de.umr.jepc.store

Interface EventStore

public interface EventStore

Abstraction from different event stores for JEPC.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all data from the database!
void	close() Closes the event store.
java.lang.Number[]	getAggregate(java.lang.String streamName, java.lang.String attribute, long startTime, long endTime) Returns the aggregates for the given stream and the given attribute within the given time interval.
java.util.Iterator<Event>	getBackwardsHistory(java.lang.String streamName) Returns the complete history of the given stream, beginning at the last inserted event and iterating backwards through the history.
long	getEventCount(java.lang.String streamName) Returns the number of events inserted into the given stream since the last reset.
long	getEventStoreCapacity() Returns the capacity of the event store.
java.util.Iterator<Event>	getFreshestHistory(java.lang.String streamName, long startTime) Returns the complete history of an event stream beginning from a user-defined instant of time ordered by time.
java.util.Iterator<Event>	getHistory(java.lang.String streamName) Returns the complete history of an event stream ordered by time(relation scan).
java.util.Iterator<Event>	getHistoryPoint(java.lang.String streamName, long timestamp) Returns all historical events of an event stream for a given point in time ordered by time (temporal point query).
java.util.Iterator<Event>	getHistoryRange(java.lang.String streamName, long startTime, long endTime) Returns all historical events of an event stream for a given range of time ordered by time (temporal range query).
Attribute[]	getLastCompiledSchema() Returns the last compiled schema of the event storem
long	getLastTimestamp(java.lang.String streamName) Returns the time stamp of the last inserted event.
java.util.Set<java.lang.String>	getRegisteredStreams() Returns all registered event streams.
Attribute[]	getSchema(java.lang.String streamName) Returns the schema for the given event stream.
long	getStreamSize(java.lang.String streamName) Returns the total size of the stream in bytes.
long	getTotalEventCount() Returns the total number of events inserted, counting from the last reset
void	open() Opens the event store.
void	pushEvent(java.lang.String streamName, java.lang.Object[] event) Pushes a new event into the event store.
void	pushEvent(java.lang.String streamName, java.lang.Object[] payload, long timestamp) Pushes a new event into the event store.
java.util.Iterator<Event>	query(java.lang.String sql) Queries the event store with the given SQL query.
java.util.Iterator<Event>	queryAttribute(java.lang.String streamName, java.lang.String attribute, java.lang.Comparable minKey, java.lang.Comparable maxKey) Queries the given attribute of the given stream and returns all events with the given attribute value between minKey and maxKey in temporal order.
java.util.Iterator<Event>	queryAttribute(java.lang.String streamName, java.lang.String attribute, java.lang.Comparable minKey, java.lang.Comparable maxKey, long startTime, long endTime) Queries the given attribute of the given stream and returns all events with the given attribute value between minKey and maxKey in the given time range in temporal order.
java.util.Iterator<Event>	queryAttributes(java.lang.String streamName, long startTime, long endTime, java.util.Map<java.lang.String,xxl.core.util.Pair<? extends java.lang.Number,? extends java.lang.Number>> attributeRanges) Queries the given attribute of the given stream and returns all events with the given attribute value between the given ranges in temporal order.
void	registerStream(java.lang.String streamName, Attribute[] schema) Registers a new event stream.
void	removeStream(java.lang.String streamName) Removes a stream and all stored events from the event store completely.
void	resumeStream(java.lang.String streamName) Resumes a stream after being suspended.
void	setEventStoreCapacity(int capacity, CapacityUnit capacityUnit) Sets the capacity of the event store.
boolean	supportsAggregates() Returns if the event store supports (materialized) aggregates, i.e.
void	suspendStream(java.lang.String streamName) Suspends a stream and frees all handlers on it.
void	unregisterStream(java.lang.String streamName) Unregisters a event stream.
void	updateEvent(java.lang.String streamName, java.lang.Object[] payload) Updates an event in the event store.

Method Detail

open

void open()

Opens the event store. This method should be called before using the event store.

close

void close()

Closes the event store.

clear

void clear()

Removes all data from the database!

registerStream

void registerStream(java.lang.String streamName,
                    Attribute[] schema)

Registers a new event stream.

