PartitionedHashMap

java.lang.Object
- org.jgroups.blocks.PartitionedHashMap<K,V>

All Implemented Interfaces:

MembershipListener
```
public class PartitionedHashMap<K,V>
extends java.lang.Object
implements MembershipListener
```
Hashmap which distributes its keys and values across the cluster. A PUT/GET/REMOVE computes the cluster node to which or from which to get/set the key/value from a hash of the key and then forwards the request to the remote cluster node. We also maintain a local cache (L1 cache) which is a bounded cache that caches retrieved keys/values.
Todos:
1. Use MarshalledValue to keep track of byte[] buffers, and be able to compute the exact size of the cache. This is good for maintaining a bounded cache (rather than using the number of entries)
2. Provide a better consistent hashing algorithm than ConsistentHashFunction as default
3. GUI (showing at least the topology and L1 and L2 caches)
4. Notifications (puts, removes, gets etc)
5. Invalidation of L1 caches (if used) on removal/put of item
6. Benchmarks, comparison to memcached
7. Documentation, comparison to memcached
Author:

Bela Ban

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class PartitionedHashMap.ConsistentHashFunction<K>

static interface PartitionedHashMap.HashFunction<K>

Nested Classes
Modifier and Type	Class and Description
`static class`	`PartitionedHashMap.ConsistentHashFunction<K>`
`static interface`	`PartitionedHashMap.HashFunction<K>`

Field Summary

Fields
Modifier and Type Field and Description

protected static java.util.Map<java.lang.Short,java.lang.reflect.Method> methods

Fields
Modifier and Type	Field and Description
`protected static java.util.Map<java.lang.Short,java.lang.reflect.Method>`	`methods`

Constructor Summary

Constructors
Constructor and Description

PartitionedHashMap(java.lang.String props, java.lang.String cluster_name)

