExtensionFunctionCall
extends FunctionCall

This class acts as a container for an extension function defined to call a method in a user-defined .NET class.

Note that the binding of an XPath function call to a .NET method is done in class DotNetExtensionLibrary

Field Summary

static cli.System.Type
CLI_ARRAYLIST
static cli.System.Type
CLI_BOOLEAN
static cli.System.Type
CLI_DECIMAL
static cli.System.Type
CLI_DOCUMENTINFO
static cli.System.Type
CLI_DOUBLE
static cli.System.Type
CLI_ICOLLECTION
static cli.System.Type
CLI_IENUMERABLE
static cli.System.Type
CLI_INT16
static cli.System.Type
CLI_INT32
static cli.System.Type
CLI_INT64
static cli.System.Type
CLI_ITEM
static cli.System.Type
CLI_NODEINFO
static cli.System.Type
CLI_OBJECT
static cli.System.Type
CLI_SEQUENCEITERATOR
static cli.System.Type
CLI_SINGLE
static cli.System.Type
CLI_STRING
static cli.System.Type
CLI_VALUE

Fields inherited from class net.sf.saxon.expr.FunctionCall

argument

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Constructor Summary

DotNetExtensionFunctionCall()
Default constructor

Method Summary

PathMap.PathMapNodeSet
addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
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
static Value
convertFromDotNet(Object result, cli.System.Type returnType, XPathContext context)
static Object
convertToDotNet(Value value, cli.System.Type targetType, XPathContext context)
Convert an XPath value to a .NET object
Expression
copy()
Copy an expression.
protected Object
getField(FieldInfo 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.
protected Object
getProperty(PropertyInfo property, Object instance)
Access a property.
cli.System.Type
getTargetClass()
Get the class containing the method being called
MemberInfo
getTargetMethod()
Get the target method (or field, property, or constructor) being called
void
init(StructuredQName functionName, cli.System.Type theClass, MemberInfo object, Configuration config)
Initialization: creates an ExtensionFunctionCall
protected Object
invokeConstructor(ConstructorInfo constructor, Object[] params)
Invoke a constructor.
protected Object
invokeMethod(MethodInfo method, Object instance, Object[] params)
Invoke a method.
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 cli.System.Type
type(java.lang.String name)

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

addExternalFunctionCallToPathMap, checkArgumentCount, checkArguments, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Field Details

CLI_ARRAYLIST

public static cli.System.Type CLI_ARRAYLIST

CLI_BOOLEAN

public static cli.System.Type CLI_BOOLEAN

CLI_DECIMAL

public static cli.System.Type CLI_DECIMAL

CLI_DOCUMENTINFO

public static cli.System.Type CLI_DOCUMENTINFO

CLI_DOUBLE

public static cli.System.Type CLI_DOUBLE

CLI_ICOLLECTION

public static cli.System.Type CLI_ICOLLECTION

CLI_IENUMERABLE

public static cli.System.Type CLI_IENUMERABLE

CLI_INT16

public static cli.System.Type CLI_INT16

CLI_INT32

public static cli.System.Type CLI_INT32

CLI_INT64

public static cli.System.Type CLI_INT64

CLI_ITEM

public static cli.System.Type CLI_ITEM

CLI_NODEINFO

public static cli.System.Type CLI_NODEINFO

CLI_OBJECT

public static cli.System.Type CLI_OBJECT

CLI_SEQUENCEITERATOR

public static cli.System.Type CLI_SEQUENCEITERATOR

CLI_SINGLE

public static cli.System.Type CLI_SINGLE

CLI_STRING

public static cli.System.Type CLI_STRING

CLI_VALUE

public static cli.System.Type CLI_VALUE

Constructor Details

DotNetExtensionFunctionCall

public DotNetExtensionFunctionCall()
Default constructor

Method Details

addToPathMap

public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

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.

Overrides:
addToPathMap in interface Expression
Parameters:
pathMap - the PathMap to which the expression should be added
pathMapNodeSet -
Returns:
the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

checkArguments

public void checkArguments(ExpressionVisitor visitor)
            throws XPathException
Method called by the expression parser when all arguments have been supplied
Overrides:
checkArguments in interface FunctionCall

computeCardinality

public int computeCardinality()
Compute the static cardinality of this expression
Overrides:
computeCardinality in interface Expression

convertFromDotNet

public static Value convertFromDotNet(Object result,
                                      cli.System.Type returnType,
                                      XPathContext context)

convertToDotNet

public static Object convertToDotNet(Value value,
                                     cli.System.Type targetType,
                                     XPathContext context)
            throws XPathException
Convert an XPath value to a .NET object
Parameters:
value - the XPath value to be converted
targetType - the target type of the .NET object
context - XPath dynamic context
Returns:
the .NET object
Throws:
XPathException -

copy

public Expression copy()
Copy an expression. This makes a deep copy.
Overrides:
copy in interface Expression
Returns:
the copy of the original expression

getField

protected Object getField(FieldInfo field,
                          Object instance)
            throws 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 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

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 interface Expression

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.

Overrides:
getItemType in interface Expression
Parameters:
th - type hierarchy cache
Returns:
the item type

getProperty

protected Object getProperty(PropertyInfo property,
                             Object instance)
            throws IllegalAccessException
Access a property. 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:
property - The property to be retrieved
instance - The object whose property is to be retrieved. This is set to null if the property is static.
Returns:
The value of the property

getTargetClass

public cli.System.Type getTargetClass()
Get the class containing the method being called
Returns:
the containing class

getTargetMethod

public MemberInfo getTargetMethod()
Get the target method (or field, property, or constructor) being called
Returns:
the target method

init

public void init(StructuredQName functionName,
                 cli.System.Type theClass,
                 MemberInfo object,
                 Configuration config)
Initialization: creates an ExtensionFunctionCall
Parameters:
functionName - the name of the function, for display purposes
theClass - the .NET class containing the method to be called
object - the method, field, or constructor of the .NET class to be called
config - the Saxon configuration

invokeConstructor

protected Object invokeConstructor(ConstructorInfo constructor,
                                   Object[] params)
            throws InstantiationException,
                   IllegalAccessException,
                   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 invoked
params - The parameters to be passed to the constructor
Returns:
The object returned by the constructor

invokeMethod

protected Object invokeMethod(MethodInfo method,
                              Object instance,
                              Object[] params)
            throws IllegalAccessException,
                   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 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

iterate

public SequenceIterator iterate(XPathContext context)
            throws XPathException
Evaluate the function.
Specified by:
iterate in interface SequenceIterable
Overrides:
iterate in interface Expression
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.

preEvaluate

public 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)
Overrides:
preEvaluate in interface FunctionCall
Parameters:
visitor - an expression visitor

type

public static cli.System.Type type(java.lang.String name)