com.couchbase.lite

Class LiveQuery

java.lang.Object

com.couchbase.lite.Query

com.couchbase.lite.LiveQuery

All Implemented Interfaces:

Database.ChangeListener

public final class LiveQuery
extends Query
implements Database.ChangeListener

A Query subclass that automatically refreshes the result rows every time the database changes. All you need to do is use add a listener to observe changes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LiveQuery.ChangeEvent The type of event raised when a LiveQuery result set changes.
static interface	LiveQuery.ChangeListener A delegate that can be used to listen for LiveQuery result set changes.

Nested classes/interfaces inherited from class com.couchbase.lite.Query

Query.AllDocsMode, Query.IndexUpdateMode, Query.QueryCompleteListener

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.concurrent.Future	queryFuture If a query is running and the user calls stop() on this query, the future will be used in order to cancel the query in progress.
protected java.util.concurrent.Future	rerunUpdateFuture If the update() method is called while a query is in progress, once it is finished it will be scheduled to re-run update().

Method Summary

Modifier and Type	Method and Description
void	addChangeListener(LiveQuery.ChangeListener changeListener) Add a change listener to be notified when the live query result set changes.
void	changed(Database.ChangeEvent event)
java.lang.Throwable	getLastError() Returns the last error, if any, that occured while executing the Query, otherwise null.
QueryEnumerator	getRows() Gets the results of the Query.
void	queryOptionsChanged()
void	removeChangeListener(LiveQuery.ChangeListener changeListener) Remove previously added change listener
QueryEnumerator	run() Sends the query to the server and returns an enumerator over the result rows (Synchronous).
void	start() Starts observing database changes.
void	stop() Stops observing database changes.
void	waitForRows() Blocks until the intial async query finishes.

Methods inherited from class com.couchbase.lite.Query

finalize, getAllDocsMode, getDatabase, getEndKey, getEndKeyDocId, getGroupLevel, getIndexUpdateMode, getKeys, getLimit, getPostFilter, getPrefixMatchLevel, getSkip, getStartKey, getStartKeyDocId, getView, isDescending, isInclusiveEnd, isInclusiveStart, isMapOnly, runAsync, setAllDocsMode, setDescending, setEndKey, setEndKeyDocId, setGroupLevel, setIncludeDeleted, setInclusiveEnd, setInclusiveStart, setIndexUpdateMode, setKeys, setLimit, setMapOnly, setPostFilter, setPrefetch, setPrefixMatchLevel, setSkip, setStartKey, setStartKeyDocId, shouldIncludeDeleted, shouldPrefetch, toLiveQuery

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

queryFuture

protected java.util.concurrent.Future queryFuture

If a query is running and the user calls stop() on this query, the future will be used in order to cancel the query in progress.

rerunUpdateFuture

protected java.util.concurrent.Future rerunUpdateFuture

If the update() method is called while a query is in progress, once it is finished it will be scheduled to re-run update(). This tracks the future related to that scheduled task.

Method Detail

run

public QueryEnumerator run()
                    throws CouchbaseLiteException

Sends the query to the server and returns an enumerator over the result rows (Synchronous). Note: In a LiveQuery you should consider adding a ChangeListener and calling start() instead.

Overrides:

run in class Query

Throws:

CouchbaseLiteException

getLastError

public java.lang.Throwable getLastError()

Returns the last error, if any, that occured while executing the Query, otherwise null.

start

public void start()

Starts observing database changes. The .rows property will now update automatically. (You usually don't need to call this yourself, since calling getRows() will start it for you

stop

public void stop()

Stops observing database changes. Calling start() or rows() will restart it.

waitForRows

public void waitForRows()
                 throws CouchbaseLiteException

Blocks until the intial async query finishes. After this call either .rows or .error will be non-nil. TODO: It seems that implementation of waitForRows() is not correct. Should fix this!!! https://github.com/couchbase/couchbase-lite-java-core/issues/647

Throws:

CouchbaseLiteException

getRows

public QueryEnumerator getRows()

Gets the results of the Query. The value will be null until the initial Query completes.

addChangeListener

public void addChangeListener(LiveQuery.ChangeListener changeListener)

Add a change listener to be notified when the live query result set changes.

removeChangeListener

public void removeChangeListener(LiveQuery.ChangeListener changeListener)

Remove previously added change listener

changed

public void changed(Database.ChangeEvent event)

Specified by:

changed in interface Database.ChangeListener

queryOptionsChanged

public void queryOptionsChanged()