Google

: Class FunctionProxy
Overview  Package   Class  Tree  Deprecated  Index  Help 
 PREV CLASS   NEXT CLASS FRAMES    NO FRAMES
SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD

com.icl.saxon.expr
Class FunctionProxy


java.lang.Object

  |

  +--com.icl.saxon.expr.Expression

        |

        +--com.icl.saxon.expr.Function

              |

              +--com.icl.saxon.expr.FunctionProxy
public class FunctionProxy
extends Function

This class acts as a proxy for an extension function defined as a method in a user-defined class

Fields inherited from class com.icl.saxon.expr.Function
argument
 
Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
FunctionProxy()
          Constructor: creates an uncommitted FunctionProxy
 
Method Summary
static Value convertJavaObjectToXPath(java.lang.Object result, Controller controller)
          Convert a Java object to an XPath value.
 NodeEnumeration enumerate(Context context, boolean requireSorted)
          Return an enumeration of nodes in a nodeset.
 Value evaluate(Context context)
          Evaluate the function.
 boolean evaluateAsBoolean(Context context)
          Evaluate an expression as a Boolean.
The result of x.evaluateAsBoolean(c) must be equivalent to x.evaluate(c).asBoolean(); but optimisations are possible when it is known that a boolean result is required, especially in the case of a NodeSet.
 double evaluateAsNumber(Context context)
          Evaluate an expression as a Number.
The result of x.evaluateAsNumber(c) must be equivalent to x.evaluate(c).asNumber(); but optimisations are possible when it is known that a numeric result is required, especially in the case of a NodeSet.
 java.lang.String evaluateAsString(Context context)
          Evaluate an expression as a String.
The result of x.evaluateAsString(c) must be equivalent to x.evaluate(c).asString(); but optimisations are possible when it is known that a string result is required, especially in the case of a NodeSet.
 java.lang.Object getBestFit(Value[] argValues)
          Get the best fit amongst all the candidate methods or constructors
 int getDataType()
          Determine the data type of the expression, if possible
 int getDependencies()
          Determine which aspects of the context the expression depends on.
 java.lang.String getName()
          Get the name of the function
 Expression reduce(int dependencies, Context context)
          Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
 boolean setFunctionName(java.lang.Class reqClass, java.lang.String localName)
          setFunctionName: locates the external class and the method (or candidate methods) to which this function relates.
 Expression simplify()
          Simplify the function (by simplifying its arguments)
 
Methods inherited from class com.icl.saxon.expr.Function
addArgument, checkArgumentCount, display, getNumberOfArguments
 
Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsNodeSet, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FunctionProxy


public FunctionProxy()
Constructor: creates an uncommitted FunctionProxy
Method Detail

setFunctionName


public boolean setFunctionName(java.lang.Class reqClass,
                               java.lang.String localName)
setFunctionName: locates the external class and the method (or candidate methods) to which this function relates. At this stage addArguments() will have normally been called, so the number of arguments is known. If no method of the required name is located, an exception is saved, but it is not thrown until an attempt is made to evaluate the function. All methods that match the required number of arguments are saved in a list (candidateMethods), a decision among these methods is made at run-time when the types of the actual arguments are known.

The method is also used while calling function-available(). In this case the number of arguments is not known (it will be set to zero). We return true if a match was found, regardless of the number of arguments.

Parameters:
className - The Java class name
localName - The local name used in the XPath function call
Returns:
true if the function is available (with some number of arguments).

getDataType


public int getDataType()
Determine the data type of the expression, if possible
Overrides:
getDataType in class Expression
Returns:
Value.ANY (meaning not known in advance)

getName


public java.lang.String getName()
Get the name of the function
Overrides:
getName in class Function
Following copied from class: com.icl.saxon.expr.Function
Returns:
the name of the function, as used in XSL expressions, but excluding its namespace prefix

simplify


public Expression simplify()
                    throws XPathException
Simplify the function (by simplifying its arguments)
Overrides:
simplify in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Returns:
the simplified expression

getDependencies


public int getDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE
Overrides:
getDependencies in class Expression

reduce


public Expression reduce(int dependencies,
                         Context context)
                  throws XPathException
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Overrides:
reduce in class Expression
Parameters:
dependencies - The dependencies to be removed
context - The context to be used for the partial evaluation
Returns:
a new expression that does not have any of the specified dependencies

getBestFit


public java.lang.Object getBestFit(Value[] argValues)
                            throws XPathException
Get the best fit amongst all the candidate methods or constructors
Returns:
the result is either a Method or a Constructor. In JDK 1.2 these have a common superclass, AccessibleObject, but this is not available in JDK 1.1, which we still support.

evaluate


public Value evaluate(Context context)
               throws XPathException
Evaluate the function.
Overrides:
evaluate in class 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.

evaluateAsString


public java.lang.String evaluateAsString(Context context)
                                  throws XPathException
Description copied from class: Expression
Evaluate an expression as a String.
The result of x.evaluateAsString(c) must be equivalent to x.evaluate(c).asString(); but optimisations are possible when it is known that a string result is required, especially in the case of a NodeSet.
Overrides:
evaluateAsString in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context

evaluateAsNumber


public double evaluateAsNumber(Context context)
                        throws XPathException
Description copied from class: Expression
Evaluate an expression as a Number.
The result of x.evaluateAsNumber(c) must be equivalent to x.evaluate(c).asNumber(); but optimisations are possible when it is known that a numeric result is required, especially in the case of a NodeSet.
Overrides:
evaluateAsNumber in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context

evaluateAsBoolean


public boolean evaluateAsBoolean(Context context)
                          throws XPathException
Description copied from class: Expression
Evaluate an expression as a Boolean.
The result of x.evaluateAsBoolean(c) must be equivalent to x.evaluate(c).asBoolean(); but optimisations are possible when it is known that a boolean result is required, especially in the case of a NodeSet.
Overrides:
evaluateAsBoolean in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context

enumerate


public NodeEnumeration enumerate(Context context,
                                 boolean requireSorted)
                          throws XPathException
Description copied from class: Expression
Return an enumeration of nodes in a nodeset.
Overrides:
enumerate in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
sorted - Indicates whether the nodes are required in document order. If this is false, they may come in any order, but there will be no duplicates.
Throws:
XPathException - when the expression does not return a nodeset.

convertJavaObjectToXPath


public static Value convertJavaObjectToXPath(java.lang.Object result,
                                             Controller controller)
                                      throws XPathException
Convert a Java object to an XPath value. This method is called to handle the result of an external function call (but only if the required type is not known), and also to process global parameters passed to the stylesheet.
Overview  Package   Class  Tree  Deprecated  Index  Help 
 PREV CLASS   NEXT CLASS FRAMES    NO FRAMES
SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD