GroupAggregator (Oracle® Coherence Java API Reference)

java.lang.Object
- com.tangosol.util.Base
- - com.tangosol.util.BitHelper
  - - com.tangosol.util.ExternalizableHelper
    - - com.tangosol.util.aggregator.GroupAggregator<K,V,T,E,R>

Type Parameters:

K - the type of the Map entry keys

V - the type of the Map entry values

T - the type of the value to extract from

E - the type of the extracted value

R - the type of the group aggregator result

All Implemented Interfaces:

ExternalizableLite, PortableObject, InvocableMap.EntryAggregator<K,V,Map<E,R>>, InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>, Serializable

Direct Known Subclasses:

GroupAggregator.Parallel
```
public class GroupAggregator<K,V,T,E,R>
extends ExternalizableHelper
implements InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>, ExternalizableLite, PortableObject
```
The GroupAggregator provides an ability to split a subset of entries in an InvocableMap into a collection of non-intersecting subsets and then aggregate them separately and independently. The splitting (grouping) is performed using the results of the underlying ValueExtractor in such a way that two entries will belong to the same group if and only if the result of the corresponding extract call produces the same value or tuple (list of values). After the entries are split into the groups, the underlying aggregator is applied separately to each group. The result of the aggregation by the GroupAggregator is a Map that has distinct values (or tuples) as keys and results of the individual aggregation as values. Additionally, those results could be further reduced using an optional Filter object.
Informally speaking, this aggregator is analogous to the SQL "group by" and "having" clauses. Note that the "having" Filter is applied independently on each server against the partial aggregation results; this generally implies that data affinity is required to ensure that all required data used to generate a given result exists within a single cache partition. In other words, the "group by" predicate should not span multiple partitions if the "having" clause is used.

The GroupAggregator is somewhat similar to the DistinctValues aggregator, which returns back a list of distinct values (tuples) without performing any additional aggregation work.

Unlike many other concrete EntryAggregator implementations that are constructed directly, instances of GroupAggregator should only be created using one of the factory methods: createInstance(extractor, aggregator), createInstance(extractor, aggregator, filter), createInstance(sMethod, aggregator) createInstance(sMethod, aggregator, filter)

Since:

Coherence 3.2

Author:

gg 2006.02.15, as 2014.11.09

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class GroupAggregator.Parallel<K,V,T,E,R>
Deprecated.
As of Coherence 12.2.1. Use GroupAggregator instead.
- Nested classes/interfaces inherited from class com.tangosol.util.ExternalizableHelper
  ExternalizableHelper.DecoratedMultiBufferReadBuffer, ExternalizableHelper.DefaultObjectStreamFactory, ExternalizableHelper.FormatAwareCompressor, ExternalizableHelper.IntDecoratedObject, ExternalizableHelper.Shielded, ExternalizableHelper.ShieldedDataOutputStream, ExternalizableHelper.ShieldedInputStream, ExternalizableHelper.ShieldedObjectOutputStream, ExternalizableHelper.ShieldedOutputStream, ExternalizableHelper.SimpleXmlBeanClassCache, ExternalizableHelper.Stats, ExternalizableHelper.XmlBeanClassCache
- Nested classes/interfaces inherited from class com.tangosol.util.Base
  Base.LoggingWriter, Base.StackFrame

Nested Classes
Modifier and Type	Class and Description
`static class`	`GroupAggregator.Parallel<K,V,T,E,R>` Deprecated. As of Coherence 12.2.1. Use GroupAggregator instead.

Field Summary

Fields
Modifier and Type	Field and Description
`protected InvocableMap.EntryAggregator<? super K,? super V,R>`	`m_aggregator` The underlying EntryAggregator.
`protected ValueExtractor<? super T,? extends E>`	`m_extractor` The underlying ValueExtractor.
`protected Filter`	`m_filter` The Filter object representing the "having" clause of this "group by" aggregator.
`protected boolean`	`m_fInit` Flag specifying whether this aggregator has been initialized.
`protected boolean`	`m_fParallel` Flag specifying whether parallel optimizations can be used.
`protected boolean`	`m_fStreaming` Flag specifying whether streaming optimizations can be used.
`protected Map<E,Object>`	`m_mapResults` A map of partial results to aggregate.

