Partitions (Lettuce 6.1.4.RELEASE API)

java.lang.Object
- io.lettuce.core.cluster.models.partitions.Partitions

All Implemented Interfaces:

Iterable<RedisClusterNode>, Collection<RedisClusterNode>
```
public class Partitions
extends Object
implements Collection<RedisClusterNode>
```
Cluster topology view. An instance of Partitions provides access to the partitions of a Redis Cluster. A partition is represented by a Redis Cluster node that has a nodeId and connection point details.
Partitions can be looked up by nodeId or slot (masters only). A nodeId can be migrated to a different host. Partitions are cached to ensure a cheap lookup by slot. Users of Partitions are required to call updateCache() after topology changes occur.
Topology changes are:
- Changes in RedisClusterNode.NodeFlag.UPSTREAM/ RedisClusterNode.NodeFlag.REPLICA state
- Newly added or removed nodes to/from the Redis Cluster
- Changes in RedisClusterNode.getSlots() responsibility
- Changes to the replication source (the master of a replica)
- Changes to the RedisClusterNode.getUri() () connection point}
All query/read operations use the read-only view. Updates to Partitions are performed in an atomic way. Changes to the read-only cache become visible after the partition update is completed.
Since:

3.0

Author:

Mark Paluch

Constructor Summary

Constructors
Constructor and Description

Partitions()

Constructors
Constructor and Description
`Partitions()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(RedisClusterNode redisClusterNode)` Adds the `RedisClusterNode` to this `Partitions`.
`boolean`	`addAll(Collection<? extends RedisClusterNode> c)` Add all `nodes` from the given collection and update the read-view/caches.
`void`	`addPartition(RedisClusterNode partition)` Adds a partition without updating the read view/cache.
`void`	`clear()` Removes all `nodes` and update the read-view/caches.
`Partitions`	`clone()` Create a deep copy of this `Partitions` object.
`boolean`	`contains(Object o)` Returns `true` if this `Partitions` contains the specified element.
`boolean`	`containsAll(Collection<?> c)` Returns `true` if this collection contains all of the elements in the specified collection.
`RedisClusterNode`	`getPartition(int index)` Returns the `RedisClusterNode` at `index`.
`RedisClusterNode`	`getPartition(String host, int port)` Retrieve a `RedisClusterNode` by its hostname/port considering node aliases.
`RedisClusterNode`	`getPartitionByNodeId(String nodeId)` Retrieve a `RedisClusterNode` by its node id.
`RedisClusterNode`	`getPartitionBySlot(int slot)` Retrieve a `RedisClusterNode` by its slot number.
`List<RedisClusterNode>`	`getPartitions()` Returns the internal `List` of `RedisClusterNode` that holds the partition source.
`boolean`	`isEmpty()` Returns `true` if this `Partitions` contains no elements using the read-view.
`Iterator<RedisClusterNode>`	`iterator()` Returns an iterator over the `nodes` in this `Partitions` from the read-view.
`void`	`reload(List<RedisClusterNode> partitions)` Update partitions and rebuild slot cache.
`boolean`	`remove(Object o)` Remove the element from this `Partitions`.
`boolean`	`removeAll(Collection<?> c)` Remove all `nodes` from the `Partitions` using elements from the given collection and update the read-view/caches.
`boolean`	`retainAll(Collection<?> c)` Retains only the elements in this `Partitions` that are contained in the specified collection (optional operation)and update the read-view/caches.
`int`	`size()`
`Object[]`	`toArray()` Returns an array containing all of the elements in this `Partitions` using the read-view.
`<T> T[]`	`toArray(T[] a)` Returns an array containing all of the elements in this `Partitions` using the read-view.
`String`	`toString()`
`void`	`updateCache()` Update the partition cache.

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

Methods inherited from interface java.util.Collection
equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - Partitions
```
public Partitions()
```
- Method Detail
  - clone
```
public Partitions clone()
```
    Create a deep copy of this Partitions object.
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    a deep copy of this Partitions object.
  - getPartitionBySlot
```
public RedisClusterNode getPartitionBySlot(int slot)
```
    Retrieve a RedisClusterNode by its slot number. This method does not distinguish between masters and slaves.
    
    Parameters:
    
    slot - the slot hash.
    
    Returns:
    
    the RedisClusterNode or null if not found.
  - getPartitionByNodeId
```
public RedisClusterNode getPartitionByNodeId(String nodeId)
```
    Retrieve a RedisClusterNode by its node id.
    
    Parameters:
    
    nodeId - the nodeId.
    
    Returns:
    
    the RedisClusterNode or null if not found.
  - getPartition
```
public RedisClusterNode getPartition(String host,
                                     int port)
```
    Retrieve a RedisClusterNode by its hostname/port considering node aliases.
    
    Parameters:
    
    host - hostname.
    
    port - port number.
    
    Returns:
    
    the RedisClusterNode or null if not found.
  - updateCache
```
public void updateCache()
```
    Update the partition cache. Updates are necessary after the partition details have changed.
  - iterator
```
public Iterator<RedisClusterNode> iterator()
```
    Returns an iterator over the nodes in this Partitions from the read-view. The Iterator remains consistent during partition updates with the nodes that have been part of the Partitions . Nodes added/removed during iteration/after obtaining the Iterator don't become visible during iteration but upon the next call to iterator().
    
