CopyOnWriteMap (Atlassian Plugins

java.lang.Object
- com.atlassian.util.concurrent.CopyOnWriteMap<K,V>
- - com.atlassian.plugin.util.concurrent.CopyOnWriteMap<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

Serializable, ConcurrentMap<K,V>, Map<K,V>

Deprecated.
since 2.5.0 please use the CopyOnWriteMap instead as it has some important features and some bug fixes. This version is no longer maintained.
```
@Deprecated
public abstract class CopyOnWriteMap<K,V>
extends com.atlassian.util.concurrent.CopyOnWriteMap<K,V>
```
A thread-safe variant of Map in which all mutative operations (the "destructive" operations described by Map put, remove and so on) are implemented by making a fresh copy of the underlying map.
This is ordinarily too costly, but may be more efficient than alternatives when traversal operations vastly out-number mutations, and is useful when you cannot or don't want to synchronize traversals, yet need to preclude interference among concurrent threads. The "snapshot" style iterators on the collections returned by entrySet(), keySet() and values() use a reference to the internal map at the point that the iterator was created. This map never changes during the lifetime of the iterator, so interference is impossible and the iterator is guaranteed not to throw ConcurrentModificationException. The iterators will not reflect additions, removals, or changes to the list since the iterator was created. Removing elements via these iterators is not supported. The mutable operations on these collections (remove, retain etc.) are supported but as with the Map interface, add and addAll are not and throw UnsupportedOperationException.
The actual copy is performed by an abstract CopyOnWriteMap.copy(Map) method. The method is responsible for the underlying Map implementation (for instance a HashMap, TreeMap, LinkedHashMap etc.) and therefore the semantics of what this map will cope with as far as null keys and values, iteration ordering etc. See the note below about suitable candidates for underlying Map implementations
There are supplied implementations for the common Collections Map implementations via the CopyOnWriteMaps static factory methods.
Collection views of the keys, values and entries are modifiable and will cause a copy.
Please note that the thread-safety guarantees are limited to the thread-safety of the non-mutative (non-destructive) operations of the underlying map implementation. For instance some implementations such as WeakHashMap and LinkedHashMap with access ordering are actually structurally modified by the get(Object) method and are therefore not suitable candidates as delegates for this class.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`com.atlassian.util.concurrent.AbstractCopyOnWriteMap.CollectionView<E>`
`static class`	`com.atlassian.util.concurrent.AbstractCopyOnWriteMap.View<K,V>`

Nested classes/interfaces inherited from class com.atlassian.util.concurrent.CopyOnWriteMap
com.atlassian.util.concurrent.CopyOnWriteMap.Builder<K,V>

Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>

Constructor Summary

Constructors
Constructor and Description
`CopyOnWriteMap()` Deprecated. Create a new empty `CopyOnWriteMap`.
`CopyOnWriteMap(Map<? extends K,? extends V> map)` Deprecated. Create a new `CopyOnWriteMap` with the supplied `Map` to initialize the values.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`clear()`
`boolean`	`containsKey(Object arg0)`
`boolean`	`containsValue(Object arg0)`
`protected M`	`copy()`
`Set<Map.Entry<K,V>>`	`entrySet()`
`boolean`	`equals(Object arg0)`
`V`	`get(Object arg0)`
`protected M`	`getDelegate()`
`int`	`hashCode()`
`boolean`	`isEmpty()`
`Set<K>`	`keySet()`
`static <K,V> CopyOnWriteMap<K,V>`	`newHashMap()` Deprecated. Creates a new `CopyOnWriteMap` with an underlying `HashMap`.
`static <K,V> CopyOnWriteMap<K,V>`	`newHashMap(Map<? extends K,? extends V> map)` Deprecated. Creates a new `CopyOnWriteMap` with an underlying `HashMap` using the supplied map as the initial values.
`static <K,V> CopyOnWriteMap<K,V>`	`newLinkedMap()` Deprecated. Creates a new `CopyOnWriteMap` with an underlying `LinkedHashMap`.
`static <K,V> CopyOnWriteMap<K,V>`	`newLinkedMap(Map<? extends K,? extends V> map)` Deprecated. Creates a new `CopyOnWriteMap` with an underlying `LinkedHashMap` using the supplied map as the initial values.
`V`	`put(K arg0, V arg1)`
`void`	`putAll(Map<? extends K,? extends V> arg0)`
`V`	`remove(Object arg0)`
`protected void`	`set(M arg0)`
`int`	`size()`
`Collection<V>`	`values()`

Methods inherited from class com.atlassian.util.concurrent.CopyOnWriteMap
builder, copy

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

Methods inherited from interface java.util.concurrent.ConcurrentMap
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll

- Constructor Detail
  - CopyOnWriteMap
```
public CopyOnWriteMap(Map<? extends K,? extends V> map)
```
    Deprecated.
    
