com.tangosol.util.comparator.SafeComparator<T>

All Implemented Interfaces:: ExternalizableLite, PortableObject, EntryAwareComparator<T>, QueryMapComparator<T>, Remote.Comparator<T>, Serializable, Comparator<T>

Direct Known Subclasses:: EntryComparator, InverseComparator

public class SafeComparator<T> extends Base implements Remote.Comparator<T>, QueryMapComparator<T>, EntryAwareComparator<T>, Serializable, ExternalizableLite, PortableObject

Null-safe delegating comparator. Null values are evaluated as "less then" any non-null value. If the wrapped comparator is not specified then all non-null values must implement the Comparable interface.

Use SafeComparator.INSTANCE to obtain an instance of non-delegating SafeComparator.

Author:

gg 2002.12.10

See Also:

Nested Class Summary

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

Fields

Modifier and Type

Field

Description

static final SafeComparator

INSTANCE

The trivial SafeComparator.

protected Comparator<? super T>

m_comparator

The wrapped Comparator.

protected boolean

m_fNullFirst

Flag specifying if nulls should be sorted as less (first) or greater (last) than all non-null elements.

Fields inherited from class com.tangosol.util.Base
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
Constructor Summary

Constructors

Constructor

Description

SafeComparator()

Default constructor (for ExternalizableLite and PortableObject).

SafeComparator(Comparator<? super T> comparator)

Construct a SafeComparator delegating to the specified (wrapped) comparator.

SafeComparator(Comparator<? super T> comparator, boolean fNullFirst)

Construct a SafeComparator delegating to the specified (wrapped) comparator.
Method Summary

Modifier and Type

Method

Description

int

compare(T o1, T o2)

Compares its two arguments for order.

int

compareEntries(QueryMap.Entry entry1, QueryMap.Entry entry2)

Compare two entries using the underlying comparator.

static <T> int

compareSafe(Comparator comparator, Object o1, Object o2)

Compares its two arguments for order.

static int

compareSafe(Comparator comparator, Object o1, Object o2, boolean fNullFirst)

Compares its two arguments for order.

static <V> Comparator<? super V>

ensureSafe(Comparator<? super V> comparator)

Ensure that the specified comparator is safe, by wrapping it if it isn't.

boolean

equals(Object o)

Determine if two comparators are equal.

Comparator<? super T>

getComparator()

Obtain the wrapped Comparator.

int

hashCode()

Return the hash code for this comparator.

static <T> SafeComparator<T>

INSTANCE()

Return the trivial SafeComparator.

boolean

isKeyComparator()

Specifies whether this comparator expects to compare keys or values.

static boolean

isKeyComparator(Comparator comparator)

Check whether the specified comparator expects to compare keys or values.

boolean

isNullFirst()

Obtain the m_fNullFirst flag.

void

readExternal(PofReader in)

Restore the contents of a user type instance by reading its state using the specified PofReader object.

void

readExternal(DataInput in)

Restore the contents of this object by loading the object's state from the passed DataInput object.

String

toString()

Return a human-readable description for this Comparator.

void

writeExternal(PofWriter out)

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

void

writeExternal(DataOutput out)

Save the contents of this object by storing the object's state into the passed DataOutput object.

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, 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 java.util.Comparator
thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Methods inherited from interface com.tangosol.util.function.Remote.Comparator
reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Details
- INSTANCE
  
  public static final SafeComparator INSTANCE
  
  The trivial SafeComparator.
- m_comparator
  
  protected Comparator<? super T> m_comparator
  
  The wrapped Comparator. Could be null.
- m_fNullFirst
  
  protected boolean m_fNullFirst
  
  Flag specifying if nulls should be sorted as less (first) or greater (last) than all non-null elements. Default is "less than" (first).
Constructor Details
- SafeComparator
  
  public SafeComparator()
  
  Default constructor (for ExternalizableLite and PortableObject).
- SafeComparator
  
  public SafeComparator(Comparator<? super T> comparator)
  
  Construct a SafeComparator delegating to the specified (wrapped) comparator.
  
  Parameters:
  
  comparator - Comparator object to delegate comparison of non-null values (optional)
- SafeComparator
  
  public SafeComparator(Comparator<? super T> comparator, boolean fNullFirst)
  
  Construct a SafeComparator delegating to the specified (wrapped) comparator.
  
  Parameters:
  
  comparator - Comparator object to delegate comparison of non-null values (optional)
  
  fNullFirst - flag specifying if null values should be treated as "less than" (true) or "greater than" (false) any non-null value
Method Details
- ensureSafe
  
  public static <V> Comparator<? super V> ensureSafe(Comparator<? super V> comparator)
  
  Ensure that the specified comparator is safe, by wrapping it if it isn't.
  
