Class ContentState
- Object
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- ContentState
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- Direct Known Subclasses:
JDBCState
,MemoryState
,VectorMosaicState
,WFSContentState
public class ContentState extends Object
The state of an entry in a DataStore, maintained on a per-transaction basis. For information maintained on a typeName basis seeContentEntry
.Data Cache Synchronization Required
The default ContentState implementation maintains cached values on a per transaction basis:
- feature type (
getFeatureType()
- number of features (
getCount()
- spatial extent (
getBounds()
This class is a "data object" used to store values and is not thread safe. It is up to clients of this class to ensure that values are set in a thread-safe / synchronized manner. For example:
ContentState state = ...; //get the count int count = state.getCount(); if ( count == -1 ) { synchronized ( state ) { count = calculateCount(); state.setCount( count ); } }
Event Notification
The list of listeners interested in event notification as features are modified and edited is stored as part of ContentState. Each notification is considered to be broadcast from a specific FeatureSource. Since several ContentFeatureStores can be on the same transaction (and thus share a ContentState) the fire methods listed here require you pass in the FeatureSource making the change; this requires that your individual FeatureWriters keep a pointer to the ContentFeatureStore which created them.You may also make use of
ContentFeatureSource.canEvent()
value offalse
allowing the base ContentFeatureStore class to take responsibility for sending event notifications.Transaction Independence
The default ContentState implementation also supports the handling of
ContentFeatureSource#canTransaction
value offalse
. The implementation asks ContentState to store aDiff
which is used to record any modifications made until commit is called.Internally a
Transaction.State
is used to notify the implementation of {Transaction.commit()
andTransaction.rollback()
.Extension
This class may be extended if your implementaiton wishes to capture additional information per transaction. A database implementation using a JDBCContentState to store a JDBC Connection remains a good example.Subclasses may extend (not override) the following methods:
Subclasses should also overridecopy()
to ensure any additional state they are keeping is correctly accounted for.- Since:
- 2.6
- Author:
- Jody Garnett (LISASoft), Justin Deoliveira, The Open Planning Project
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Field Summary
Fields Modifier and Type Field Description protected BatchFeatureEvent
batchFeatureEvent
Even used for batch notification; used to collect the bounds and feature ids generated over the course of a transaction.protected ReferencedEnvelope
bounds
cached bounds of featuresprotected int
count
cached number of featuresprotected ContentEntry
entry
entry maintaining the stateprotected SimpleFeatureType
featureType
cached feature typeprotected List<FeatureListener>
listeners
observersprotected DiffTransactionState
transactionState
Callback used to issue batch feature events when commit/rollback issued on the transaction.protected Transaction
tx
Transaction the state works from.
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Constructor Summary
Constructors Modifier Constructor Description ContentState(ContentEntry entry)
Creates a new state.protected
ContentState(ContentState state)
Creates a new state from a previous one.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addListener(FeatureListener listener)
Adds a listener for collection events.void
close()
Clears all state.ContentState
copy()
Copies the state.void
fireBatchFeatureEvent(boolean isCommit)
Notifies all waiting listeners that a commit has been issued; this notification is also sent to ourvoid
fireFeatureAdded(FeatureSource<?,?> source, Feature feature)
Used to issue a Type.ADDED FeatureEvent indicating a new feature being createdvoid
fireFeatureEvent(FeatureEvent event)
Used to issue a single FeatureEvent.void
fireFeatureRemoved(FeatureSource<?,?> source, Feature feature)
void
fireFeatureUpdated(FeatureSource<?,?> source, Feature feature, ReferencedEnvelope before)
Creates a FeatureEvent indicating that the provided feature has been changed.void
flush()
Clears cached state.BatchFeatureEvent
getBatchFeatureEvent()
ReferencedEnvelope
getBounds()
The cached spatial extent.int
getCount()
The cached number of features.ContentEntry
getEntry()
The entry which maintains the state.SimpleFeatureType
getFeatureType()
The cached feature type.Transaction
getTransaction()
The transaction associated with the state.boolean
hasListener()
Used to quickly test if any listeners are available.void
removeListener(FeatureListener listener)
Removes a listener for collection events.void
setBounds(ReferencedEnvelope bounds)
Sets the cached spatial extent.void
setCount(int count)
Sets the cached number of features.void
setFeatureType(SimpleFeatureType featureType)
Sets the cached feature type.void
setTransaction(Transaction tx)
Sets the transaction associated with the state.