    Create a new CopyOnWriteMap with the supplied Map to initialize the values.
    
    Parameters:
    
    map - the initial map to initialize with
  - CopyOnWriteMap
```
public CopyOnWriteMap()
```
    Deprecated.
    
    Create a new empty CopyOnWriteMap.
- Method Detail
  - newHashMap
```
public static <K,V> CopyOnWriteMap<K,V> newHashMap()
```
    Deprecated.
    
    Creates a new CopyOnWriteMap with an underlying HashMap.
  - newHashMap
```
public static <K,V> CopyOnWriteMap<K,V> newHashMap(Map<? extends K,? extends V> map)
```
    Deprecated.
    
    Creates a new CopyOnWriteMap with an underlying HashMap using the supplied map as the initial values.
  - newLinkedMap
```
public static <K,V> CopyOnWriteMap<K,V> newLinkedMap()
```
    Deprecated.
    
    Creates a new CopyOnWriteMap with an underlying LinkedHashMap. Iterators for this map will be return elements in insertion order.
  - newLinkedMap
```
public static <K,V> CopyOnWriteMap<K,V> newLinkedMap(Map<? extends K,? extends V> map)
```
    Deprecated.
    
    Creates a new CopyOnWriteMap with an underlying LinkedHashMap using the supplied map as the initial values. Iterators for this map will be return elements in insertion order.
  - clear
```
public final void clear()
```
    Specified by:
    
    clear in interface Map<K,V>
  - remove
```
public final V remove(Object arg0)
```
    Specified by:
    
    remove in interface Map<K,V>
  - put
```
public final V put(K arg0,
                   V arg1)
```
    Specified by:
    
    put in interface Map<K,V>
  - putAll
```
public final void putAll(Map<? extends K,? extends V> arg0)
```
    Specified by:
    
    putAll in interface Map<K,V>
  - copy
```
protected M copy()
```
  - set
```
protected void set(M arg0)
```
  - entrySet
```
public final Set<Map.Entry<K,V>> entrySet()
```
    Specified by:
    
    entrySet in interface Map<K,V>
  - keySet
```
public final Set<K> keySet()
```
    Specified by:
    
    keySet in interface Map<K,V>
  - values
```
public final Collection<V> values()
```
    Specified by:
    
    values in interface Map<K,V>
  - containsKey
```
public final boolean containsKey(Object arg0)
```
    Specified by:
    
    containsKey in interface Map<K,V>
  - containsValue
```
public final boolean containsValue(Object arg0)
```
    Specified by:
    
    containsValue in interface Map<K,V>
  - get
```
public final V get(Object arg0)
```
    Specified by:
    
    get in interface Map<K,V>
  - isEmpty
```
public final boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface Map<K,V>
  - size
```
public final int size()
```
    Specified by:
    
    size in interface Map<K,V>
  - equals
```
public final boolean equals(Object arg0)
```
    Specified by:
    
    equals in interface Map<K,V>
    
    Overrides:
    
    equals in class Object
  - hashCode
```
public final int hashCode()
```
    Specified by:
    
    hashCode in interface Map<K,V>
    
    Overrides:
    
    hashCode in class Object
  - getDelegate
```
protected final M getDelegate()
```

Class CopyOnWriteMap<K,V>

Nested Class Summary

Nested classes/interfaces inherited from class com.atlassian.util.concurrent.CopyOnWriteMap

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

Constructor Summary

Method Summary

Methods inherited from class com.atlassian.util.concurrent.CopyOnWriteMap

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.concurrent.ConcurrentMap

Constructor Detail

CopyOnWriteMap

CopyOnWriteMap

Method Detail

newHashMap

newHashMap

newLinkedMap

newLinkedMap

clear

remove

put

putAll

copy

set

entrySet

keySet

values

containsKey

containsValue

get

isEmpty

size

equals

hashCode

getDelegate