Parameters:

streamName - the name of the event stream to register

schema - the schema of the event stream to register

getSchema

Attribute[] getSchema(java.lang.String streamName)

Returns the schema for the given event stream.

Parameters:

streamName - the name of the event stream

Returns:

the schema of the event stream, if a stream with the given name has been registered, null otherwise

unregisterStream

void unregisterStream(java.lang.String streamName)

Unregisters a event stream. In contrast to removeStream, this method preserves old events of a stream within the store.

Parameters:

streamName - the name of the event stream to unregister

suspendStream

void suspendStream(java.lang.String streamName)

Suspends a stream and frees all handlers on it. This method should be called, if the given stream will not be used for a considerable time. Before the given stream can be written to again, it has to be resumed.

Parameters:

streamName - The name of the stream to be suspended

resumeStream

void resumeStream(java.lang.String streamName)

Resumes a stream after being suspended. This method should be called to restore the state of the stream and all required file handlers.

Parameters:

streamName - The name of the stream to be resumed

removeStream

void removeStream(java.lang.String streamName)

Removes a stream and all stored events from the event store completely.

Parameters:

streamName - the name of the sevent stream to remove

getLastTimestamp

long getLastTimestamp(java.lang.String streamName)

Returns the time stamp of the last inserted event. If no event has been inserted yet, Long.MIN_VALUE is returned.

Parameters:

streamName - the name of the event stream

Returns:

the last timestamp

getTotalEventCount

long getTotalEventCount()

Returns the total number of events inserted, counting from the last reset

Returns:

the number of events inserted since the las reset

getEventCount

long getEventCount(java.lang.String streamName)

Returns the number of events inserted into the given stream since the last reset.

Parameters:

streamName - the name of the stream which event count should be reported

Returns:

the number of events inserted into the given stream since the last reset

getStreamSize

long getStreamSize(java.lang.String streamName)

Returns the total size of the stream in bytes. The size is reported "gross", without compression.

Parameters:

streamName - the name of the stream

Returns:

the size of the stream in bytes.

getRegisteredStreams

java.util.Set<java.lang.String> getRegisteredStreams()

Returns all registered event streams.

Returns:

the names of all registered event streams.

pushEvent

void pushEvent(java.lang.String streamName,
               java.lang.Object[] event)

Pushes a new event into the event store.

Parameters:

streamName - the corresponding event stream of the new event

event - the new event that is pushed into the event store

pushEvent

void pushEvent(java.lang.String streamName,
               java.lang.Object[] payload,
               long timestamp)

Pushes a new event into the event store.

Parameters:

streamName - the corresponding event stream of the new event

payload - the new event that is pushed into the event store

timestamp - the timestamp of the new event

updateEvent

void updateEvent(java.lang.String streamName,
                 java.lang.Object[] payload)

Updates an event in the event store. The corresponding event in the store is identified via the isKey property of the event stream`s schema attributes. Therefore, changes to values corresponding to key attributes lead to wrong/miss matches. If no key is defined, the timestamp is assumed to be the key.

Parameters:

streamName - the name of the event stream

payload - the new payload of the stream

getBackwardsHistory

java.util.Iterator<Event> getBackwardsHistory(java.lang.String streamName)

Returns the complete history of the given stream, beginning at the last inserted event and iterating backwards through the history.

Returns:

the complete history in reverse order

getFreshestHistory

java.util.Iterator<Event> getFreshestHistory(java.lang.String streamName,
                                             long startTime)

Returns the complete history of an event stream beginning from a user-defined instant of time ordered by time.

Parameters:

streamName - the event stream

startTime - the start instant of time

Returns:

the complete history of an event stream beginning from startTime

getHistory

java.util.Iterator<Event> getHistory(java.lang.String streamName)

Returns the complete history of an event stream ordered by time(relation scan).

Parameters:

streamName - the event stream

Returns:

the complete history of an event stream

getHistoryPoint

java.util.Iterator<Event> getHistoryPoint(java.lang.String streamName,
                                          long timestamp)

Returns all historical events of an event stream for a given point in time ordered by time (temporal point query).