Fields inherited from class com.tangosol.util.ExternalizableHelper
CONVERTER_FROM_BINARY, CONVERTER_STRIP_INTDECO, CONVERTER_TO_BINARY, DECO_APP_1, DECO_APP_2, DECO_APP_3, DECO_CUSTOM, DECO_EXPIRY, DECO_ID_MAX, DECO_ID_MIN, DECO_JCACHE, DECO_JCACHE_SYNTHETIC, DECO_MEMCACHED, DECO_PUSHREP, DECO_QUEUE_METADATA, DECO_RSVD_1, DECO_RSVD_2, DECO_STORE, DECO_TOPLINK, DECO_TX, DECO_VALUE, DECO_WLS, EMPTY_BINARY_ARRAY, FMT_B_ARRAY, FMT_BIN_DECO, FMT_BIN_EXT_DECO, FMT_BINARY, FMT_BOOLEAN, FMT_BYTE, FMT_DECIMAL, FMT_DOUBLE, FMT_EXT, FMT_FLOAT, FMT_IDO, FMT_INT, FMT_INTEGER, FMT_LONG, FMT_NONE, FMT_NULL, FMT_OBJ_EXT, FMT_OBJ_SER, FMT_OPT, FMT_OPT_DOUBLE, FMT_OPT_INT, FMT_OPT_LONG, FMT_SHORT, FMT_STRING, FMT_UNKNOWN, FMT_XML_BEAN, FMT_XML_SER, FORCE_RESOLVING_STREAMS, MAX_DECO_HEADER_BYTES, PROPERTY_CONFIG, s_streamfactory, TRINT_DOMAIN_SPAN, TRINT_MAX_VALUE, TRINT_MAX_VARIANCE, USE_POF_STREAMS, USE_XMLBEAN_CLASS_CACHE, XMLBEAN_CLASS_CACHE

Fields inherited from class com.tangosol.util.Base
LOG_ALWAYS, LOG_DEBUG, LOG_ERR, LOG_INFO, LOG_MAX, LOG_MIN, LOG_QUIET, LOG_WARN, POWER_0, POWER_G, POWER_K, POWER_M, POWER_T, UNIT_D, UNIT_H, UNIT_M, UNIT_MS, UNIT_NS, UNIT_S, UNIT_US

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

Constructor Summary

Constructors
Modifier	Constructor and Description
	`GroupAggregator()` Default constructor (necessary for the ExternalizableLite interface).
`protected`	`GroupAggregator(ValueExtractor<? super T,? extends E> extractor, InvocableMap.EntryAggregator<? super K,? super V,R> aggregator, Filter filter)` Construct a GroupAggregator based on a specified ValueExtractor and underlying EntryAggregator.