  Type Parameters:
  
  V - the type of objects to compare
  
  Parameters:
  
  comparator - the comparator to wrap, if necessary
  
  Returns:
  
  a SafeComparator for the specified comparator
- compare
  
  public int compare(T o1, T o2)
  
  Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. Null values are evaluated as "less then" any non-null value. If the wrapped comparator is not specified, all non-null values must implement the Comparable interface.
  
  Specified by:
  
  compare in interface Comparator<T>
  
  Parameters:
  
  o1 - the first object to be compared
  
  o2 - the second object to be compared
  
  Returns:
  
  a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second
  
  Throws:
  
  ClassCastException - if the arguments' types prevent them from being compared by this Comparator.
- compareEntries
  
  public int compareEntries(QueryMap.Entry entry1, QueryMap.Entry entry2)
  
  Compare two entries using the underlying comparator. If the wrapped comparator does not implement the QueryMapComparator interface, revert to the entry values comparison.
  
  Specified by:
  
  compareEntries in interface QueryMapComparator<T>
  
  Parameters:
  
  entry1 - the first entry to compare values from; read-only
  
  entry2 - the second entry to compare values from; read-only
  
  Returns:
  
  a negative integer, zero, or a positive integer as the first entry denotes a value that is is less than, equal to, or greater than the value denoted by the second entry
- isKeyComparator
  
  public boolean isKeyComparator()
  
  Specifies whether this comparator expects to compare keys or values.
  
  Specified by:
  
  isKeyComparator in interface EntryAwareComparator<T>
  
  Returns:
  
  true if Entry keys are expected; false otherwise
- isKeyComparator
  
  public static boolean isKeyComparator(Comparator comparator)
  
  Check whether the specified comparator expects to compare keys or values.
  
  Parameters:
  
  comparator - a Comparator to check
  
  Returns:
  
  true if the comparator expects keys; false otherwise
- getComparator
  
  public Comparator<? super T> getComparator()
  
  Obtain the wrapped Comparator.
  
  Returns:
  
  the wrapped Comparator
- isNullFirst
  
  public boolean isNullFirst()
  
  Obtain the m_fNullFirst flag.
  
  Returns:
  
  the m_fNullFirst flag
- compareSafe
  
  public static <T> int compareSafe(Comparator comparator, Object o1, Object o2)
  
  Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. Null values are evaluated as "less then" any non-null value. Non-null values must implement the Comparable interface.
  
  Parameters:
  
  comparator - a comparator to use for the comparison (optional)
  
  o1 - the first object to be compared
  
  o2 - the second object to be compared
  
  Returns:
  
  a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second
  
  Throws:
  
  ClassCastException - if the arguments are not Comparable
- compareSafe
  
  public static int compareSafe(Comparator comparator, Object o1, Object o2, boolean fNullFirst)
  
  Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. Null values are evaluated based on the value of a fNullFirst flag as either "less than" or "greater than" any non-null value. Non-null values must implement the Comparable interface.
  
  Parameters:
  
  comparator - a comparator to use for the comparison (optional)
  
  o1 - the first object to be compared
  
  o2 - the second object to be compared
  
  fNullFirst - flag specifying if null values should be treated as "less than" (true) or "greater than" (false) any non-null value
  
  Returns:
  
  a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second
  
  Throws:
  
  ClassCastException - if the arguments are not Comparable
- toString
  
  public String toString()
  
  Return a human-readable description for this Comparator.
  
  Overrides:
  
  toString in class Object
  
  Returns:
  
  a String description of the Comparator
- equals
  
  public boolean equals(Object o)
  
  Determine if two comparators are equal.
  
  Specified by:
  
  equals in interface Comparator<T>
  
  Overrides:
  
  equals in class Object
  
  Parameters:
  
  o - the other comparator
  
  Returns:
  
  true if the passed object is equal to this
- hashCode
  
  public int hashCode()
  
  Return the hash code for this comparator.
  
  Overrides:
  
  hashCode in class Object
  
  Returns:
  
  the hash code value for this comparator
- 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
- 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
- INSTANCE
  
  public static <T> SafeComparator<T> INSTANCE()
  
  Return the trivial SafeComparator.

Class SafeComparator<T>

Nested Class Summary

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

Field Summary

Fields inherited from class com.tangosol.util.Base

Constructor Summary

Method Summary

Methods inherited from class com.tangosol.util.Base

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Comparator

Methods inherited from interface com.tangosol.util.function.Remote.Comparator

Field Details

INSTANCE

m_comparator

m_fNullFirst

Constructor Details

SafeComparator

SafeComparator

SafeComparator

Method Details

ensureSafe

compare

compareEntries

isKeyComparator

isKeyComparator

getComparator

isNullFirst

compareSafe

compareSafe

toString

equals

hashCode

readExternal

writeExternal

readExternal

writeExternal

INSTANCE