Package org.infinispan.distribution.util

Class ReadOnlySegmentAwareMap<K,V>

java.lang.Object

org.infinispan.commons.util.AbstractDelegatingMap<K,V>

org.infinispan.distribution.util.ReadOnlySegmentAwareMap<K,V>

All Implemented Interfaces:

Map<K,V>

public class ReadOnlySegmentAwareMap<K,V>
extends AbstractDelegatingMap<K,V>

Map implementation that shows a read only view of the provided entry by only allowing entries whose key maps to a given segment using the provided consistent hash.

Any operation that would modify this map will throw an UnsupportedOperationException

This map is useful when you don't want to copy an entire map but only need to see entries from the given segments.

Note many operations are not constant time when using this map. The values() method is not supported as well. Please check\ the method you are using to see if it will perform differently than normally expected.

Since:

7.2

Author:

wburns

Nested Class Summary

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

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
protected final IntSet	allowedSegments
protected final Map<K,V>	map
protected Set<Map.Entry<K,V>>	segmentAwareEntrySet
protected Set<K>	segmentAwareKeySet
protected final LocalizedCacheTopology	topology

Constructor Summary

Constructors

Constructor	Description
ReadOnlySegmentAwareMap(Map<K,V> map, LocalizedCacheTopology topology, IntSet allowedSegments)

Method Summary

Modifier and Type	Method	Description
boolean	containsKey(Object key)
boolean	containsValue(Object value)
protected Map<K,V>	delegate()
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
boolean	isEmpty()	Checks if the provided map is empty.
protected boolean	keyAllowed(Object key)
Set<K>	keySet()
int	size()	Returns the size of the read only map.
String	toString()
Collection<V>	values()	NOTE: this method is not supported.

Methods inherited from class org.infinispan.commons.util.AbstractDelegatingMap

clear, compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

equals, hashCode

Field Details

map

protected final Map<K,V> map

topology

protected final LocalizedCacheTopology topology

allowedSegments

protected final IntSet allowedSegments

segmentAwareKeySet

protected Set<K> segmentAwareKeySet

segmentAwareEntrySet

protected Set<Map.Entry<K,V>> segmentAwareEntrySet

Constructor Details

ReadOnlySegmentAwareMap

public ReadOnlySegmentAwareMap(Map<K,V> map,
 LocalizedCacheTopology topology,
 IntSet allowedSegments)

Method Details

delegate

protected Map<K,V> delegate()

Specified by:

delegate in class AbstractDelegatingMap<K,V>

keyAllowed

protected boolean keyAllowed(Object key)

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractDelegatingMap<K,V>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

Overrides:

containsValue in class AbstractDelegatingMap<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

Overrides:

get in class AbstractDelegatingMap<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

Overrides:

entrySet in class AbstractDelegatingMap<K,V>

isEmpty

public boolean isEmpty()

Checks if the provided map is empty. This is done by iterating over all of the keys until it can find a key that maps to a given segment.

This method should always be preferred over checking the size to see if it is empty.

This time complexity for this method between O(1) to O(N).

Specified by:

isEmpty in interface Map<K,V>

Overrides:

isEmpty in class AbstractDelegatingMap<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

Overrides:

keySet in class AbstractDelegatingMap<K,V>

size

public int size()

Returns the size of the read only map. This is done by iterating over all of the keys counting all that are in the segments.

If you are using this method to verify if the map is empty, you should instead use the isEmpty() as it will perform better if the size is only used for this purpose.

This time complexity for this method is always O(N).

Specified by:

size in interface Map<K,V>

Overrides:

size in class AbstractDelegatingMap<K,V>

values

public Collection<V> values()

NOTE: this method is not supported. Due to the nature of this map, we don't want to copy the underlying value collection. Thus almost any operation will require O(N) and therefore this method is not provided.

Specified by:

values in interface Map<K,V>

Overrides:

values in class AbstractDelegatingMap<K,V>

toString

public String toString()

Overrides:

toString in class Object