Package EDU.oswego.cs.dl.util.concurrent

Class SyncMap

java.lang.Object

EDU.oswego.cs.dl.util.concurrent.SyncMap

All Implemented Interfaces:

Map

Direct Known Subclasses:

SyncSortedMap

public class SyncMap
extends Object
implements Map

SyncMaps wrap Sync-based control around java.util.Maps. They operate in the same way as SyncCollection.

Reader operations are

• size
• isEmpty
• get
• containsKey
• containsValue
• keySet
• entrySet
• values

Writer operations are:

• put
• putAll
• remove
• clear

[ Introduction to this package. ]

See Also:

SyncCollection

Nested Class Summary

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

Map.Entry<K extends Object,V extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
protected Map	c_
protected Sync	rd_
protected SynchronizedLong	syncFailures_
protected Sync	wr_

Constructor Summary

Constructors

Constructor	Description
SyncMap(Map map, ReadWriteLock rwl)	Create a new SyncMap protecting the given map, and using the given ReadWriteLock to control reader and writer methods.
SyncMap(Map map, Sync sync)	Create a new SyncMap protecting the given map, and using the given sync to control both reader and writer methods.
SyncMap(Map map, Sync readLock, Sync writeLock)	Create a new SyncMap protecting the given map, and using the given pair of locks to control reader and writer methods.

Method Summary

Modifier and Type	Method	Description
protected void	afterRead(boolean wasInterrupted)	Clean up after a reader operation
protected boolean	beforeRead()	Try to acquire sync before a reader operation; record failure
void	clear()
boolean	containsKey(Object o)
boolean	containsValue(Object o)
Set	entrySet()
boolean	equals(Object o)
Object	get(Object key)
int	hashCode()
boolean	isEmpty()
Set	keySet()
Object	put(Object key, Object value)
void	putAll(Map coll)
Sync	readerSync()	Return the Sync object managing read-only operations
Object	remove(Object key)
int	size()
long	syncFailures()	Return the number of synchronization failures for read-only operations
Collection	values()
Sync	writerSync()	Return the Sync object managing mutative operations

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Field Detail

c_

protected final Map c_

rd_

protected final Sync rd_

wr_

protected final Sync wr_

syncFailures_

protected final SynchronizedLong syncFailures_

Constructor Detail

SyncMap

public SyncMap(Map map,
               Sync sync)

Create a new SyncMap protecting the given map, and using the given sync to control both reader and writer methods. Common, reasonable choices for the sync argument include Mutex, ReentrantLock, and Semaphores initialized to 1.

SyncMap

public SyncMap(Map map,
               ReadWriteLock rwl)

Create a new SyncMap protecting the given map, and using the given ReadWriteLock to control reader and writer methods.

SyncMap

public SyncMap(Map map,
               Sync readLock,
               Sync writeLock)

Create a new SyncMap protecting the given map, and using the given pair of locks to control reader and writer methods.

Method Detail

readerSync

public Sync readerSync()

Return the Sync object managing read-only operations

writerSync

public Sync writerSync()

Return the Sync object managing mutative operations

syncFailures

public long syncFailures()

Return the number of synchronization failures for read-only operations

beforeRead

protected boolean beforeRead()

Try to acquire sync before a reader operation; record failure

afterRead

protected void afterRead(boolean wasInterrupted)

Clean up after a reader operation

hashCode

public int hashCode()

Specified by:

hashCode in interface Map

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Specified by:

equals in interface Map

Overrides:

equals in class Object

size

public int size()

Specified by:

size in interface Map

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map

containsKey

public boolean containsKey(Object o)

Specified by:

containsKey in interface Map

containsValue

public boolean containsValue(Object o)

Specified by:

containsValue in interface Map

get

public Object get(Object key)

Specified by:

get in interface Map

put

public Object put(Object key,
                  Object value)

Specified by:

put in interface Map

remove

public Object remove(Object key)

Specified by:

remove in interface Map

putAll

public void putAll(Map coll)

Specified by:

putAll in interface Map

clear

public void clear()

Specified by:

clear in interface Map

keySet

public Set keySet()

Specified by:

keySet in interface Map

entrySet

public Set entrySet()

Specified by:

entrySet in interface Map

values

public Collection values()

Specified by:

values in interface Map