org.apache.openjpa.util
Class AbstractLRSProxyMap<K,V>

java.lang.Object
  extended by org.apache.openjpa.util.AbstractLRSProxyMap<K,V>
All Implemented Interfaces:
Map<K,V>, Predicate, ChangeTracker, LRSProxy, MapChangeTracker, Proxy

public abstract class AbstractLRSProxyMap<K,V>
extends Object
implements Map<K,V>, LRSProxy, MapChangeTracker, Predicate

A map proxy designed for maps backed by extremely large result sets in which each call to get(java.lang.Object) or containsKey(java.lang.Object) may perform a database query. Changes to the map are tracked through a ChangeTracker. This map has the following limitations:

Author:
Abe White

Nested Class Summary
 
Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>
 
Constructor Summary
AbstractLRSProxyMap(Class<K> keyType, Class<V> valueType)
           
 
Method Summary
 void added(Object key, Object val)
          Record that the given entry was added to the map.
 void changed(Object key, Object orig, Object val)
          Record that the given entry was altered.
 void clear()
           
 boolean containsKey(Object key)
           
 boolean containsValue(Object val)
           
 Object copy(Object orig)
          Return an unproxied copy of the given instance.
protected abstract  int count()
          Return the number of entries in the map, or Integer.MAX_VALUE.
 Set<Map.Entry<K,V>> entrySet()
           
 boolean evaluate(Object obj)
           
 V get(Object key)
           
 Collection getAdded()
          Return the collection of values that need to be added to the managed container.
 Collection getChanged()
          Return the set of elements that have changed.
 ChangeTracker getChangeTracker()
          Return the change tracker for this proxy, or null if none.
 int getNextSequence()
          The next element sequence value for this proxy at load time.
 OpenJPAStateManager getOwner()
          Return the owning object.
 int getOwnerField()
          Return the owning field index.
 Collection getRemoved()
          Return the set of values that need to be removed from the managed container.
 boolean getTrackKeys()
          Whether to track keys or values.
protected abstract  boolean hasKey(Object key)
          Return whether the given key exists in the map.
protected abstract  boolean hasValue(Object value)
          Return whether the given value exists in the map.
 boolean isEmpty()
           
 boolean isTracking()
          Return true if this tracker has an up-to-date view of all the changes to the container it is managing.
protected abstract  Iterator<?> itr()
          Implement this method to return an iterator over the entries in the map.
protected abstract  Collection<K> keys(Object value)
          Return all keys for the given value.
 Set<K> keySet()
           
 V put(K key, V value)
           
 void putAll(Map<? extends K,? extends V> m)
           
 V remove(Object key)
           
 void removed(Object key, Object val)
          Record that the given entry was removed from the map.
 void setNextSequence(int seq)
          The maximum element sequence value for this proxy at load time.
 void setOwner(OpenJPAStateManager sm, int field)
          Reset the state of the proxy, and set the owning instance of the proxy and the name of the field it is assigned to.
 void setTrackKeys(boolean keys)
          Whether to track keys or values.
 int size()
           
 void startTracking()
          Reset the state of the change tracker, and turn change tracking back on if it has been disabled.
 void stopTracking()
          Tell the tracker to stop tracking changes for its container.
protected abstract  V value(Object key)
          Return the value of the given key.
 Collection<V> values()
           
protected  Object writeReplace()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface java.util.Map
equals, hashCode
 

Constructor Detail

AbstractLRSProxyMap

public AbstractLRSProxyMap(Class<K> keyType,
                           Class<V> valueType)
Method Detail

setOwner

public void setOwner(OpenJPAStateManager sm,
                     int field)
Description copied from interface: Proxy
Reset the state of the proxy, and set the owning instance of the proxy and the name of the field it is assigned to. Set to null to indicate that the proxy is no longer managed.

Specified by:
setOwner in interface Proxy

getOwner

public OpenJPAStateManager getOwner()
Description copied from interface: Proxy
Return the owning object.

Specified by:
getOwner in interface Proxy

getOwnerField

public int getOwnerField()
Description copied from interface: Proxy
Return the owning field index.

Specified by:
getOwnerField in interface Proxy

getChangeTracker

public ChangeTracker getChangeTracker()
Description copied from interface: Proxy
Return the change tracker for this proxy, or null if none.

Specified by:
getChangeTracker in interface Proxy

copy

public Object copy(Object orig)
Description copied from interface: Proxy
Return an unproxied copy of the given instance. This method is used by proxy managers to create backup values for use in rollback.