Method Summary

All Methods Static 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.
`int`	`characteristics()` A bit mask representing the set of characteristics of this aggregator.
`boolean`	`combine(Map<E,Object> partialResult)` Merge another partial result into the result.
`static <K,V,R> GroupAggregator<K,V,Object,Object,R>`	`createInstance(String sMethod, InvocableMap.EntryAggregator<K,V,R> aggregator)` Create an instance of GroupAggregator based on a specified method name(s) and an `EntryAggregator`.
`static <K,V,R> GroupAggregator<K,V,Object,Object,R>`	`createInstance(String sMethod, InvocableMap.EntryAggregator<K,V,R> aggregator, Filter filter)` Create an instance of GroupAggregator based on a specified method name(s), an `EntryAggregator` and a result evaluation filter.
`static <K,V,T,E,R> GroupAggregator<K,V,T,E,R>`	`createInstance(ValueExtractor<? super T,? extends E> extractor, InvocableMap.EntryAggregator<? super K,? super V,R> aggregator, Filter filter)` Create an instance of GroupAggregator based on a specified extractor and an `EntryAggregator` and a result evaluation filter.
`static <K,V,T,E,R> GroupAggregator<K,V,T,E,R>`	`createInstance(ValueExtractor<? super T,? extends E> extractor, InvocableMap.EntryAggregator<K,V,R> aggregator)` Create an instance of GroupAggregator based on a specified extractor and an `EntryAggregator`.
`protected void`	`ensureInitialized()` Ensure that this aggregator is initialized.
`boolean`	`equals(Object o)` Compare the GroupAggregator with another object to determine equality.
`Map<E,R>`	`finalizeResult()` Return the final result of the aggregation.
`InvocableMap.EntryAggregator<? super K,? super V,R>`	`getAggregator()` Obtain the underlying EntryAggregator.
`ValueExtractor<?,? extends E>`	`getExtractor()` Obtain the underlying ValueExtractor.
`Map<E,Object>`	`getPartialResult()` Return the partial result of the aggregation.
`int`	`hashCode()` Determine a hash value for the GroupAggregator object according to the general `Object.hashCode()` contract.
`protected boolean`	`isDelegateParallel()` Return <c>true</c> if the underlying aggregator is a ParallelAwareAggregator.
`protected boolean`	`isDelegateStreaming()` Return <c>true</c> if the underlying aggregator is a StreamingAggregator.
`protected InvocableMap.ParallelAwareAggregator<? super K,? super V,Object,R>`	`parallel(InvocableMap.EntryAggregator<? super K,? super V,R> aggregator)` Convert the specified aggregator to ParallelAwareAggregator.
`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.
`protected InvocableMap.StreamingAggregator<? super K,? super V,Object,R>`	`streaming(InvocableMap.EntryAggregator<? super K,? super V,R> aggregator)` Convert the specified aggregator to StreamingAggregator.
`InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>`	`supply()` Create a new instance of this aggregator.
`protected static <T> BinaryOperator<T>`	`throwingMerger()`
`String`	`toString()` Return a human-readable description for this GroupAggregator.
`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 com.tangosol.util.ExternalizableHelper
asBinary, calculatePackedLength, calculatePackedLength, convertUTF, decodeExpiry, decorate, decorate, decorate, decorate, decorate, decorateBinary, encodeExpiry, ensureSerializer, extractIntDecoration, fromBinary, fromBinary, fromBinary, fromByteArray, fromByteArray, getDecoration, getDecoration, getDecorations, getDeltaCompressor, getInputStream, getNewObjectInput, getObjectInput, getObjectOutput, getObjectStreamFactory, getOutputStream, getShieldedOutputStream, getStreamFormat, getUndecorated, getUndecorated, isDecorated, isDecorated, isIntDecorated, isIntDecorated, isResolving, isSerializable, isSerializerCompatible, isVersionCompatible, isVersionCompatible, loadClass, loadResource, main, makeTrint, readBigDecimal, readBigInteger, readBooleanArray, readByteArray, readCollection, readDate, readDoubleArray, readExternalizableLite, readExternalizableLite, readFloatArray, readInt, readInt, readIntArray2d, readLong, readLong, readMap, readMap, readObject, readObject, readSafeUTF, readSafeUTF, readSerializable, readSerializable, readStringArray, readTime, readTimestamp, readTrint, readUnsignedTrint, readUTF, readXmlBean, readXmlSerializable, readXmlSerializable, realize, removeIntDecoration, removeIntDecoration, replace, reportIncompatibleSerializers, setObjectStreamFactory, toBinary, toBinary, toByteArray, toByteArray, toByteArray, toLiteBinary, toLong, undecorate, undecorate, validateBufferSize, writeBigDecimal, writeBigInteger, writeBooleanArray, writeByteArray, writeCollection, writeDate, writeDoubleArray, writeExternalizableLite, writeFloatArray, writeInt, writeInt, writeIntArray2d, writeLong, writeLong, writeMap, writeObject, writeSafeUTF, writeSafeUTF, writeSerializable, writeStringArray, writeTime, writeTimestamp, writeTrint, writeTrint, writeUTF, writeXmlBean, writeXmlSerializable

