QueryRecorder (Java API Reference for Oracle? Coherence Community Edition)

java.lang.Object
- com.tangosol.util.aggregator.QueryRecorder<K,V>

Type Parameters:

K - the type of the Map entry keys

V - the type of the Map entry values

All Implemented Interfaces:

ExternalizableLite, PortableObject, InvocableMap.EntryAggregator<K,V,QueryRecord>, InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>, Serializable
```
public class QueryRecorder<K,V>
extends Object
implements InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>, ExternalizableLite, PortableObject
```
This aggregator is used to produce a QueryRecord object that contains an estimated or actual cost of the query execution for a given filter.
For example, the following code will print a QueryRecord, containing the estimated query cost and corresponding execution steps.
```
   QueryRecorder agent  = new QueryRecorder(RecordType.EXPLAIN);
   QueryRecord   record = (QueryRecord) cache.aggregate(filter, agent);
   System.out.println(record);
 
```
Author:

tb 2011.05.26

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`QueryRecorder.RecordType` RecordType enum specifies whether the `QueryRecorder` should be used to produce a `QueryRecord` object that contains an estimated or an actual cost of the query execution.

Field Summary
- Fields inherited from interface com.tangosol.util.InvocableMap.StreamingAggregator
  ALLOW_INCONSISTENCIES, BY_MEMBER, BY_PARTITION, PARALLEL, PRESENT_ONLY, RETAINS_ENTRIES, SERIAL

Constructor Summary

Constructors
Constructor and Description
`QueryRecorder()` Default constructor (necessary for the ExternalizableLite interface).
`QueryRecorder(QueryRecorder.RecordType type)` Construct a QueryRecorder.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`accumulate(InvocableMap.Entry<? extends K,? extends V> entry)` Accumulate one entry into the result.
`boolean`	`accumulate(Streamer<? extends InvocableMap.Entry<? extends K,? extends V>> streamer)` Accumulate multiple entries into the result.
`QueryRecord`	`aggregate(Set<? extends InvocableMap.Entry<? extends K,? extends V>> setEntries)` Process a set of InvocableMap.Entry objects in order to produce an aggregated result.
`int`	`characteristics()` A bit mask representing the set of characteristics of this aggregator.
`boolean`	`combine(QueryRecord.PartialResult partialResult)` Merge another partial result into the result.
`QueryRecord`	`finalizeResult()` Return the final result of the aggregation.
`QueryRecord.PartialResult`	`getPartialResult()` Return the partial result of the aggregation.
`QueryRecorder.RecordType`	`getType()` Get the record type for this query recorder.
`void`	`readExternal(DataInput in)` Restore the contents of this object by loading the object's state from the passed DataInput object.
`void`	`readExternal(PofReader in)` Restore the contents of a user type instance by reading its state using the specified PofReader object.
`InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>`	`supply()` Create a new instance of this aggregator.
`void`	`writeExternal(DataOutput out)` Save the contents of this object by storing the object's state into the passed DataOutput object.
`void`	`writeExternal(PofWriter out)` Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.tangosol.util.InvocableMap.StreamingAggregator
isAllowInconsistencies, isByMember, isByPartition, isParallel, isPresentOnly, isRetainsEntries, isSerial

- Constructor Detail
  - QueryRecorder
```
public QueryRecorder()
```
    Default constructor (necessary for the ExternalizableLite interface).
  - QueryRecorder
```
public QueryRecorder(QueryRecorder.RecordType type)
```
    Construct a QueryRecorder.
    
    Parameters:
    
    type - the type for this aggregator
- Method Detail
  - getType
```
public QueryRecorder.RecordType getType()
```
    Get the record type for this query recorder.
    
    Returns:
    
    the record type enum
  - aggregate
```
public QueryRecord aggregate(Set<? extends InvocableMap.Entry<? extends K,? extends V>> setEntries)
```
    Process a set of InvocableMap.Entry objects in order to produce an aggregated result.
    
    Specified by:
    
    aggregate in interface InvocableMap.EntryAggregator<K,V,QueryRecord>
    
    Specified by:
    
    aggregate in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Parameters:
    
    setEntries - a Set of read-only InvocableMap.Entry objects to aggregate
    
    Returns:
    
    the aggregated result from processing the entries
  - supply
```
public InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord> supply()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Create a new instance of this aggregator.
    
    Specified by:
    
    supply in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Returns:
    
    a StreamAggregator
  - accumulate
```
public boolean accumulate(Streamer<? extends InvocableMap.Entry<? extends K,? extends V>> streamer)
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Accumulate multiple entries into the result.
    Important note: The default implementation of this method provides necessary logic for aggregation short-circuiting and should rarely (if ever) be overridden by the custom aggregator implementation.
    