Parameters:

streamName - the event stream

timestamp - the point in time

Returns:

all historical events of an event stream for the given point in time

getHistoryRange

java.util.Iterator<Event> getHistoryRange(java.lang.String streamName,
                                          long startTime,
                                          long endTime)

Returns all historical events of an event stream for a given range of time ordered by time (temporal range query).

Parameters:

streamName - the event stream

startTime - the beginning of the range

endTime - the end of the range

Returns:

all historical events of an event stream for the given range of time

queryAttributes

java.util.Iterator<Event> queryAttributes(java.lang.String streamName,
                                          long startTime,
                                          long endTime,
                                          java.util.Map<java.lang.String,xxl.core.util.Pair<? extends java.lang.Number,? extends java.lang.Number>> attributeRanges)
                                   throws java.lang.UnsupportedOperationException

Queries the given attribute of the given stream and returns all events with the given attribute value between the given ranges in temporal order. This method differs from queryAttribute that it accepts multiple ranges for each attribute

Parameters:

streamName - the event stream

startTime - the beginning of the range

endTime - the end of the range

attributeRanges - a map containing the attribute ranges for the attributes

Returns:

all historical events of the given event stream whose attribute values are within the given ranges

Throws:

java.lang.UnsupportedOperationException

getAggregate

java.lang.Number[] getAggregate(java.lang.String streamName,
                                java.lang.String attribute,
                                long startTime,
                                long endTime)
                         throws java.lang.UnsupportedOperationException

Returns the aggregates for the given stream and the given attribute within the given time interval. The aggregates have to be in the following order: sum, min, max, count, <optional values>

Parameters:

streamName - the name of the stream that should be queried

attribute - the attribute that should be aggregated

startTime - the start time

endTime - the end time

Returns:

all aggregates

Throws:

java.lang.UnsupportedOperationException

supportsAggregates

boolean supportsAggregates()

Returns if the event store supports (materialized) aggregates, i.e. getAggregate() is supported.

Returns:

true if this event store supports aggregates, false otherwise

queryAttribute

java.util.Iterator<Event> queryAttribute(java.lang.String streamName,
                                         java.lang.String attribute,
                                         java.lang.Comparable minKey,
                                         java.lang.Comparable maxKey)
                                  throws java.lang.UnsupportedOperationException

Queries the given attribute of the given stream and returns all events with the given attribute value between minKey and maxKey in temporal order.

Parameters:

streamName - the event stream

attribute - the attribute to query for

minKey - the minimum key value for the given attribute

maxKey - the maximum key value for the given attribute

Returns:

all historical events of an event stream whose value of the given attribute is within the range given by [minKey,maxKey]

Throws:

java.lang.UnsupportedOperationException

queryAttribute

java.util.Iterator<Event> queryAttribute(java.lang.String streamName,
                                         java.lang.String attribute,
                                         java.lang.Comparable minKey,
                                         java.lang.Comparable maxKey,
                                         long startTime,
                                         long endTime)
                                  throws java.lang.UnsupportedOperationException

Queries the given attribute of the given stream and returns all events with the given attribute value between minKey and maxKey in the given time range in temporal order.

Parameters:

streamName - the event stream

attribute - the attribute to query for

minKey - the minimum key value for the given attribute

maxKey - the maximum key value for the given attribute

startTime - the beginning of the range to query

endTime - the end of the range to query

Returns:

all historical events of an event stream in the given range of time whose value of the given attribute is within the range given by [minKey,maxKey]

Throws:

java.lang.UnsupportedOperationException

query

java.util.Iterator<Event> query(java.lang.String sql)

Queries the event store with the given SQL query. All events are delivered in the output schema of the query! Especially, the time stamps have to be included into the the projection to guarantee if required.

Parameters:

sql - the query as SQL query string

Returns:

all historical events that matches the query.

setEventStoreCapacity

void setEventStoreCapacity(int capacity,
                           CapacityUnit capacityUnit)

Sets the capacity of the event store.

Parameters:

capacity - the capacity of the event store

capacityUnit - the unit that specifies how to interpret the capacity

getEventStoreCapacity

long getEventStoreCapacity()

Returns the capacity of the event store.

Returns:

the maximum capacity of the event store.

getLastCompiledSchema

Attribute[] getLastCompiledSchema()

Returns the last compiled schema of the event storem

Returns:

the last compiled schema