Methods inherited from class com.tangosol.util.BitHelper
countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString, toBytes, toBytes, toBytes, toBytes, toInt, toInt, toLong

Methods inherited from class com.tangosol.util.Base
azzert, azzert, azzert, azzertFailed, breakLines, breakLines, capitalize, checkNotEmpty, checkNotNull, checkRange, computeSafeWaitTime, decimalValue, dup, dup, ensureBigDecimal, ensureClassLoader, ensureRuntimeException, ensureRuntimeException, equals, equalsDeep, err, err, err, err, err, escape, formatDateTime, getCallerStackFrame, getCommonMonitor, getCommonMonitor, getCommonMonitor, getContextClassLoader, getContextClassLoader, getDeepMessage, getErr, getLastSafeTimeMillis, getLog, getMaxDecDigits, getMaxHexDigits, getOriginalException, getOut, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mod, mod, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, randomize, randomize, read, read, read, read, read, read, read, replace, setErr, setLog, setLogEcho, setOut, sleep, toBandwidthString, toBandwidthString, toCharEscape, toCrc, toCrc, toCrc, toCrc, toCrc, toDecString, toDelimitedString, toDelimitedString, toDelimitedString, toDelimitedString, toHex, toHex, toHexDump, toHexEscape, toHexEscape, toHexEscape, toHexEscape, toHexString, toMemorySizeString, toMemorySizeString, toQuotedCharEscape, toQuotedStringEscape, toSqlString, toString, toString, toStringEscape, toUnicodeEscape, trace, trace, trace, trace, trace, trace, trace, trace, trace, truncateString, truncateString, wait

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

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

- Field Detail
  - m_extractor
```
protected ValueExtractor<? super T,? extends E> m_extractor
```
    The underlying ValueExtractor.
  - m_aggregator
```
protected InvocableMap.EntryAggregator<? super K,? super V,R> m_aggregator
```
    The underlying EntryAggregator.
  - m_filter
```
protected Filter m_filter
```
    The Filter object representing the "having" clause of this "group by" aggregator.
  - m_fInit
```
protected transient boolean m_fInit
```
    Flag specifying whether this aggregator has been initialized.
  - m_fStreaming
```
protected transient boolean m_fStreaming
```
    Flag specifying whether streaming optimizations can be used.
  - m_fParallel
```
protected transient boolean m_fParallel
```
    Flag specifying whether parallel optimizations can be used.
  - m_mapResults
```
protected transient Map<E,Object> m_mapResults
```
    A map of partial results to aggregate.
- Constructor Detail
  - GroupAggregator
```
public GroupAggregator()
```
    Default constructor (necessary for the ExternalizableLite interface).
  - GroupAggregator
```
protected GroupAggregator(ValueExtractor<? super T,? extends E> extractor,
                          InvocableMap.EntryAggregator<? super K,? super V,R> aggregator,
                          Filter filter)
```
    Construct a GroupAggregator based on a specified ValueExtractor and underlying EntryAggregator.
    
    Parameters:
    
    extractor - a ValueExtractor object that is used to split InvocableMap entries into non-intersecting subsets; may not be null
    
    aggregator - an EntryAggregator object; may not be null
    
    filter - an optional Filter object used to filter out results of individual group aggregation results
- Method Detail
  - supply
```
public InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>> supply()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Create a new instance of this aggregator.
    
    Specified by:
    
    supply in interface InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>
  - 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,Map<E,Object>,Map<E,R>>
    
    Parameters:
    
    entry - the entry to accumulate into the aggregation result
    
    Returns:
    
    <c>true</c> to continue the aggregation, and <c>false</c> to signal to the caller that the result is ready and the aggregation can be short-circuited
  - combine
```
public boolean combine(Map<E,Object> partialResult)
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Merge another partial result into the result.
    
