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:

java.util.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

java.util.Map.Entry<K extends java.lang.Object,V extends java.lang.Object>

Field Summary

Fields

Modifier and Type	Field	Description
protected IntSet	allowedSegments
protected ConsistentHash	ch
protected java.util.Map<K,V>	map
protected java.util.Set<java.util.Map.Entry<K,V>>	segmentAwareEntrySet
protected java.util.Set<K>	segmentAwareKeySet

Constructor Summary

Constructors

Constructor	Description
ReadOnlySegmentAwareMap(java.util.Map<K,V> map, ConsistentHash ch, IntSet allowedSegments)

Method Summary

Modifier and Type	Method	Description
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
protected java.util.Map<K,V>	delegate()
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
V	get(java.lang.Object key)
boolean	isEmpty()	Checks if the provided map is empty.
protected boolean	keyAllowed(java.lang.Object key)
java.util.Set<K>	keySet()
int	size()	Returns the size of the read only map.
java.lang.String	toString()
java.util.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 Detail

map

protected final java.util.Map<K,V> map

ch

protected final ConsistentHash ch

allowedSegments

protected final IntSet allowedSegments

segmentAwareKeySet

protected java.util.Set<K> segmentAwareKeySet

segmentAwareEntrySet

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

Constructor Detail

ReadOnlySegmentAwareMap

public ReadOnlySegmentAwareMap(java.util.Map<K,V> map,
                               ConsistentHash ch,
                               IntSet allowedSegments)

Method Detail

delegate

protected java.util.Map<K,V> delegate()

Specified by:

delegate in class AbstractDelegatingMap<K,V>

keyAllowed

protected boolean keyAllowed(java.lang.Object key)

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<K,V>

Overrides:

containsKey in class AbstractDelegatingMap<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,V>

Overrides:

containsValue in class AbstractDelegatingMap<K,V>

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V>

Overrides:

get in class AbstractDelegatingMap<K,V>

entrySet

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

Specified by:

entrySet in interface java.util.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 java.util.Map<K,V>

Overrides:

isEmpty in class AbstractDelegatingMap<K,V>

keySet

public java.util.Set<K> keySet()

Specified by:

keySet in interface java.util.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 ReadOnlySegmentAwareEntryMap#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 java.util.Map<K,V>

Overrides:

size in class AbstractDelegatingMap<K,V>

values

public java.util.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 java.util.Map<K,V>

Overrides:

values in class AbstractDelegatingMap<K,V>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object