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Field Detail
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tx
protected Transaction tx
Transaction the state works from.
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entry
protected ContentEntry entry
entry maintaining the state
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featureType
protected SimpleFeatureType featureType
cached feature type
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count
protected int count
cached number of features
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bounds
protected ReferencedEnvelope bounds
cached bounds of features
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batchFeatureEvent
protected BatchFeatureEvent batchFeatureEvent
Even used for batch notification; used to collect the bounds and feature ids generated over the course of a transaction.
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listeners
protected List<FeatureListener> listeners
observers
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transactionState
protected DiffTransactionState transactionState
Callback used to issue batch feature events when commit/rollback issued on the transaction.
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Constructor Detail
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ContentState
public ContentState(ContentEntry entry)
Creates a new state.- Parameters:
entry
- The entry for the state.
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ContentState
protected ContentState(ContentState state)
Creates a new state from a previous one.All state from the specified state is copied. Therefore subclasses extending this constructor should clone all mutable objects.
- Parameters:
state
- The existing state.
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Method Detail
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getEntry
public ContentEntry getEntry()
The entry which maintains the state.
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getTransaction
public Transaction getTransaction()
The transaction associated with the state.
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setTransaction
public void setTransaction(Transaction tx)
Sets the transaction associated with the state.
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getFeatureType
public final SimpleFeatureType getFeatureType()
The cached feature type.
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setFeatureType
public final void setFeatureType(SimpleFeatureType featureType)
Sets the cached feature type.
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getCount
public final int getCount()
The cached number of features.
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setCount
public final void setCount(int count)
Sets the cached number of features.
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getBounds
public final ReferencedEnvelope getBounds()
The cached spatial extent.
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setBounds
public final void setBounds(ReferencedEnvelope bounds)
Sets the cached spatial extent.
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addListener
public final void addListener(FeatureListener listener)
Adds a listener for collection events.- Parameters:
listener
- The listener to add
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removeListener
public final void removeListener(FeatureListener listener)
Removes a listener for collection events.- Parameters:
listener
- The listener to remove
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getBatchFeatureEvent
public BatchFeatureEvent getBatchFeatureEvent()
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hasListener
public final boolean hasListener()
Used to quickly test if any listeners are available.
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fireFeatureUpdated
public void fireFeatureUpdated(FeatureSource<?,?> source, Feature feature, ReferencedEnvelope before)
Creates a FeatureEvent indicating that the provided feature has been changed.This method is provided to simplify event notification for implementors by constructing a FeatureEvent internally (and then only if listeners are interested). You may find it easier to construct your own FeatureEvent using {
hasListener()
to check if you need to fire events at all.- Parameters:
source
- FeatureSource responsible for the changefeature
- The updated featurebefore
- the bounds of the feature before the change
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fireFeatureAdded
public final void fireFeatureAdded(FeatureSource<?,?> source, Feature feature)
Used to issue a Type.ADDED FeatureEvent indicating a new feature being created
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fireFeatureRemoved
public void fireFeatureRemoved(FeatureSource<?,?> source, Feature feature)
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fireFeatureEvent
public final void fireFeatureEvent(FeatureEvent event)
Used to issue a single FeatureEvent.If this content state is used for Transaction.AUTO_COMMIT the notification will be passed to all interested parties.
If not this event will be recored as part of a BatchFeatureEvent that will to be issued using issueBatchFeatureEvent()
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fireBatchFeatureEvent
public final void fireBatchFeatureEvent(boolean isCommit)
Notifies all waiting listeners that a commit has been issued; this notification is also sent to our
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flush
public void flush()
Clears cached state.This method does not affect any non-cached state. This method may be extended by subclasses, but not overiden.
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close
public void close()
Clears all state.Any resources that the state holds onto (like a database connection) should be closed or disposes when this method is called. This method may be extended by subclasses, but not overiden.
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copy
public ContentState copy()
Copies the state.Subclasses should override this method. Any mutable state objects should be cloned.
- Returns:
- A copy of the state.
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