    Specified by:
    
    accumulate in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Parameters:
    
    streamer - a Streamer that can be used to iterate over entries to add
    
    Returns:
    
    true to continue the aggregation, and false to signal to the caller that the result is ready and the aggregation can be short-circuited
  - accumulate
```
public boolean accumulate(InvocableMap.Entry<? extends K,? extends V> entry)
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Accumulate one entry into the result.
    
    Specified by:
    
    accumulate in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Parameters:
    
    entry - the entry to accumulate into the aggregation result
    
    Returns:
    
    true to continue the aggregation, and false to signal to the caller that the result is ready and the aggregation can be short-circuited
  - combine
```
public boolean combine(QueryRecord.PartialResult partialResult)
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Merge another partial result into the result.
    
    Specified by:
    
    combine in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Parameters:
    
    partialResult - the partial result to merge
    
    Returns:
    
    true to continue the aggregation, and false to signal to the caller that the result is ready and the aggregation can be short-circuited
  - getPartialResult
```
public QueryRecord.PartialResult getPartialResult()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Return the partial result of the aggregation.
    
    Specified by:
    
    getPartialResult in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Returns:
    
    the partial result of the aggregation
  - finalizeResult
```
public QueryRecord finalizeResult()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Return the final result of the aggregation.
    
    Specified by:
    
    finalizeResult in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Returns:
    
    the final result of the aggregation
  - characteristics
```
public int characteristics()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    A bit mask representing the set of characteristics of this aggregator.
    Be default, characteristics are a combination of InvocableMap.StreamingAggregator.PARALLEL and InvocableMap.StreamingAggregator.RETAINS_ENTRIES, which is sub-optimal and should be overridden by the aggregator implementation if the aggregator does not need to retain entries (which is often the case).
    
    Specified by:
    
    characteristics in interface InvocableMap.StreamingAggregator<K,V,QueryRecord.PartialResult,QueryRecord>
    
    Returns:
    
    a bit mask representing the set of characteristics of this aggregator
    
    See Also:
    
    InvocableMap.StreamingAggregator.PARALLEL, InvocableMap.StreamingAggregator.SERIAL, InvocableMap.StreamingAggregator.BY_MEMBER, InvocableMap.StreamingAggregator.BY_PARTITION, InvocableMap.StreamingAggregator.RETAINS_ENTRIES, InvocableMap.StreamingAggregator.PRESENT_ONLY
  - readExternal
```
public void readExternal(DataInput in)
                  throws IOException
```
    Restore the contents of this object by loading the object's state from the passed DataInput object.
    
    Specified by:
    
    readExternal in interface ExternalizableLite
    
    Parameters:
    
    in - the DataInput stream to read data from in order to restore the state of this object
    
    Throws:
    
    IOException - if an I/O exception occurs
    
    NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into
  - writeExternal
```
public void writeExternal(DataOutput out)
                   throws IOException
```
    Save the contents of this object by storing the object's state into the passed DataOutput object.
    
    Specified by:
    
    writeExternal in interface ExternalizableLite
    
    Parameters:
    
    out - the DataOutput stream to write the state of this object to
    
    Throws:
    
    IOException - if an I/O exception occurs
  - readExternal
```
public void readExternal(PofReader in)
                  throws IOException
```
    Restore the contents of a user type instance by reading its state using the specified PofReader object.
    
    Specified by:
    
    readExternal in interface PortableObject
    
    Parameters:
    
    in - the PofReader from which to read the object's state
    
    Throws:
    
    IOException - if an I/O error occurs
  - writeExternal
```
public void writeExternal(PofWriter out)
                   throws IOException
```
    Save the contents of a POF user type instance by writing its state using the specified PofWriter object.
    
    Specified by:
    
    writeExternal in interface PortableObject
    
    Parameters:
    
    out - the PofWriter to which to write the object's state
    
    Throws:
    
    IOException - if an I/O error occurs

Class QueryRecorder<K,V>

Nested Class Summary

Field Summary

Fields inherited from interface com.tangosol.util.InvocableMap.StreamingAggregator

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface com.tangosol.util.InvocableMap.StreamingAggregator

Constructor Detail

QueryRecorder

QueryRecorder

Method Detail

getType

aggregate

supply

accumulate

accumulate

combine

getPartialResult

finalizeResult

characteristics

readExternal

writeExternal

readExternal

writeExternal