    Specified by:
    
    iterator in interface Iterable<RedisClusterNode>
    
    Specified by:
    
    iterator in interface Collection<RedisClusterNode>
    
    Returns:
    
    an iterator over the nodes in this Partitions from the read-view.
  - getPartitions
```
public List<RedisClusterNode> getPartitions()
```
    Returns the internal List of RedisClusterNode that holds the partition source. This List is used to populate partition caches and should not be used directly and subject to change by refresh processes. Access (read/write) requires synchronization on getPartitions().
    
    Returns:
    
    the internal partition source.
  - addPartition
```
public void addPartition(RedisClusterNode partition)
```
    Adds a partition without updating the read view/cache.
    
    Parameters:
    
    partition - the partition
  - size
```
public int size()
```
    Specified by:
    
    size in interface Collection<RedisClusterNode>
    
    Returns:
    
    the number of elements using the read-view.
  - getPartition
```
public RedisClusterNode getPartition(int index)
```
    Returns the RedisClusterNode at index.
    
    Parameters:
    
    index - the index
    
    Returns:
    
    the requested element using the read-view.
  - reload
```
public void reload(List<RedisClusterNode> partitions)
```
    Update partitions and rebuild slot cache.
    
    Parameters:
    
    partitions - list of new partitions
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this Partitions contains no elements using the read-view.
    
    Specified by:
    
    isEmpty in interface Collection<RedisClusterNode>
    
    Returns:
    
    true if this Partitions contains no elements using the read-view.
  - contains
```
public boolean contains(Object o)
```
    Returns true if this Partitions contains the specified element.
    
    Specified by:
    
    contains in interface Collection<RedisClusterNode>
    
    Parameters:
    
    o - the element to check for
    
    Returns:
    
    true if this Partitions contains the specified element
  - addAll
```
public boolean addAll(Collection<? extends RedisClusterNode> c)
```
    Add all nodes from the given collection and update the read-view/caches.
    
    Specified by:
    
    addAll in interface Collection<RedisClusterNode>
    
    Parameters:
    
    c - must not be null
    
    Returns:
    
    true if this Partitions changed as a result of the call
  - removeAll
```
public boolean removeAll(Collection<?> c)
```
    Remove all nodes from the Partitions using elements from the given collection and update the read-view/caches.
    
    Specified by:
    
    removeAll in interface Collection<RedisClusterNode>
    
    Parameters:
    
    c - must not be null
    
    Returns:
    
    true if this Partitions changed as a result of the call
  - retainAll
```
public boolean retainAll(Collection<?> c)
```
    Retains only the elements in this Partitions that are contained in the specified collection (optional operation)and update the read-view/caches. In other words, removes from this collection all of its elements that are not contained in the specified collection.
    
    Specified by:
    
    retainAll in interface Collection<RedisClusterNode>
    
    Parameters:
    
    c - must not be null
    
    Returns:
    
    true if this Partitions changed as a result of the call
  - clear
```
public void clear()
```
    Removes all nodes and update the read-view/caches.
    
    Specified by:
    
    clear in interface Collection<RedisClusterNode>
  - toArray
```
public Object[] toArray()
```
    Returns an array containing all of the elements in this Partitions using the read-view.
    
    Specified by:
    
    toArray in interface Collection<RedisClusterNode>
    
    Returns:
    
    an array containing all of the elements in this Partitions using the read-view.
  - toArray
```
public <T> T[] toArray(T[] a)
```
    Returns an array containing all of the elements in this Partitions using the read-view.
    
    Specified by:
    
    toArray in interface Collection<RedisClusterNode>
    
    Type Parameters:
    
    T - type of the array to contain the collection
    
    Parameters:
    
    a - the array into which the elements of this collection are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
    
    Returns:
    
    an array containing all of the elements in this Partitions using the read-view.
  - add
```
public boolean add(RedisClusterNode redisClusterNode)
```
    Adds the RedisClusterNode to this Partitions.
    
    Specified by:
    
    add in interface Collection<RedisClusterNode>
    
    Parameters:
    
    redisClusterNode - must not be null
    
    Returns:
    
    true if this Partitions changed as a result of the call
  - remove
```
public boolean remove(Object o)
```
    Remove the element from this Partitions.
    
    Specified by:
    
    remove in interface Collection<RedisClusterNode>
    
    Parameters:
    
    o - must not be null
    
    Returns:
    
    true if this Partitions changed as a result of the call
  - containsAll
```
public boolean containsAll(Collection<?> c)
```
    Returns true if this collection contains all of the elements in the specified collection.
    
    Specified by:
    
    containsAll in interface Collection<RedisClusterNode>
    
    Parameters:
    
    c - collection to be checked for containment in this collection, must not be null
    
    Returns:
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Partitions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

Partitions

Method Detail

clone

getPartitionBySlot

getPartitionByNodeId

getPartition

updateCache

iterator

getPartitions

addPartition

size

getPartition

reload

isEmpty

contains

addAll

removeAll

retainAll

clear

toArray

toArray

add

remove

containsAll

toString