com.jthreadkit.collection
Class WrappedSizeMonitoredMap

java.lang.Object
  |
  +--com.jthreadkit.AbstractSizeMonitored
        |
        +--com.jthreadkit.collection.WrappedSizeMonitoredMap

All Implemented Interfaces:

AccessibleLock, Map, SimpleShutdown, SizeMonitored, SizeMonitoredMap, TimedOutExceptionOption

Direct Known Subclasses:

WrappedSizeMonitoredSortedMap

public class WrappedSizeMonitoredMap

extends AbstractSizeMonitored

implements SizeMonitoredMap, Map, SizeMonitored

Used to wrap an instance of Map with synchronization and implementation of all the methods of SizeMonitored. This class can be used like this:

SizeMonitoredMap smm = new WrappedSizeMonitoredMap(new HashMap()); SizeMonitored sm = smm; // can be viewed as a SizeMonitored Map m = smm; // can be viewed as a Map too

Note that when possible it's best to avoid keeping a direct reference to the underlying "raw" Map (like this example above). This makes accidental use of the un-synchronized one impossible.

All method calls are synchronized on the object returned by getLockObject(). The object to lock on can be specified during construction or defaults to this. [There is no need to wrap the raw or resulting wrapped object by using Collections.synchronizedMap().]

To safely iterate in an multithreaded environment, use code like this:

SizeMonitoredMap smm = //... Set set = smm.keySet(); // safely gets the set of keys //... synchronized ( smm.getLockObject() ) { // note: use smm lock Iterator iter = set.iterator(); // note: key iterator from set while ( iter.hasNext() ) { Object obj = iter.next(); //... } }

The methods of SizeMonitored are nicely combined so that we can have one thread doing something like this:

smm.waitUntilEmpty();

while another thread is modifying (adding and removing elements) the object.

Inner classes inherited from class java.util.Map

Map.Entry

Constructor Summary

WrappedSizeMonitoredMap(Map map)

WrappedSizeMonitoredMap(Map map, Object lock, boolean useTimedOutException)

Method Summary

void	clear()
boolean	containsKey(Object o)
boolean	containsValue(Object o)
Set	entrySet()
boolean	equals(Object o)
Object	get(Object key)
int	hashCode()
Set	keySet()
Object	put(Object key, Object value)
void	putAll(Map additions)
Object	remove(Object key)
int	setCapacity(int requestedCapacity) Not supported, UnsupportedOperationException will always be thrown.
int	size()
Collection	values()

Methods inherited from class com.jthreadkit.AbstractSizeMonitored

addSizeChangeListener, getCapacity, getLockObject, getSize, isEmpty, isFull, isUseTimedOutExceptionSet, removeSizeChangeListener, setUseTimedOutException, shutdown, shutdownWhenEmpty, waitForSizeToChange, waitForSizeToChange, waitForSizeToClimbTo, waitForSizeToClimbTo, waitForSizeToFallTo, waitForSizeToFallTo, waitUntilEmpty, waitUntilEmpty, waitUntilFull, waitUntilFull, waitUntilSizeInRange, waitUntilSizeInRange, waitUntilSizeIs, waitUntilSizeIs, waitWhileEmpty, waitWhileEmpty, waitWhileFull, waitWhileFull, waitWhileSizeInRange, waitWhileSizeInRange, waitWhileSizeIs, waitWhileSizeIs

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.jthreadkit.SizeMonitored

addSizeChangeListener, getCapacity, getSize, isEmpty, isFull, removeSizeChangeListener, shutdownWhenEmpty, waitForSizeToChange, waitForSizeToChange, waitForSizeToClimbTo, waitForSizeToClimbTo, waitForSizeToFallTo, waitForSizeToFallTo, waitUntilEmpty, waitUntilEmpty, waitUntilFull, waitUntilFull, waitUntilSizeInRange, waitUntilSizeInRange, waitUntilSizeIs, waitUntilSizeIs, waitWhileEmpty, waitWhileEmpty, waitWhileFull, waitWhileFull, waitWhileSizeInRange, waitWhileSizeInRange, waitWhileSizeIs, waitWhileSizeIs

Methods inherited from interface com.jthreadkit.AccessibleLock

getLockObject

Methods inherited from interface com.jthreadkit.SimpleShutdown

shutdown

Methods inherited from interface com.jthreadkit.TimedOutExceptionOption

isUseTimedOutExceptionSet, setUseTimedOutException

Methods inherited from interface java.util.Map

isEmpty

Constructor Detail

WrappedSizeMonitoredMap

public WrappedSizeMonitoredMap(Map map,
                               Object lock,
                               boolean useTimedOutException)

WrappedSizeMonitoredMap

public WrappedSizeMonitoredMap(Map map)

Method Detail

setCapacity

public int setCapacity(int requestedCapacity)
                throws UnsupportedOperationException

Not supported, UnsupportedOperationException will always be thrown. Capacity is effectively Integer.MAX_VALUE and can't be lowered.

Specified by:

setCapacity in interface SizeMonitored

Overrides:

setCapacity in class AbstractSizeMonitored

Following copied from interface: com.jthreadkit.SizeMonitored

Parameters:

requestedCapacity - the desired new capacity. This number is silently increased to minimum of 1 and/or the value returned from SizeMonitored.getSize() if necessary.

Returns:

the actual new capacity--may be larger than the requested capacity.

Throws:

ShutdownException - see explanation.

clear

public void clear()
           throws ShutdownException

Specified by:

clear 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

entrySet

public Set entrySet()

Specified by:

entrySet in interface Map

equals

public boolean equals(Object o)

Specified by:

equals in interface Map

Overrides:

equals in class Object

get

public Object get(Object key)

Specified by:

get in interface Map

hashCode

public int hashCode()

Specified by:

hashCode in interface Map

Overrides:

hashCode in class Object

keySet

public Set keySet()

Specified by:

keySet in interface Map

put

public Object put(Object key,
                  Object value)
           throws ShutdownException

Specified by:

put in interface Map

putAll

public void putAll(Map additions)
            throws ShutdownException

Specified by:

putAll in interface Map

remove

public Object remove(Object key)
              throws ShutdownException

Specified by:

remove in interface Map

size

public int size()

Specified by:

size in interface Map

values

public Collection values()

Specified by:

values in interface Map