Package com.tangosol.util.aggregator

Class DistinctValues<K,V,T,E>

java.lang.Object

com.tangosol.util.Base

com.tangosol.util.BitHelper

com.tangosol.util.ExternalizableHelper

com.tangosol.util.aggregator.AbstractAggregator<K,V,T,E,Collection<E>>

com.tangosol.util.aggregator.DistinctValues<K,V,T,E>

Type Parameters:

T - the type of the value to extract from

E - the type of the extracted value

All Implemented Interfaces:

ExternalizableLite, PortableObject, InvocableMap.EntryAggregator<K,V,Collection<E>>, InvocableMap.StreamingAggregator<K,V,Object,Collection<E>>, Serializable, Cloneable

public class DistinctValues<K,V,T,E>
extends AbstractAggregator<K,V,T,E,Collection<E>>

Return the set of unique values extracted from a set of entries in a Map. If the set of entries is empty, an empty set is returned.

This aggregator could be used in combination with MultiExtractor allowing to collect all unique combinations (tuples) of a given set of attributes.

The DistinctValues aggregator covers a simple case of a more generic aggregation pattern implemented by the GroupAggregator, which in addition to collecting all distinct values or tuples, runs an aggregation against each distinct entry set (group).

Author:

jh 2005.12.20

See Also:

• Serialized Form

Nested Class Summary

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

Field Summary

Fields

Modifier and Type	Field	Description
protected Set<E>	m_set	The resulting set of distinct values.

Fields inherited from class com.tangosol.util.aggregator.AbstractAggregator

m_fParallel

Fields inherited from class com.tangosol.util.ExternalizableHelper

BINARY_SIZE, CHUNK_SIZE, CHUNK_THRESHOLD, CONVERTER_FROM_BINARY, CONVERTER_STRIP_INTDECO, CONVERTER_TO_BINARY, DECO_APP_1, DECO_APP_2, DECO_APP_3, DECO_BACKUP, 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_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, LAMBDA_SERIALIZATION, MAX_DECO_HEADER_BYTES, PACKED_INT_SIZE, PACKED_LONG_SIZE, 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

DEFAULT_LOAD_FACTOR, LOG_ALWAYS, LOG_CONFIG, 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

ALLOW_INCONSISTENCIES, BY_MEMBER, BY_PARTITION, PARALLEL, PRESENT_ONLY, RETAINS_ENTRIES, SERIAL

Constructor Summary

Constructors

Constructor	Description
DistinctValues()	Default constructor (necessary for the ExternalizableLite interface).
DistinctValues(ValueExtractor<? super T,? extends E> extractor)	Construct a DistinctValues aggregator.
DistinctValues(String sMethod)	Construct an DistinctValues aggregator.

Method Summary

Modifier and Type	Method	Description
boolean	accumulate(Streamer<? extends InvocableMap.Entry<? extends K,? extends V>> streamer)	Accumulate multiple entries into the result.
int	characteristics()	A bit mask representing the set of characteristics of this aggregator.
protected Set<E>	ensureSet()	Return a set that can be used to store distinct values, creating it if one has not already been created.
protected Set<E>	finalizeResult(boolean fFinal)	Obtain the result of the aggregation.
protected void	init(boolean fFinal)	Initialize the aggregation result.
protected void	process(Object o, boolean fFinal)	Incorporate one aggregatable value into the result.
InvocableMap.StreamingAggregator<K,V,Object,Collection<E>>	supply()	Create a new instance of this aggregator.

Methods inherited from class com.tangosol.util.aggregator.AbstractAggregator

accumulate, combine, ensureInitialized, equals, finalizeResult, getPartialResult, getValueExtractor, hashCode, processEntry, readExternal, readExternal, toString, writeExternal, writeExternal

