com.luciad.util.collections

LuciadLightspeedInterface ILcdMultiKeyMap<K,V>

All Superinterfaces:

Map<K,V>

All Known Subinterfaces:

ILcdMultiKeyCache, ILspGLResourceCache

public interface ILcdMultiKeyMap<K,V>
extends Map<K,V>

Interface for a map that uses multiple keys per stored value. The multiple keys effectively change the map from a traditional key-value mapping to a tree structure. Each node in this tree structure is an ILspMultiKeyMap itself. As an example of why this is useful, it is common for painters to cache computed data which depends on the painter, on a domain object and on the view's current world reference. This interface supports this scenario by allowing all three of these objects to be used as the key for the stored value.

A more traditional single-key/single-value mapping could support this as well by using an array or composite of objects as the key. However, exposing the tree-like nature of the data structure allows for more efficient implementations. For example, to add multiple values to the same branch it is better to first retrieve the branch using the getBranch(Object[]) method and from then on work with the resulting branch. The below code snippets are equivalent, but the first is more efficient.

Variant 1:

 ILcdMultiKeyMap map;
 K key1, key2, key3, key4;
 V value1, value2;
 K[] keys = {key1, key2};
 ILcdMultiKeyMap branch = map.getOrCreateBranch(keys);
 branch.put(key3, value1 );
 branch.put(key4, value2 );
 

Variant 2:

 ILcdMultiKeyMap map;
 K key1, key2, key3, key4;
 V value1, value2;
 K[] keys1 = {key1, key2, key3};
 K[] keys2 = {key1, key2, key4};
 map.put(keys1, value1);
 map.put(keys2, value2);
 

The Map interface methods operate on the current node.

Since:

2012.0

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Method Summary

Modifier and Type	Method and Description
Set<? extends Map.Entry<K,? extends ILcdMultiKeyMap<K,V>>>	branchEntrySet() Gets the entries of this branch's branch map.
Set<K>	branchKeySet() Gets the keys associated with the branches of this map.
int	branchSize() Gets the number of branches.
Collection<? extends ILcdMultiKeyMap<K,V>>	branchValues() Gets the values of this branch's leaf map.
void	clearRecursive() Clears the entire contents of the multi-key map, not just the map at this level, but also the branches.
V	get(K[] aKeys) Returns the entry corresponding to the specified list of keys.
ILcdMultiKeyMap<K,V>	getBranch(K[] aKeys) Returns the branch that is associated with the given key, or null if the branch does not exist.
ILcdMultiKeyMap<K,V>	getOrCreateBranch(K[] aKeys) Creates and returns a new branch for the given key.
void	put(K[] aKeys, V aValue) Inserts a entry with the given keys and value.
Iterable<K[]>	recursiveLeafKeySet() Gets all keys in this map, recursively
void	remove(K[] aKeys) Removes all entries whose list of keys starts with the specified key sequence.
void	removeRecursive(K aKey) Removes all entries from the map whose list of keys contains the specified object.

Methods inherited from interface java.util.Map

clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

Method Detail

getBranch

ILcdMultiKeyMap<K,V> getBranch(K[] aKeys)

Returns the branch that is associated with the given key, or null if the branch does not exist.

Parameters:

aKeys - the key

Returns:

the branch associated with the given key, can be null if a branch does not exist.

See Also:

getOrCreateBranch(Object[])

getOrCreateBranch

ILcdMultiKeyMap<K,V> getOrCreateBranch(K[] aKeys)

Creates and returns a new branch for the given key. A new branch (or sub-branch) is only created when necessary.

Parameters:

aKeys - the key

Returns:

the branch associated with the given key. This method never returns null.

get

V get(K[] aKeys)

Returns the entry corresponding to the specified list of keys. If no match is found for the keys, this method returns null.

Parameters:

aKeys - the list of keys

Returns:

the resulting value, or null if no value is associated with the key sequence

put

void put(K[] aKeys,
         V aValue)

Inserts a entry with the given keys and value. If a mapping corresponding to the given keys already exists, it is overwritten.

Parameters:

aKeys - the list of keys

aValue - the value

remove

void remove(K[] aKeys)

Removes all entries whose list of keys starts with the specified key sequence.

Parameters:

aKeys - the list of keys

removeRecursive

void removeRecursive(K aKey)

Removes all entries from the map whose list of keys contains the specified object. The object can occur at any location in the key sequence; it does not have to be the first key.

Parameters:

aKey - the key

clearRecursive

void clearRecursive()

Clears the entire contents of the multi-key map, not just the map at this level, but also the branches.

branchSize

int branchSize()

Gets the number of branches.

Returns:

the number of child branches

branchKeySet

Set<K> branchKeySet()

Gets the keys associated with the branches of this map.

Returns:

the branches key set

recursiveLeafKeySet

Iterable<K[]> recursiveLeafKeySet()

Gets all keys in this map, recursively

Returns:

all the keys in this map

branchEntrySet

Set<? extends Map.Entry<K,? extends ILcdMultiKeyMap<K,V>>> branchEntrySet()

Gets the entries of this branch's branch map.

Returns:

the branch entry set

branchValues

Collection<? extends ILcdMultiKeyMap<K,V>> branchValues()

Gets the values of this branch's leaf map.

Returns:

the branch value set