streams.esper

Class Query

java.lang.Object

stream.AbstractProcessor

streams.esper.Query

All Implemented Interfaces:

stream.Configurable, stream.Processor, stream.StatefulProcessor

public class Query
extends stream.AbstractProcessor
implements stream.Configurable

Streams-Esper Query objects represent Esper statements. They are Streams Processor objects and refer to an EsperEngine.

The BodyText of an XML configuration element represents the actual Esper statement. References to the Esper engine are provided via an attribute.

Note that the Esper types for this query must be delcared to the Esper engine this Query object references.

Since:

0.3.0

Version:

0.3.0

Author:

Thomas Scharrenbach

See Also:

EsperEngine

Field Summary

Fields inherited from class stream.AbstractProcessor

context

Constructor Summary

Constructors

Constructor and Description
Query()

Method Summary

Methods

Modifier and Type	Method and Description
void	configure(Element document)
void	finish()
String	getEngine()
protected EsperEngine	getEsperEngine()
String	getInputType()
String	getName()
stream.io.Sink[]	getOutput()
String	getQuery()
void	init(stream.ProcessContext ctx) Fetches the Esper engine from the EsperEngine's registry and adds this query to the engine.
boolean	isForward()
Boolean	isRemoveBackticks()
stream.Data	process(stream.Data input) Hand over the Data item to the referenced EsperEngine.
void	setEngine(String engine)
protected void	setEsperEngine(EsperEngine esperEngine)
void	setForward(Boolean forward)
void	setInputType(String inputType)
void	setName(String name)
void	setOutput(stream.io.Sink[] output)
void	setQuery(stream.annotations.BodyContent esperQuery)
void	setRemoveBackticks(Boolean removeBackticks)

Methods inherited from class stream.AbstractProcessor

resetState

Methods inherited from class java.lang.Object

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

Constructor Detail

Query

public Query()

Method Detail

process

public stream.Data process(stream.Data input)

Hand over the Data item to the referenced EsperEngine.

Specified by:

process in interface stream.Processor

Since:

0.3.0

init

public void init(stream.ProcessContext ctx)
          throws Exception

Fetches the Esper engine from the EsperEngine's registry and adds this query to the engine.

Specified by:

init in interface stream.StatefulProcessor

Overrides:

init in class stream.AbstractProcessor

Throws:

NullPointerException - if no Esper engine was configured.

Exception

Since:

0.3.0

finish

public void finish()
            throws Exception

Specified by:

finish in interface stream.StatefulProcessor

Overrides:

finish in class stream.AbstractProcessor

Throws:

Exception

getQuery

public String getQuery()

Since:

0.3.0

getEsperEngine

protected EsperEngine getEsperEngine()

Returns:

the esperEngine

setEsperEngine

protected void setEsperEngine(EsperEngine esperEngine)

Parameters:

esperEngine - the esperEngine to set

setQuery

public void setQuery(stream.annotations.BodyContent esperQuery)

Throws:

IllegalArgumentException - if the query has already been set.

Since:

0.3.0

setOutput

@Parameter
public void setOutput(stream.io.Sink[] output)

Throws:

IllegalArgumentException - if the sinks have already been set.

Since:

0.3.0

getOutput

public stream.io.Sink[] getOutput()

Since:

0.3.0

setEngine

@Parameter(defaultValue="default",
           required=false)
public void setEngine(String engine)

Throws:

IllegalArgumentException - if the engine id has already been set.

Since:

0.3.0

getEngine

public String getEngine()

Since:

0.3.0

setName

@Parameter(required=false,
           description="The optional name for the Esper statement.")
public void setName(String name)

Since:

0.3.0

getName

public String getName()

Since:

0.3.0

setRemoveBackticks

@Parameter(required=false,
           defaultValue="false",
           description="Flag whether to remove backticks from the keys.")
public void setRemoveBackticks(Boolean removeBackticks)

Since:

0.3.0

isRemoveBackticks

public Boolean isRemoveBackticks()

Since:

0.3.0

setInputType

@Parameter(required=false,
           defaultValue="",
           description="If this parameter is set we assume that events input to this query are of a Map type.")
public void setInputType(String inputType)

Since:

0.3.0

getInputType

public String getInputType()

Since:

0.3.0

setForward

@Parameter(defaultValue="false",
           name="forward-input",
           description="Flag that inicates whether a data item should be forwarded to later processors. ")
public void setForward(Boolean forward)

isForward

public boolean isForward()

configure

public void configure(Element document)

Specified by:

configure in interface stream.Configurable

See Also:

Configurable.configure(org.w3c.dom.Element)