    Specified by:
    
    combine in interface InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>
    
    Parameters:
    
    partialResult - the partial result to merge
    
    Returns:
    
    <c>true</c> to continue the aggregation, and <c>false</c> to signal to the caller that the result is ready and the aggregation can be short-circuited
  - getPartialResult
```
public Map<E,Object> getPartialResult()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Return the partial result of the aggregation.
    
    Specified by:
    
    getPartialResult in interface InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>
    
    Returns:
    
    the partial result of the aggregation
  - finalizeResult
```
public Map<E,R> finalizeResult()
```
    Description copied from interface: InvocableMap.StreamingAggregator
    
    Return the final result of the aggregation.
    
    Specified by:
    
    finalizeResult in interface InvocableMap.StreamingAggregator<K,V,Map<E,Object>,Map<E,R>>
    
    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,Map<E,Object>,Map<E,R>>
    
    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
  - getExtractor
```
public ValueExtractor<?,? extends E> getExtractor()
```
    Obtain the underlying ValueExtractor.
    
    Returns:
    
    the underlying ValueExtractor
  - getAggregator
```
public InvocableMap.EntryAggregator<? super K,? super V,R> getAggregator()
```
    Obtain the underlying EntryAggregator.
    
    Returns:
    
    the underlying EntryAggregator
  - ensureInitialized
```
protected void ensureInitialized()
```
    Ensure that this aggregator is initialized.
  - streaming
```
protected InvocableMap.StreamingAggregator<? super K,? super V,Object,R> streaming(InvocableMap.EntryAggregator<? super K,? super V,R> aggregator)
```
    Convert the specified aggregator to StreamingAggregator.
    
    Parameters:
    
    aggregator - the aggregator to convert
    
    Returns:
    
    an instance of a StreamingAggregator
  - parallel
```
protected InvocableMap.ParallelAwareAggregator<? super K,? super V,Object,R> parallel(InvocableMap.EntryAggregator<? super K,? super V,R> aggregator)
```
    Convert the specified aggregator to ParallelAwareAggregator.
    
    Parameters:
    
    aggregator - the aggregator to convert
    
    Returns:
    
    an instance of a ParallelAwareAggregator
  - isDelegateStreaming
```
protected boolean isDelegateStreaming()
```
    Return <c>true</c> if the underlying aggregator is a StreamingAggregator.
    
    Returns:
    
    <c>true</c> if the underlying aggregator is a StreamingAggregator
  - isDelegateParallel
```
protected boolean isDelegateParallel()
```
    Return <c>true</c> if the underlying aggregator is a ParallelAwareAggregator.
    
    Returns:
    
    <c>true</c> if the underlying aggregator is a ParallelAwareAggregator
  - throwingMerger
```
protected static <T> BinaryOperator<T> throwingMerger()
```
  - readExternal
```
public void readExternal(DataInput in)
                  throws IOException
```
    Description copied from interface: ExternalizableLite
    
    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
```
    Description copied from interface: ExternalizableLite
    
    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
```
    Description copied from interface: PortableObject
    
    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
```
    Description copied from interface: PortableObject
    
    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
  - equals
```
public boolean equals(Object o)
```
    Compare the GroupAggregator with another object to determine equality.
    
    Overrides:
    
    equals in class Object
    
    Returns:
    
    true iff this GroupAggregator and the passed object are equivalent
  - hashCode
```
public int hashCode()
```
    Determine a hash value for the GroupAggregator object according to the general Object.hashCode() contract.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    an integer hash value for this GroupAggregator object
  - toString
```
public String toString()
```
    Return a human-readable description for this GroupAggregator.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a String description of the GroupAggregator
  - createInstance
```
public static <K,V,R> GroupAggregator<K,V,Object,Object,R> createInstance(String sMethod,
                                                                          InvocableMap.EntryAggregator<K,V,R> aggregator)
```
    Create an instance of GroupAggregator based on a specified method name(s) and an EntryAggregator.
    If the specified underlying aggregator is an instance of ParallelAwareAggregator, then a parallel-aware instance of the GroupAggregator will be created. Otherwise, the resulting GroupAggregator will not be parallel-aware and could be ill-suited for aggregations run against large partitioned caches.
    
