Package net.sf.saxon.ma.map

Class FixedMap

java.lang.Object

net.sf.saxon.ma.MapOrArray

net.sf.saxon.ma.map.MapItem

net.sf.saxon.ma.map.MapWithTypeCache

net.sf.saxon.ma.map.AbstractFixedMap

net.sf.saxon.ma.map.FixedMap

All Implemented Interfaces:

Iterable<KeyValuePair>, Callable, FunctionItem, GroundedValue, Item, Sequence

public class FixedMap
extends AbstractFixedMap

A general-purpose XDM map implementation that is ordered, that holds any kind of key, and that supports incremental modification only by copying the whole map to a different structure.

The implementation is based on an array of keys, an array of corresponding values, and a mutable Java java.util.HashMap (but encapsulated so no mutation can take place after the map has been built) that maps atomic match keys to integer positions in the array. If put or remove operations are subsequently attempted, the map is copied to a different implementation structure that supports functional modification.

The underlying implementation uses an instance of HashMap<AtomicMatchKey, KeyValuePair> For many data types this means that the key is held twice, once as the key, and once as part of the value. The reason for this is that the keys() function needs to return the original keys as supplied, complete with type annotation, which would not (always) have the same equality semantics. The AtomicMatchKey is computed from the actual key and in some cases is simply a wrapper with a different equals() method.

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.ma.map.MapItem

MapItem.KeyIterator

Field Summary

Fields inherited from class net.sf.saxon.ma.map.AbstractFixedMap

index, values

Fields inherited from class net.sf.saxon.ma.map.MapWithTypeCache

knownKeyType, knownValueType

Fields inherited from class net.sf.saxon.ma.map.MapItem

mapConstructorDuplicatesAction, xslMapDuplicatesAction, xslRecordDuplicatesAction

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	FixedMap(AtomicValue[] keys, GroundedValue[] values, HashMap<AtomicMatchKey,Integer> index, int specVersion)	Construct a FixedMap supplying the entries as an array of keys and a corresponding array of value.

Method Summary

Modifier and Type	Method	Description
protected AtomicValue	getKey(int position)	Get the key at a given offset.

Methods inherited from class net.sf.saxon.ma.map.AbstractFixedMap

ensureIndexed, get, getBuilder, getOffset, getPosition, getValue, iterator, keyValuePairs, put, putOffsetIfAbsent, remove, size, toString

Methods inherited from class net.sf.saxon.ma.map.MapWithTypeCache

conforms, setKnownType

Methods inherited from class net.sf.saxon.ma.map.MapItem

atomize, call, deepEqual40, deepEquals, effectiveBooleanValue, entries, export, followingKeyValuePairs, getAnnotations, getArity, getDescription, getFunctionItemType, getFunctionName, getGenre, getItemType, getItemTypeOfSequence, getOperandRoles, getSpecVersion, getTypedValue, getU, getUnicodeStringValue, getWithPlan, isArray, isEmpty, isKnownToConform, isMap, isTrustedResultType, itemAt, keys, makeNewContext, mapToString, precedingKeyValuePairs, setSpecVersion, toShortString

Methods inherited from class net.sf.saxon.ma.MapOrArray

obtainRootJNode

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

isSequenceVariadic

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

asIterable, concatenate, containsNode, materialize

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

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

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

makeRepeatable

Constructor Details

FixedMap

protected FixedMap(AtomicValue[] keys,
 GroundedValue[] values,
 HashMap<AtomicMatchKey,Integer> index,
 int specVersion)

Construct a FixedMap supplying the entries as an array of keys and a corresponding array of value. The caller is responsible for ensuring that there are no duplicate keys. The two arrays (of keys and values) must have the same length. The content of the arrays must not be subsequently modified.

Parameters:

keys - an array of keys

values - a corresponding array of values

index - a hash map indexing the values

Method Details

getKey

protected AtomicValue getKey(int position)

Description copied from class: AbstractFixedMap

Get the key at a given offset. This method is provided for use by subclasses, which can store the actual key in different ways.

Specified by:

getKey in class AbstractFixedMap

Parameters:

position - the offset (sibling position within the ordered map) of the required key

Returns:

the key at the specified position