com.netflix.hollow.core.index

Class HollowPrimaryKeyIndex

java.lang.Object

com.netflix.hollow.core.index.HollowPrimaryKeyIndex

All Implemented Interfaces:

HollowTypeStateListener

public class HollowPrimaryKeyIndex
extends java.lang.Object
implements HollowTypeStateListener

A HollowPrimaryKeyIndex is the go-to mechanism for indexing and querying data in a Hollow blob.

A primary key index can be used to index and query a type by a PrimaryKey. The provided PrimaryKey does not have to be the same as declared as the default in the data model. This class is not safe to use with object longevity if the index is not being updated for each delta. The internal implementation of this class uses the type state retrieved through the schema. That resutls in certain operations always being performed against the current version. As such, this class is only valid for up to 2 updates. If you need an index that will survive 2 or more deltas (without being updated), then use HollowUniqueKeyIndex or HollowHashIndex.

Constructor Summary

Constructors

Constructor and Description
HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine, ArraySegmentRecycler memoryRecycler, java.lang.String type, java.lang.String... fieldPaths)
HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine, PrimaryKey primaryKey)
HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine, PrimaryKey primaryKey, ArraySegmentRecycler memoryRecycler)
HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine, PrimaryKey primaryKey, ArraySegmentRecycler memoryRecycler, java.util.BitSet specificOrdinalsToIndex) This initializer can be used to create a HollowPrimaryKeyIndex which will only index a subset of the records in the specified type.
HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine, java.lang.String type, java.lang.String... fieldPaths)

Method Summary

Modifier and Type	Method and Description
void	addedOrdinal(int ordinal) Called once for each record which is added to the registered type.
void	beginUpdate() Called immediately before a delta update is applied to the state engine
boolean	containsDuplicates()
void	destroy()
void	detachFromDeltaUpdates() Once called, this HollowPrimaryKeyIndex will no longer be kept up-to-date when deltas are applied to the indexed state engine.
void	endUpdate() Called immediately after a delta update is applied to the state engine.
java.util.Collection<java.lang.Object[]>	getDuplicateKeys()
java.util.List<HollowObjectSchema.FieldType>	getFieldTypes()
int	getMatchingOrdinal(java.lang.Object... keys) Query an index with four or more specified fields.
int	getMatchingOrdinal(java.lang.Object key) Query an index with a single specified field.
int	getMatchingOrdinal(java.lang.Object key1, java.lang.Object key2) Query an index with two specified fields.
int	getMatchingOrdinal(java.lang.Object key1, java.lang.Object key2, java.lang.Object key3) Query an index with three specified fields.
PrimaryKey	getPrimaryKey()
java.lang.Object[]	getRecordKey(int ordinal)
HollowObjectTypeReadState	getTypeState()
void	listenForDeltaUpdates() Once called, this HollowPrimaryKeyIndex will be kept up-to-date when deltas are applied to the indexed state engine.
void	removedOrdinal(int ordinal) Called once for each record which is removed from the registered type.

Methods inherited from class java.lang.Object

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

Constructor Detail

HollowPrimaryKeyIndex

public HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine,
                             java.lang.String type,
                             java.lang.String... fieldPaths)

HollowPrimaryKeyIndex

public HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine,
                             PrimaryKey primaryKey)

HollowPrimaryKeyIndex

public HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine,
                             ArraySegmentRecycler memoryRecycler,
                             java.lang.String type,
                             java.lang.String... fieldPaths)

HollowPrimaryKeyIndex

public HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine,
                             PrimaryKey primaryKey,
                             ArraySegmentRecycler memoryRecycler)

HollowPrimaryKeyIndex

public HollowPrimaryKeyIndex(HollowReadStateEngine stateEngine,
                             PrimaryKey primaryKey,
                             ArraySegmentRecycler memoryRecycler,
                             java.util.BitSet specificOrdinalsToIndex)

This initializer can be used to create a HollowPrimaryKeyIndex which will only index a subset of the records in the specified type.