Constructors
Constructor and Description
`PartitionedHashMap(java.lang.String props, java.lang.String cluster_name)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Cache.Value<V>`	`_get(K key)`
`V`	`_put(K key, V val, long caching_time)`
`V`	`_remove(K key)`
`void`	`addMembershipListener(MembershipListener l)`
`void`	`block()` Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages.
`java.lang.String`	`dump()`
`V`	`get(K key)`
`long`	`getCachingTime()`
`long`	`getCallTimeout()`
`java.lang.String`	`getClusterName()`
`PartitionedHashMap.HashFunction`	`getHashFunction()`
`Cache<K,V>`	`getL1Cache()`
`Cache<K,V>`	`getL2Cache()`
`Address`	`getLocalAddress()`
`java.lang.String`	`getLocalAddressAsString()`
`java.lang.String`	`getProps()`
`java.lang.String`	`getView()`
`boolean`	`isL1CacheEnabled()`
`boolean`	`isMigrateData()`
`void`	`put(K key, V val)`
`void`	`put(K key, V val, long caching_time)` Adds a key/value to the cache, replacing a previous item if there was one
`void`	`remove(K key)`
`void`	`removeMembershipListener(MembershipListener l)`
`void`	`setCachingTime(long caching_time)`
`void`	`setCallTimeout(long call_timeout)`
`void`	`setClusterName(java.lang.String cluster_name)`
`void`	`setHashFunction(PartitionedHashMap.HashFunction<K> hash_function)`
`void`	`setL1Cache(Cache<K,V> cache)`
`void`	`setL2Cache(Cache<K,V> cache)`
`void`	`setMigrateData(boolean migrate_data)`
`void`	`setProps(java.lang.String props)`
`void`	`start()`
`void`	`stop()`
`void`	`suspect(Address suspected_mbr)` Called whenever a member is suspected of having crashed, but has not yet been excluded.
`java.lang.String`	`toString()`
`void`	`unblock()` Called after the FLUSH protocol has unblocked previously blocked senders, and messages can be sent again.
`void`	`viewAccepted(View new_view)` Called when a change in membership has occurred.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - methods
```
protected static final java.util.Map<java.lang.Short,java.lang.reflect.Method> methods
```
- Constructor Detail
  - PartitionedHashMap
```
public PartitionedHashMap(java.lang.String props,
                          java.lang.String cluster_name)
```
- Method Detail
  - getProps
```
public java.lang.String getProps()
```
  - setProps
```
public void setProps(java.lang.String props)
```
  - getLocalAddress
```
public Address getLocalAddress()
```
  - getLocalAddressAsString
```
public java.lang.String getLocalAddressAsString()
```
  - getView
```
public java.lang.String getView()
```
  - isL1CacheEnabled
```
public boolean isL1CacheEnabled()
```
  - getClusterName
```
public java.lang.String getClusterName()
```
  - setClusterName
```
public void setClusterName(java.lang.String cluster_name)
```
  - getCallTimeout
```
public long getCallTimeout()
```
  - setCallTimeout
```
public void setCallTimeout(long call_timeout)
```
  - getCachingTime
```
public long getCachingTime()
```
  - setCachingTime
```
public void setCachingTime(long caching_time)
```
  - isMigrateData
```
public boolean isMigrateData()
```
  - setMigrateData
```
public void setMigrateData(boolean migrate_data)
```
  - getHashFunction
```
public PartitionedHashMap.HashFunction getHashFunction()
```
  - setHashFunction
```
public void setHashFunction(PartitionedHashMap.HashFunction<K> hash_function)
```
  - addMembershipListener
```
public void addMembershipListener(MembershipListener l)
```
  - removeMembershipListener
```
public void removeMembershipListener(MembershipListener l)
```
  - getL1Cache
```
public Cache<K,V> getL1Cache()
```
  - setL1Cache
```
public void setL1Cache(Cache<K,V> cache)
```
  - getL2Cache
```
public Cache<K,V> getL2Cache()
```
  - setL2Cache
```
public void setL2Cache(Cache<K,V> cache)
```
  - start
```
public void start()
           throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - stop
```
public void stop()
```
  - put
```
public void put(K key,
                V val)
```
  - put
```
public void put(K key,
                V val,
                long caching_time)
```
    Adds a key/value to the cache, replacing a previous item if there was one
    
    Parameters:
    
    key - The key
    
    val - The value
    
    caching_time - Time to live. -1 means never cache, 0 means cache forever. All other (positive) values are the number of milliseconds to cache the item
  - get
```
public V get(K key)
```
  - remove
```
public void remove(K key)
```
  - _put
```
public V _put(K key,
              V val,
              long caching_time)
```
  - _get
```
public Cache.Value<V> _get(K key)
```
  - _remove
```
public V _remove(K key)
```
  - viewAccepted
```
public void viewAccepted(View new_view)
```
    Description copied from interface: MembershipListener
    
    Called when a change in membership has occurred. No long running actions, sending of messages or anything that could block should be done in this callback. If some long running action needs to be performed, it should be done in a separate thread.
    Note that on reception of the first view (a new member just joined), the channel will not yet be in the connected state. This only happens when Channel.connect(String) returns.
    
    Specified by:
    
    viewAccepted in interface MembershipListener
  - suspect
```
public void suspect(Address suspected_mbr)
```
    Description copied from interface: MembershipListener
    
    Called whenever a member is suspected of having crashed, but has not yet been excluded.
    
    Specified by:
    
    suspect in interface MembershipListener
  - block
```
public void block()
```
    Description copied from interface: MembershipListener
    
    Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages. Any messages sent after returning from this callback might get blocked by the FLUSH protocol. When the FLUSH protocol is done, and messages can be sent again, the FLUSH protocol will simply unblock all pending messages. If a callback for unblocking is desired, implement MembershipListener.unblock(). Note that block() is the equivalent of reception of a BlockEvent in the pull mode.
    
    Specified by:
    
    block in interface MembershipListener
  - unblock
```
public void unblock()
```
    Description copied from interface: MembershipListener
    
    Called after the FLUSH protocol has unblocked previously blocked senders, and messages can be sent again. This callback only needs to be implemented if we require a notification of that.
    Note that during new view installation we provide guarantee that unblock invocation strictly follows view installation at some node A belonging to that view . However, some other message M may squeeze in between view and unblock callbacks. For more details see https://jira.jboss.org/jira/browse/JGRP-986
    
    Specified by:
    
    unblock in interface MembershipListener
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - dump
```
public java.lang.String dump()
```

Class PartitionedHashMap<K,V>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

methods

Constructor Detail

PartitionedHashMap

Method Detail

getProps

setProps

getLocalAddress

getLocalAddressAsString

getView

isL1CacheEnabled

getClusterName

setClusterName

getCallTimeout

setCallTimeout

getCachingTime

setCachingTime

isMigrateData

setMigrateData

getHashFunction

setHashFunction

addMembershipListener

removeMembershipListener

getL1Cache

setL1Cache

getL2Cache

setL2Cache

start

stop

put

put

get

remove

_put

_get

_remove

viewAccepted

suspect

block

unblock

toString

dump