## Package net.sf.saxon.functions

This package provides implementations of all the core functions available for use in XPath expressions.

See:
Description

Interface Summary
ExtensionFunctionFactory: This is a marker interface representing an abstract superclass of JavaExtensionFunctionFactory and DotNetExtensionFunctionFactory.
FunctionLibrary: A FunctionLibrary handles the binding of function calls in XPath (or XQuery) expressions.
XSLTFunction: This is a marker interface used to identify functions that are defined in XSLT rather than in XPath

Class Summary
Adjust: This class implements the XPath 2.0 functions adjust-date-to-timezone(), adjust-time-timezone(), and adjust-dateTime-timezone().
Aggregate: This class implements the sum(), avg(), count() functions,
Available: This class supports the XSLT element-available and function-available functions.
BaseURI: This class supports the base-uri() functions in XPath 2.0
BooleanFn: This class supports the XPath functions boolean(), not(), true(), and false()
CodepointEqual: XPath 2.0 codepoint-equal() function.
CodepointsToString: This class supports the function codepoints-to-string
CollatingFunction: Abstract superclass for all functions that take an optional collation argument
Collection: Implement the fn:collection() function.
Compare: XSLT 2.0 compare() function
CompileTimeFunction: Abtract class representing a function call that is always rewritten at compile-time: it can never be executed
Component: This class supports the get_X_from_Y functions defined in XPath 2.0
Concat
ConstructorFunctionLibrary: The ConstructorFunctionLibrary represents the collection of constructor functions for atomic types.
Contains: This class implements the contains(), starts-with(), ends-with(), substring-before(), and substring-after() functions
Current: Implement the XSLT current() function
CurrentDateTime: This class implements the XPath 2.0 functions current-date(), current-time(), and current-dateTime(), as well as the function implicit-timezone().
CurrentGroup: Implements the XSLT functions current-group() and current-grouping-key()
Data: Implement XPath function fn:data()
DateTimeConstructor: This class supports the dateTime($date, $time) function
DeepEqual: XSLT 2.0 deep-equal() function.
DefaultCollation: Implement the XPath 2.0 default-collation() function
DistinctValues: The XPath 2.0 distinct-values() function
DistinctValues.DistinctIterator: Iterator class to return the distinct values in a sequence
Doc: Implement the fn:doc() function - a simplified form of the Document function
DocAvailable: Implement the fn:doc-available() function
Document: Implements the XSLT document() function
Error: Implement XPath function fn:error()
EscapeURI: This class supports the functions encode-for-uri() and iri-to-uri()
Evaluate: This class implements the saxon:evaluate(), saxon:expression(), and saxon:eval() extension functions, which are specially-recognized by the system because they need access to parts of the static context
Evaluate.PreparedExpression: Inner class PreparedExpression represents a compiled XPath expression together with the standard variables $p1 ..
ExecutableFunctionLibrary: An ExecutableFunctionLibrary is a function library that contains definitions of functions for use at run-time.
Existence: Implement the exists() and empty() functions
ExtensionFunctionCall: This class acts as a container for an extension function defined to call a method in a user-defined class.
Extensions: This class implements functions that are supplied as standard with SAXON, but which are not defined in the XSLT or XPath specifications.
ForceCase: This class implements the upper-case() and lower-case() functions
FormatDate: Implement the format-date() function in XPath 2.0
FormatNumber2: XSLT 2.0 implementation of format-number() function - removes the dependence on the JDK.
FunctionLibraryList: A FunctionLibraryList is a list of FunctionLibraries.
Id: The XPath id() function XPath 2.0 version: accepts any sequence as the first parameter; each item in the sequence is taken as an IDREFS value, that is, a space-separated list of ID values.
Idref
IndexOf: The XPath 2.0 index-of() function
IndexOf.IndexIterator: Iterator to return the index positions of selected items in a sequence
InScopePrefixes: This class supports fuctions get-in-scope-prefixes()
Insert: The XPath 2.0 insert-before() function
Insert.InsertIterator
JavaExtensionFunctionFactory: This class acts as a factory for creating expressions that call Java extension functions.
JavaExtensionLibrary: The JavaExtensionLibrary is a FunctionLibrary that binds XPath function calls to calls on Java methods (or constructors, or fields).
KeyFn
Lang
Last: Implement the XPath 1.0 function last()
Matches: This class implements the matches() function for regular expression matching
Minimax: This class implements the min() and max() functions
NamePart: This class supports the name(), local-name(), and namespace-uri() functions from XPath 1.0, and also the XSLT generate-id() function
NamespaceForPrefix: This class supports the function namespace-uri-for-prefix()
Nilled: This class supports the nilled() function
NormalizeSpace: Implement the XPath normalize-space() function
NormalizeUnicode: Implement the XPath normalize-unicode() function
NumberFn: Implements the XPath number() function.
Parse: This class implements the saxon:parse() extension function, which is specially-recognized by the system because it needs access to parts of the static context
Position
QNameFn: This class supports the fn:QName() function (previously named fn:expanded-QName())
RegexGroup
Remove: The XPath 2.0 remove() function
Remove.RemoveIterator: An implementation of SequenceIterator that returns all items except the one at a specified position.
Replace: This class implements the replace() function for replacing substrings that match a regular expression
ResolveQName: This class supports the resolve-QName function in XPath 2.0
ResolveURI: This class supports the resolve-uri() functions in XPath 2.0
Reverse: Implement XPath function fn:reverse()
Root: Implement the XPath 2.0 root() function
Rounding: This class supports the ceiling(), floor(), round(), and round-to-half-even() functions, and also the abs() function
Serialize: This class implements the saxon:serialize() extension function, which is specially-recognized by the system because it needs access to parts of the static context
StandardCollectionURIResolver: This class implements the default collection URI Resolver.
StandardFunction: This class contains static data tables defining the properties of standard functions.
StandardFunction.Entry: An entry in the table describing the properties of a function
StaticBaseURI: This class supports the static-base-uri() function in XPath 2.0 (added by the working groups on 24 August 2004)
StringFn: Implement XPath function string()
StringJoin: xf:string-join(string* $sequence, string $separator)
StringLength: Implement the XPath string-length() function
StringToCodepoints: This class supports the function string-to-codepoints()
Subsequence: Implements the XPath 2.0 subsequence() function
Substring: This class implements the XPath substring() function
SystemFunction: Abstract superclass for system-defined and user-defined functions
SystemFunctionLibrary: The SystemFunctionLibrary represents the collection of functions in the fn: namespace.
SystemProperty
Tokenize: This class implements the tokenize() function for regular expression matching.
Trace: This class supports the XPath 2.0 function trace().
Translate: Implement the XPath translate() function
TreatFn: This class supports the XPath 2.0 functions exactly-one(), one-or-more(), zero-or-one().
Unordered: XPath 2.0 unordered() function
UnparsedEntity: Implements the unparsed-entity-uri() function defined in XSLT 1.0 and the unparsed-entity-public-id() function defined in XSLT 2.0
UnparsedText
URIQueryParameters: A set of query parameters on a URI passed to the collection() or document() function
URIQueryParameters.RegexFilter
VendorFunctionLibrary: The VendorFunctionLibrary represents specially-recognized functions in the Saxon namespace.