Parameters:

stateEngine - the read state engine

primaryKey - the primary key

memoryRecycler - the memory recycler

specificOrdinalsToIndex - the bit set

Method Detail

listenForDeltaUpdates

public void listenForDeltaUpdates()

Once called, this HollowPrimaryKeyIndex will be kept up-to-date when deltas are applied to the indexed state engine.

This method should be called before any subsequent deltas occur after the index is created.

In order to prevent memory leaks, if this method is called and the index is no longer needed, call detachFromDeltaUpdates() before discarding the index.

Note that this index does not listen on snapshot update. If a snapshot update occurs this index will NOT return the latest data in the consumer. Callers must detach this index instance and initialize a new one on snapshot update, or disable double snapshot update for the consumer altogether.

detachFromDeltaUpdates

public void detachFromDeltaUpdates()

Once called, this HollowPrimaryKeyIndex will no longer be kept up-to-date when deltas are applied to the indexed state engine.

Call this method before discarding indexes which are currently listening for delta updates.

getTypeState

public HollowObjectTypeReadState getTypeState()

getPrimaryKey

public PrimaryKey getPrimaryKey()

getFieldTypes

public java.util.List<HollowObjectSchema.FieldType> getFieldTypes()

getMatchingOrdinal

public int getMatchingOrdinal(java.lang.Object key)

Query an index with a single specified field. The returned value with be the ordinal of the matching record.

Use a generated API or the Generic Object API to use the returned ordinal.

Parameters:

key - the field key

Returns:

the matching ordinal for the key, otherwise -1 if the key is not present

getMatchingOrdinal

public int getMatchingOrdinal(java.lang.Object key1,
                              java.lang.Object key2)

Query an index with two specified fields. The returned value with be the ordinal of the matching record.

Use a generated API or the Generic Object API to use the returned ordinal.

Parameters:

key1 - the first field key

key2 - the second field key

Returns:

the matching ordinal for the two keys, otherwise -1 if the key is not present

getMatchingOrdinal

public int getMatchingOrdinal(java.lang.Object key1,
                              java.lang.Object key2,
                              java.lang.Object key3)

Query an index with three specified fields. The returned value with be the ordinal of the matching record.

Use a generated API or the Generic Object API to use the returned ordinal.

Parameters:

key1 - the first field key

key2 - the second field key

key3 - the third field key

Returns:

the matching ordinal for the three keys, otherwise -1 if the key is not present

getMatchingOrdinal

public int getMatchingOrdinal(java.lang.Object... keys)

Query an index with four or more specified fields. The returned value with be the ordinal of the matching record.

Use a generated API or the Generic Object API to use the returned ordinal.

Parameters:

keys - the field keys

Returns:

the matching ordinal for the keys, otherwise -1 if the key is not present

containsDuplicates

public boolean containsDuplicates()

Returns:

whether or not this index contains duplicate records (two or more records mapping to a single primary key).

getDuplicateKeys

public java.util.Collection<java.lang.Object[]> getDuplicateKeys()

Returns:

any keys which are mapped to two or more records.

beginUpdate

public void beginUpdate()

Description copied from interface: HollowTypeStateListener

Called immediately before a delta update is applied to the state engine

Specified by:

beginUpdate in interface HollowTypeStateListener

addedOrdinal

public void addedOrdinal(int ordinal)

Description copied from interface: HollowTypeStateListener

Called once for each record which is added to the registered type.

Specified by:

addedOrdinal in interface HollowTypeStateListener

Parameters:

ordinal - the ordinal of an object that was added

removedOrdinal

public void removedOrdinal(int ordinal)

Description copied from interface: HollowTypeStateListener

Called once for each record which is removed from the registered type.

Specified by:

removedOrdinal in interface HollowTypeStateListener

Parameters:

ordinal - the ordinal of an object that was removed

endUpdate

public void endUpdate()

Description copied from interface: HollowTypeStateListener

Called immediately after a delta update is applied to the state engine.

Specified by:

endUpdate in interface HollowTypeStateListener

destroy

public void destroy()

getRecordKey

public java.lang.Object[] getRecordKey(int ordinal)