Class CharacteristicTypeMap

java.lang.Object

org.apache.sis.internal.util.AbstractMap<String, DefaultAttributeType<?>>

org.apache.sis.feature.CharacteristicTypeMap

All Implemented Interfaces:

Map<String, DefaultAttributeType<?>>

final class CharacteristicTypeMap
extends AbstractMap<String, DefaultAttributeType<?>>

Implementation of the map returned by DefaultAttributeType.characteristics(). Information provided by this implementation are also used by CharacteristicMap.

Comparison with standard hash map

The straightforward approach would be to store the attributes directly as values in a standard HashMap. But instead of that, we store attributes in an array and the array indices in a HashMap. This level of indirection is useless if we consider only the DefaultAttributeType.characteristics() method, since a standard HashMap<String,AttributeType> would work as well or better. However, this level of indirection become useful for CharacteristicMap (the map returned by AbstractAttribute.characteristics()), since it allows a more efficient storage. We do this effort because some applications may create a very large amount of attribute instances.

Since:

0.5

Version:

0.8

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMap

AbstractMap.EntryIterator<K,V>, AbstractMap.IteratorAdapter<K,V>, AbstractMap.KeyIterator

Nested classes/interfaces inherited from interface Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
(package private) final DefaultAttributeType<?>[]	characterizedBy	Characteristics of another attribute type (the source attribute given to the constructor).
(package private) final Map<String,Integer>	indices	The names of attribute types listed in the characterizedBy array, together where their index in the array.
private static final WeakValueHashMap<DefaultAttributeType<?>[], CharacteristicTypeMap>	SHARED	For sharing the same CharacteristicTypeMap instances among the attribute types having the same characteristics.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	CharacteristicTypeMap(DefaultAttributeType<?> source, DefaultAttributeType<?>[] characterizedBy)	Creates a new map for the given attribute characteristics.

Method Summary

Modifier and Type	Method	Description
boolean	containsKey(Object key)	Returns true if this map contains an attribute characteristic of the given name.
boolean	containsValue(Object key)	Returns true if this map contains the given attribute characteristic.
(package private) static CharacteristicTypeMap	create(DefaultAttributeType<?> source, DefaultAttributeType<?>[] characterizedBy)	Creates a new map or return an existing map for the given attribute characteristics.
protected AbstractMap.EntryIterator<String, DefaultAttributeType<?>>	entryIterator()	Returns an iterator over the entries.
DefaultAttributeType<?>	get(Object key)	Returns the attribute characteristic for the given name, or null if none.
boolean	isEmpty()	Returns true if there are no attribute characteristics.
int	size()	Returns the number of attribute characteristics.

Methods inherited from class AbstractMap

addKey, addValue, clear, entrySet, equals, getOrDefault, hashCode, keySet, put, putAll, remove, toString, values

Methods inherited from class Object

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

Methods inherited from interface Map

compute, computeIfAbsent, computeIfPresent, forEach, merge, putIfAbsent, remove, replace, replace, replaceAll

Field Details

SHARED

private static final WeakValueHashMap<DefaultAttributeType<?>[], CharacteristicTypeMap> SHARED

For sharing the same CharacteristicTypeMap instances among the attribute types having the same characteristics.

characterizedBy

final DefaultAttributeType<?>[] characterizedBy

Characteristics of another attribute type (the source attribute given to the constructor). This array shall not be modified.

indices

final Map<String,Integer> indices

The names of attribute types listed in the characterizedBy array, together where their index in the array. This map shall not be modified.

Constructor Details

CharacteristicTypeMap

private CharacteristicTypeMap(DefaultAttributeType<?> source,
 DefaultAttributeType<?>[] characterizedBy)

Creates a new map for the given attribute characteristics.

This constructor does not clone the characterizedBy array. If that array is a user-provided argument, then cloning that array is caller responsibility.

Parameters:

source - the attribute which is characterized by characterizedBy.

characterizedBy - characteristics of source. Should not be empty.

Throws:

IllegalArgumentException - if two characteristics have the same name.

Method Details

create

static CharacteristicTypeMap create(DefaultAttributeType<?> source,
 DefaultAttributeType<?>[] characterizedBy)

Creates a new map or return an existing map for the given attribute characteristics.

This method does not clone the characterizedBy array. If that array is a user-provided argument, then cloning that array is caller responsibility.

Parameters:

source - the attribute which is characterized by characterizedBy.

characterizedBy - characteristics of source. Should not be empty.

Returns:

a map for this given characteristics.

Throws:

IllegalArgumentException - if two characteristics have the same name.

isEmpty

public boolean isEmpty()

Returns true if there are no attribute characteristics.

Specified by:

isEmpty in interface Map<String, DefaultAttributeType<?>>

Overrides:

isEmpty in class AbstractMap<String, DefaultAttributeType<?>>

Returns:

true if this map contains no element.

size

public int size()

Returns the number of attribute characteristics.

Specified by:

size in interface Map<String, DefaultAttributeType<?>>

Overrides:

size in class AbstractMap<String, DefaultAttributeType<?>>

containsKey

public boolean containsKey(Object key)

Returns true if this map contains an attribute characteristic of the given name.

Specified by:

containsKey in interface Map<String, DefaultAttributeType<?>>

Overrides:

containsKey in class AbstractMap<String, DefaultAttributeType<?>>

Parameters:

key - the key for which to test the presence of a value.

Returns:

true if the map contains a non-null value for the given key.

containsValue

public boolean containsValue(Object key)

Returns true if this map contains the given attribute characteristic.

Specified by:

containsValue in interface Map<String, DefaultAttributeType<?>>

Overrides:

containsValue in class AbstractMap<String, DefaultAttributeType<?>>

Parameters:

key - the value for which to test the presence.

Returns:

true if the map contains the given value.

get

public DefaultAttributeType<?> get(Object key)

Returns the attribute characteristic for the given name, or null if none.

entryIterator

protected AbstractMap.EntryIterator<String, DefaultAttributeType<?>> entryIterator()

Returns an iterator over the entries. This is not the iterator returned by public API like Map.entrySet().iterator().

Specified by:

entryIterator in class AbstractMap<String, DefaultAttributeType<?>>

Returns:

an iterator over the entries in this map, or null.