Package net.sf.saxon.ma.map

Class MapFunctionSet.MapMerge

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.ma.map.MapFunctionSet.MapMerge

All Implemented Interfaces:

Callable, FunctionItem, GroundedValue, Item, Sequence

Enclosing class:

MapFunctionSet

public static class MapFunctionSet.MapMerge
extends SystemFunction

Implementation of the function map:merge() => Map From 9.8, map:merge is also used to implement map constructors in XPath and the xsl:map instruction in XSLT. For this purpose it accepts an additional option to define the error code to be used to signal duplicates.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	errorCodeKey
static final String	finalKey
static final String	keyTypeKey
static final String	onDuplicatesKey

Constructor Summary

Constructors

Constructor	Description
MapMerge()

Method Summary

Modifier and Type	Method	Description
MapItem	call(XPathContext context, Sequence[] arguments)	Call the Callable.
void	exportAdditionalArguments(SystemFunctionCall call, ExpressionPresenter out)	Export any implicit arguments held in optimized form within the SystemFunction call
ItemType	getResultItemType(Expression[] args)	Get the return type, given knowledge of the actual arguments
String	getStreamerName()	Get a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser.
Expression	makeOptimizedFunctionCall(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo, Expression... arguments)	Allow the function to create an optimized call based on the values of the actual arguments
static MapItem	mergeMaps(SequenceIterator iter, XPathContext context, String duplicates, String duplicatesErrorCode, FunctionItem onDuplicates)	Merge a sequence of maps into a single map

Methods inherited from class net.sf.saxon.functions.SystemFunction

dependsOnContextItem, dynamicCall, equals, export, exportAttributes, fixArguments, getArity, getCardinality, getContextNode, getDescription, getDetails, getElaborator, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, getUniStringArg, hashCode, importAttributes, isSequenceVariadic, isTrustedResultType, makeCall, makeFunction, makeFunction40, makeFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, toShortString, toString, typeCheckCaller

Methods inherited from class net.sf.saxon.functions.AbstractFunction

atomize, deepEqual40, deepEquals, effectiveBooleanValue, getAnnotations, getUnicodeStringValue, isArray, isMap, makeNewContext, simplify, typeCheck

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.FunctionItem

getGenre

Methods inherited from interface net.sf.saxon.om.GroundedValue

asIterable, concatenate, containsNode, materialize

Methods inherited from interface net.sf.saxon.om.Item

getLength, getStringValue, head, isStreamed, itemAt, iterate, reduce, subsequence

Methods inherited from interface net.sf.saxon.om.Sequence

makeRepeatable

Field Details

finalKey

public static final String finalKey

See Also:

• Constant Field Values

keyTypeKey

public static final String keyTypeKey

See Also:

• Constant Field Values

onDuplicatesKey

public static final String onDuplicatesKey

See Also:

• Constant Field Values

errorCodeKey

public static final String errorCodeKey

See Also:

• Constant Field Values

Constructor Details

MapMerge

public MapMerge()

Method Details

makeOptimizedFunctionCall

public Expression makeOptimizedFunctionCall(ExpressionVisitor visitor,
 ContextItemStaticInfo contextInfo,
 Expression... arguments)
                                     throws XPathException

Allow the function to create an optimized call based on the values of the actual arguments

Overrides:

makeOptimizedFunctionCall in class SystemFunction

Parameters:

visitor - the expression visitor

contextInfo - information about the context item

arguments - the supplied arguments to the function call. Note: modifying the contents of this array should not be attempted, it is likely to have no effect.

Returns:

either a function call on this function, or an expression that delivers the same result, or null indicating that no optimization has taken place

Throws:

XPathException - if an error is detected

getResultItemType

public ItemType getResultItemType(Expression[] args)

Get the return type, given knowledge of the actual arguments

Overrides:

getResultItemType in class SystemFunction

Parameters:

args - the actual arguments supplied

Returns:

the best available item type that the function will return

call

public MapItem call(XPathContext context,
 Sequence[] arguments)
             throws XPathException

Description copied from interface: Callable

Call the Callable.

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as Sequences.

Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

Returns:

the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

mergeMaps

public static MapItem mergeMaps(SequenceIterator iter,
 XPathContext context,
 String duplicates,
 String duplicatesErrorCode,
 FunctionItem onDuplicates)
                         throws XPathException

Merge a sequence of maps into a single map

Parameters:

iter - iterator over the input maps

context - The XPath dynamic context

duplicates - action to be taken when duplicate keys are encountered

duplicatesErrorCode - if duplicates are not allowed, the error code to be used

onDuplicates - callback to be used when duplicates = "use-callback"

Returns:

the merged map

Throws:

XPathException - if any error occurs, including detection of disallowed duplicates

getStreamerName

public String getStreamerName()

Description copied from class: SystemFunction

Get a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser. Special streaming support is generally available in Saxon-EE for all system functions that take a sequence as their argument.

Overrides:

getStreamerName in class SystemFunction

Returns:

a name that identifies a class that supports streamed evaluation of this system function, or null if no such class is available. The mapping of names to classes is defined in the Saxon-EE class StreamerMap. In non-streaming Saxon editions (HE and PE) the method always returns null.

exportAdditionalArguments

public void exportAdditionalArguments(SystemFunctionCall call,
 ExpressionPresenter out)
                               throws XPathException

Export any implicit arguments held in optimized form within the SystemFunction call

Overrides:

exportAdditionalArguments in class SystemFunction

Parameters:

call - the system function call (on this function)

out - the export destination

Throws:

XPathException - if a failure occurs (such as an I/O error)