## Package net.sf.saxon.functions Description

This package provides implementations of all the core functions available for use in XPath expressions. This includes all the functions defined in the XPath 2.0 Functions and Operators specification, as well as the additional functions defined for use in XSLT. The package also includes Saxon extension functions. Most of these are in a single class `Extensions`, but some of the more complex functions are in their own classes, for example `Evaluate` implements `saxon:evaluate()`.

There is one class for group of closely-related functions. These all inherit from the class net.sf.saxon.expr.Function. The class `StandardFunction` is used to map a function name to its implementation; it contains tables of information describing the signature of each function, so that the type-checking code is completely generic.

The package also contains machinery for defining user extension functions. A collection of functions is represented by a `FunctionLibrary` object. There are several standard function libraries available, covering core functions, Saxon extension functions constructor functions, and user extension functions: each category is covered by a subclass of `FunctionLibrary`, and there is also a `FunctionLibraryList` that represents the total collection of functions in these individual libraries. The `JavaExtensionLibrary` contains the logic for binding Java extension functions given their name and arity and the types of their arguments. The class `ExtensionFunctionCall` contains the run-time logic for converting XPath values to the required Java types, and for converting the result back to an XPath value.

These classes, although public, will not normally be used directly by user-written Java applications.

Michael H. Kay
Saxonica Limited
9 February 2005

Copyright (C) Michael H. Kay. All rights reserved.