Package org.apache.catalina.tribes.tipis
Class LazyReplicatedMap<K,V>
- java.lang.Object
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- org.apache.catalina.tribes.tipis.AbstractReplicatedMap<K,V>
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- org.apache.catalina.tribes.tipis.LazyReplicatedMap<K,V>
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- Type Parameters:
K- The type of KeyV- The type of Value
- All Implemented Interfaces:
Serializable,Map<K,V>,ChannelListener,RpcCallback,Heartbeat,MembershipListener
public class LazyReplicatedMap<K,V> extends AbstractReplicatedMap<K,V>
A smart implementation of a stateful replicated map. uses primary/secondary backup strategy. One node is always the primary and one node is always the backup. This map is synchronized across a cluster, and only has one backup member.
A perfect usage for this map would be a session map for a session manager in a clustered environment.
The only way to modify this list is to use theput, putAll, removemethods. entrySet, entrySetFull, keySet, keySetFull, returns all non modifiable sets.
If objects (values) in the map change without invokingput()orremove()the data can be distributed using two different methods:
replicate(boolean)andreplicate(Object, boolean)
These two methods are very important two understand. The map can work with two set of value objects:
1. Serializable - the entire object gets serialized each time it is replicated
2. ReplicatedMapEntry - this interface allows for a isDirty() flag and to replicate diffs if desired.
Implementing theReplicatedMapEntryinterface allows you to decide what objects get replicated and how much data gets replicated each time.
If you implement a smart AOP mechanism to detect changes in underlying objects, you can replicate only those changes by implementing the ReplicatedMapEntry interface, and return true when isDiffable() is invoked.
This map implementation doesn't have a background thread running to replicate changes. If you do have changes without invoking put/remove then you need to invoke one of the following methods:replicate(Object,boolean)- replicates only the object that belongs to the keyreplicate(boolean)- Scans the entire map for changes and replicates data
booleanvalue in thereplicatemethod used to decide whether to only replicate objects that implement theReplicatedMapEntryinterface or to replicate all objects. If an object doesn't implement theReplicatedMapEntryinterface each time the object gets replicated the entire object gets serialized, hence a call toreplicate(true)will replicate all objects in this map that are using this node as primary.
REMEMBER TO CALLbreakdown()when you are done with the map to avoid memory leaks.
TODO implement periodic sync/transfer thread- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.catalina.tribes.tipis.AbstractReplicatedMap
AbstractReplicatedMap.MapEntry<K,V>, AbstractReplicatedMap.MapMessage, AbstractReplicatedMap.MapOwner
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Field Summary
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Fields inherited from class org.apache.catalina.tribes.tipis.AbstractReplicatedMap
accessTimeout, channel, channelSendOptions, currentNode, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, externalLoaders, innerMap, mapContextName, mapMembers, mapname, mapOwner, rpcChannel, rpcTimeout, sm, stateMutex, stateTransferred
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Constructor Summary
Constructors Constructor Description LazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity, float loadFactor, ClassLoader[] cls)Creates a new mapLazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity, ClassLoader[] cls)Creates a new mapLazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls)Creates a new mapLazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls, boolean terminate)Creates a new map
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected intgetReplicateMessageType()protected intgetStateMessageType()protected Member[]publishEntryInfo(Object key, Object value)publish info about a map pair (key/value) to other nodes in the cluster-
Methods inherited from class org.apache.catalina.tribes.tipis.AbstractReplicatedMap
accept, breakdown, broadcast, clear, clear, containsKey, containsValue, entrySet, entrySetFull, equals, excludeFromSet, get, getAccessTimeout, getChannel, getChannelSendOptions, getExternalLoaders, getInternal, getMapContextName, getMapMembers, getMapMembers, getMapMembersExcl, getMapOwner, getNextBackupIndex, getNextBackupNode, getRpcChannel, getRpcTimeout, getStateMutex, hashCode, heartbeat, init, inSet, isEmpty, isStateTransferred, keySet, keySetFull, leftOver, mapMemberAdded, memberAdded, memberAlive, memberDisappeared, messageReceived, ping, printMap, put, put, putAll, remove, remove, replicate, replicate, replyRequest, setAccessTimeout, setChannelSendOptions, setExternalLoaders, setMapOwner, size, sizeFull, transferState, values, wrap
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Constructor Detail
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LazyReplicatedMap
public LazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity, float loadFactor, ClassLoader[] cls)
Creates a new map- Parameters:
owner- The map ownerchannel- The channel to use for communicationtimeout- long - timeout for RPC messagesmapContextName- String - unique name for this map, to allow multiple maps per channelinitialCapacity- int - the size of this map, see HashMaploadFactor- float - load factor, see HashMapcls- Class loaders
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LazyReplicatedMap
public LazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, int initialCapacity, ClassLoader[] cls)
Creates a new map- Parameters:
owner- The map ownerchannel- The channel to use for communicationtimeout- long - timeout for RPC messagesmapContextName- String - unique name for this map, to allow multiple maps per channelinitialCapacity- int - the size of this map, see HashMapcls- Class loaders
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LazyReplicatedMap
public LazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls)
Creates a new map- Parameters:
owner- The map ownerchannel- The channel to use for communicationtimeout- long - timeout for RPC messagesmapContextName- String - unique name for this map, to allow multiple maps per channelcls- Class loaders
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LazyReplicatedMap
public LazyReplicatedMap(AbstractReplicatedMap.MapOwner owner, Channel channel, long timeout, String mapContextName, ClassLoader[] cls, boolean terminate)
Creates a new map- Parameters:
owner- The map ownerchannel- The channel to use for communicationtimeout- long - timeout for RPC messagesmapContextName- String - unique name for this map, to allow multiple maps per channelcls- Class loadersterminate- boolean - Flag for whether to terminate this map that failed to start.
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Method Detail
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getStateMessageType
protected int getStateMessageType()
- Specified by:
getStateMessageTypein classAbstractReplicatedMap<K,V>
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getReplicateMessageType
protected int getReplicateMessageType()
- Specified by:
getReplicateMessageTypein classAbstractReplicatedMap<K,V>
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publishEntryInfo
protected Member[] publishEntryInfo(Object key, Object value) throws ChannelException
publish info about a map pair (key/value) to other nodes in the cluster- Specified by:
publishEntryInfoin classAbstractReplicatedMap<K,V>- Parameters:
key- Objectvalue- Object- Returns:
- Member - the backup node
- Throws:
ChannelException- Cluster error
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