Methods inherited from class com.tangosol.util.ExternalizableHelper

asBinary, calculatePackedLength, calculatePackedLength, checkObjectInputFilter, checkObjectInputFilter, checkObjectInputFilter, convertUTF, decodeExpiry, decorate, decorate, decorate, decorate, decorate, decorateBinary, encodeExpiry, ensureSerializer, extractIntDecoration, fromBinary, fromBinary, fromBinary, fromBinary, fromBinary, fromBinary, fromByteArray, fromByteArray, getClass, getConfigSerialFilter, getConfigSerialFilterFactory, getDecoration, getDecoration, getDecorations, getDeltaCompressor, getInputStream, getNewObjectInput, getObjectInput, getObjectInputFilter, getObjectOutput, getObjectStreamFactory, getOutputStream, getShieldedOutputStream, getStreamFormat, getUndecorated, getUndecorated, isDecorated, isDecorated, isIntDecorated, isIntDecorated, isPatchCompatible, isPatchCompatible, isResolving, isSerializable, isSerializerCompatible, isVersionCompatible, isVersionCompatible, isVersionCompatible, isVersionCompatible, isVersionCompatible, isVersionCompatible, loadClass, loadResource, main, makeTrint, readBigDecimal, readBigInteger, readBooleanArray, readBooleanArray, readByteArray, readCharArray, readCharArray, readCollection, readDate, readDoubleArray, readDoubleArray, readExternalizableLite, readExternalizableLite, readFloatArray, readFloatArray, readInt, readInt, readIntArray, readIntArray, readIntArray2d, readLargeBooleanArray, readLargeByteArray, readLargeCharArray, readLargeDoubleArray, readLargeFloatArray, readLargeIntArray, readLargeLongArray, readLargeObjectArray, readLargeStringArray, readLong, readLong, readLongArray, readLongArray, readMap, readMap, readObject, readObject, readObjectArray, readObjectArray, readSafeUTF, readSafeUTF, readSerializable, readSerializable, readStringArray, readStringArray, readTime, readTimestamp, readTrint, readUnsignedTrint, readUTF, readXmlBean, readXmlSerializable, readXmlSerializable, realize, removeIntDecoration, removeIntDecoration, replace, reportIncompatibleSerializers, setObjectStreamFactory, toBinary, toBinary, toBinary, toByteArray, toByteArray, toByteArray, toLiteBinary, toLong, undecorate, undecorate, validateBufferSize, validateLoadArray, validateLoadClass, 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, getProcessRandom, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mergeArray, mergeBooleanArray, mergeByteArray, mergeCharArray, mergeDoubleArray, mergeFloatArray, mergeIntArray, mergeLongArray, mod, mod, newHashMap, newHashMap, newHashSet, newHashSet, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, 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

aggregate, isAllowInconsistencies, isByMember, isByPartition, isParallel, isPresentOnly, isRetainsEntries, isSerial

Field Details

m_set

protected transient Set<E> m_set

The resulting set of distinct values.

Constructor Details

DistinctValues

public DistinctValues()

Default constructor (necessary for the ExternalizableLite interface).

DistinctValues

public DistinctValues(ValueExtractor<? super T,? extends E> extractor)

Construct a DistinctValues aggregator.

Parameters:

extractor - the extractor that provides a value in the form of any Java object

DistinctValues

public DistinctValues(String sMethod)

Construct an DistinctValues aggregator.

Parameters:

sMethod - the name of the method that returns a value in the form of any Java object

Method Details

supply

public InvocableMap.StreamingAggregator<K,V,Object,Collection<E>> supply()

Description copied from interface: InvocableMap.StreamingAggregator

Create a new instance of this aggregator.

Specified by:

supply in interface InvocableMap.StreamingAggregator<K,V,T,E>

Overrides:

supply in class AbstractAggregator<K,V,T,E,Collection<E>>

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,T,E>

Overrides:

accumulate in class AbstractAggregator<K,V,T,E,Collection<E>>

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

characteristics

public int characteristics()

Description copied from interface: InvocableMap.StreamingAggregator

A bit mask representing the set of characteristics of this aggregator.

By 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).

Returns:

a bit mask representing the set of characteristics of this aggregator

See Also:

• InvocableMap.StreamingAggregator.ALLOW_INCONSISTENCIES
• InvocableMap.StreamingAggregator.BY_MEMBER
• InvocableMap.StreamingAggregator.BY_PARTITION
• InvocableMap.StreamingAggregator.PARALLEL
• InvocableMap.StreamingAggregator.PRESENT_ONLY
• InvocableMap.StreamingAggregator.RETAINS_ENTRIES
• InvocableMap.StreamingAggregator.SERIAL

init

protected void init(boolean fFinal)

Initialize the aggregation result.

Specified by:

init in class AbstractAggregator<K,V,T,E,Collection<E>>

Parameters:

fFinal - true is passed if the aggregation process that is being initialized must produce a final aggregation result; this will only be false if a parallel approach is being used and the initial (partial) aggregation process is being initialized

process

protected void process(Object o,
 boolean fFinal)

Incorporate one aggregatable value into the result.

If the fFinal parameter is true, the given object is a partial result (returned by an individual parallel aggregator) that should be incorporated into the final result; otherwise, the object is a value extracted from an InvocableMap.Entry.

Specified by:

process in class AbstractAggregator<K,V,T,E,Collection<E>>

Parameters:

o - the value to incorporate into the aggregated result

fFinal - true to indicate that the given object is a partial result returned by a parallel aggregator

finalizeResult

protected Set<E> finalizeResult(boolean fFinal)

Obtain the result of the aggregation.

If the fFinal parameter is true, the returned object must be the final result of the aggregation; otherwise, the returned object will be treated as a partial result that should be incorporated into the final result.

Specified by:

finalizeResult in class AbstractAggregator<K,V,T,E,Collection<E>>

Parameters:

fFinal - true to indicate that the final result of the aggregation process should be returned; this will only be false if a parallel approach is being used

Returns:

the result of the aggregation process

ensureSet

protected Set<E> ensureSet()

Return a set that can be used to store distinct values, creating it if one has not already been created.

Returns:

a set that can be used to store distinct values