Specified by:
copy in interface Proxy

size

public int size()
Specified by:
size in interface Map<K,V>

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface Map<K,V>

containsKey

public boolean containsKey(Object key)
Specified by:
containsKey in interface Map<K,V>

containsValue

public boolean containsValue(Object val)
Specified by:
containsValue in interface Map<K,V>

get

public V get(Object key)
Specified by:
get in interface Map<K,V>

put

public V put(K key,
             V value)
Specified by:
put in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> m)
Specified by:
putAll in interface Map<K,V>

remove

public V remove(Object key)
Specified by:
remove in interface Map<K,V>

clear

public void clear()
Specified by:
clear in interface Map<K,V>

keySet

public Set<K> keySet()
Specified by:
keySet in interface Map<K,V>

values

public Collection<V> values()
Specified by:
values in interface Map<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()
Specified by:
entrySet in interface Map<K,V>

writeReplace

protected Object writeReplace()
                       throws ObjectStreamException
Throws:
ObjectStreamException

hasKey

protected abstract boolean hasKey(Object key)
Return whether the given key exists in the map.


hasValue

protected abstract boolean hasValue(Object value)
Return whether the given value exists in the map.


keys

protected abstract Collection<K> keys(Object value)
Return all keys for the given value.


value

protected abstract V value(Object key)
Return the value of the given key.


itr

protected abstract Iterator<?> itr()
Implement this method to return an iterator over the entries in the map. Each returned object must implement the Map.Entry interface. This method may be invoked multiple times. The iterator does not have to support the Iterator.remove() method, and may implement Closeable.


count

protected abstract int count()
Return the number of entries in the map, or Integer.MAX_VALUE.


evaluate

public boolean evaluate(Object obj)
Specified by:
evaluate in interface Predicate

isTracking

public boolean isTracking()
Description copied from interface: ChangeTracker
Return true if this tracker has an up-to-date view of all the changes to the container it is managing.

Specified by:
isTracking in interface ChangeTracker

startTracking

public void startTracking()
Description copied from interface: ChangeTracker
Reset the state of the change tracker, and turn change tracking back on if it has been disabled.

Specified by:
startTracking in interface ChangeTracker

stopTracking

public void stopTracking()
Description copied from interface: ChangeTracker
Tell the tracker to stop tracking changes for its container.

Specified by:
stopTracking in interface ChangeTracker

getTrackKeys

public boolean getTrackKeys()
Description copied from interface: MapChangeTracker
Whether to track keys or values. Defaults to keys. If you set to values, it is assumed there is a 1-1 correlation between keys and values in this map.

Specified by:
getTrackKeys in interface MapChangeTracker

setTrackKeys

public void setTrackKeys(boolean keys)
Description copied from interface: MapChangeTracker
Whether to track keys or values. Defaults to keys. If you set to values, it is assumed there is a 1-1 correlation between keys and values in this map.

Specified by:
setTrackKeys in interface MapChangeTracker

getAdded

public Collection getAdded()
Description copied from interface: ChangeTracker
Return the collection of values that need to be added to the managed container.

Specified by:
getAdded in interface ChangeTracker

getRemoved

public Collection getRemoved()
Description copied from interface: ChangeTracker
Return the set of values that need to be removed from the managed container.

Specified by:
getRemoved in interface ChangeTracker

getChanged

public Collection getChanged()
Description copied from interface: ChangeTracker
Return the set of elements that have changed. In maps, this marks a possible change in value for a key. In collections, this marks an element that has been removed and re-added.

Specified by:
getChanged in interface ChangeTracker

added

public void added(Object key,
                  Object val)
Description copied from interface: MapChangeTracker
Record that the given entry was added to the map.

Specified by:
added in interface MapChangeTracker

removed

public void removed(Object key,
                    Object val)
Description copied from interface: MapChangeTracker
Record that the given entry was removed from the map.

Specified by:
removed in interface MapChangeTracker

changed

public void changed(Object key,
                    Object orig,
                    Object val)
Description copied from interface: MapChangeTracker
Record that the given entry was altered.

Specified by:
changed in interface MapChangeTracker

getNextSequence

public int getNextSequence()
Description copied from interface: ChangeTracker
The next element sequence value for this proxy at load time. If the data store keeps this proxy's data in sequence order but allows holes for removed objects, the implementation can set the next sequence at load time, then retrieve it and start from there for added objects at flush time. This value is set back to 0 if the proxy stops tracking changes. For ordered proxies, it is set to the proxy's size when the proxy starts tracking changes again.

Specified by:
getNextSequence in interface ChangeTracker

setNextSequence

public void setNextSequence(int seq)
Description copied from interface: ChangeTracker
The maximum element sequence value for this proxy at load time. If the data store keeps this proxy's data in sequence order but allows holes for removed objects, the implementation can set the next sequence at load time, then retrieve it and start from there for added objects at flush time. This value is set back to 0 if the proxy stops tracking changes. For ordered proxies, it is set to the proxy's size when the proxy starts tracking changes again.

Specified by:
setNextSequence in interface ChangeTracker


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