    Parameters:
    
    sMethod - a method name or a comma-delimited sequence of names that results in a ReflectionExtractor or a MultiExtractor that will be used to split InvocableMap entries into distinct groups
    
    aggregator - an underlying EntryAggregator
  - createInstance
```
public static <K,V,R> GroupAggregator<K,V,Object,Object,R> createInstance(String sMethod,
                                                                          InvocableMap.EntryAggregator<K,V,R> aggregator,
                                                                          Filter filter)
```
    Create an instance of GroupAggregator based on a specified method name(s), an EntryAggregator and a result evaluation filter.
    If the specified underlying aggregator is an instance of ParallelAwareAggregator, then a parallel-aware instance of the GroupAggregator will be created. Otherwise, the resulting GroupAggregator will not be parallel-aware and could be ill-suited for aggregations run against large partitioned caches.
    
    Parameters:
    
    sMethod - a method name or a comma-delimited sequence of names that results in a ReflectionExtractor or a MultiExtractor that will be used to split InvocableMap entries into distinct groups
    
    aggregator - an underlying EntryAggregator
    
    filter - an optional Filter object that will be used to evaluate results of each individual group aggregation
  - createInstance
```
public static <K,V,T,E,R> GroupAggregator<K,V,T,E,R> createInstance(ValueExtractor<? super T,? extends E> extractor,
                                                                    InvocableMap.EntryAggregator<K,V,R> aggregator)
```
    Create an instance of GroupAggregator based on a specified extractor and an EntryAggregator.
    If the specified aggregator is an instance of ParallelAwareAggregator, then a parallel-aware instance of the GroupAggregator will be created. Otherwise, the resulting GroupAggregator will not be parallel-aware and could be ill-suited for aggregations run against large partitioned caches.
    
    Parameters:
    
    extractor - a ValueExtractor that will be used to split a set of InvocableMap entries into distinct groups
    
    aggregator - an underlying EntryAggregator
  - createInstance
```
public static <K,V,T,E,R> GroupAggregator<K,V,T,E,R> createInstance(ValueExtractor<? super T,? extends E> extractor,
                                                                    InvocableMap.EntryAggregator<? super K,? super V,R> aggregator,
                                                                    Filter filter)
```
    Create an instance of GroupAggregator based on a specified extractor and an EntryAggregator and a result evaluation filter.
    If the specified aggregator is an instance of ParallelAwareAggregator, then a parallel-aware instance of the GroupAggregator will be created. Otherwise, the resulting GroupAggregator will not be parallel-aware and could be ill-suited for aggregations run against large partitioned caches.
    
    Parameters:
    
    extractor - a ValueExtractor that will be used to split a set of InvocableMap entries into distinct groups
    
    aggregator - an underlying EntryAggregator
    
    filter - an optional Filter object used to filter out results of individual group aggregation results

Class GroupAggregator<K,V,T,E,R>

Nested Class Summary

Nested classes/interfaces inherited from class com.tangosol.util.ExternalizableHelper

Nested classes/interfaces inherited from class com.tangosol.util.Base

Field Summary

Fields inherited from class com.tangosol.util.ExternalizableHelper

Fields inherited from class com.tangosol.util.Base

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

Constructor Summary

Method Summary

Methods inherited from class com.tangosol.util.ExternalizableHelper

Methods inherited from class com.tangosol.util.BitHelper

Methods inherited from class com.tangosol.util.Base

Methods inherited from class java.lang.Object

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

Field Detail

m_extractor

m_aggregator

m_filter

m_fInit

m_fStreaming

m_fParallel

m_mapResults

Constructor Detail

GroupAggregator

GroupAggregator

Method Detail

supply

accumulate

combine

getPartialResult

finalizeResult

characteristics

getExtractor

getAggregator

ensureInitialized

streaming

parallel

isDelegateStreaming

isDelegateParallel

throwingMerger

readExternal

writeExternal

readExternal

writeExternal

equals

hashCode

toString

createInstance

createInstance

createInstance

createInstance