org.h2.value

Class CompareMode

java.lang.Object

org.h2.value.CompareMode

All Implemented Interfaces:

java.util.Comparator<Value>

Direct Known Subclasses:

CompareModeDefault, CompareModeIcu4J

public class CompareMode
extends java.lang.Object
implements java.util.Comparator<Value>

Instances of this class can compare strings. Case sensitive and case insensitive comparison is supported, and comparison using a collator.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CHARSET This constant means the charset specified should be used.
static java.lang.String	DEFAULT This constant means the default collator should be used, even if ICU4J is in the classpath.
static java.lang.String	ICU4J This constant means ICU4J should be used (this will fail if it is not in the classpath).
static java.lang.String	OFF This constant means there is no collator set, and the default string comparison is to be used.
static java.lang.String	SIGNED This constant means that the BINARY or UUID columns are sorted as if the bytes were signed.
static java.lang.String	UNSIGNED This constant means that the BINARY or UUID columns are sorted as if the bytes were unsigned.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CompareMode(java.lang.String name, int strength, boolean binaryUnsigned, boolean uuidUnsigned)

Method Summary

Methods

Modifier and Type	Method and Description
int	compare(Value o1, Value o2)
int	compareString(java.lang.String a, java.lang.String b, boolean ignoreCase) Compare two strings.
boolean	equals(java.lang.Object obj)
boolean	equalsChars(java.lang.String a, int ai, java.lang.String b, int bi, boolean ignoreCase) Compare two characters in a string.
static java.text.Collator	getCollator(java.lang.String name) Get the collator object for the given language name or language / country combination.
static CompareMode	getInstance(java.lang.String name, int strength) Create a new compare mode with the given collator and strength.
static CompareMode	getInstance(java.lang.String name, int strength, boolean binaryUnsigned, boolean uuidUnsigned) Create a new compare mode with the given collator and strength.
java.lang.String	getName()
static java.lang.String	getName(java.util.Locale l) Get the collation name.
int	getStrength()
int	hashCode()
boolean	isBinaryUnsigned()
boolean	isUuidUnsigned()

Methods inherited from class java.lang.Object

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

Field Detail

OFF

public static final java.lang.String OFF

This constant means there is no collator set, and the default string comparison is to be used.

See Also:

Constant Field Values

DEFAULT

public static final java.lang.String DEFAULT

This constant means the default collator should be used, even if ICU4J is in the classpath.

See Also:

Constant Field Values

ICU4J

public static final java.lang.String ICU4J

This constant means ICU4J should be used (this will fail if it is not in the classpath).

See Also:

Constant Field Values

CHARSET

public static final java.lang.String CHARSET

This constant means the charset specified should be used. This will fail if the specified charset does not exist.

See Also:

Constant Field Values

SIGNED

public static final java.lang.String SIGNED

This constant means that the BINARY or UUID columns are sorted as if the bytes were signed.

See Also:

Constant Field Values

UNSIGNED

public static final java.lang.String UNSIGNED

This constant means that the BINARY or UUID columns are sorted as if the bytes were unsigned.

See Also:

Constant Field Values

Constructor Detail

CompareMode

protected CompareMode(java.lang.String name,
           int strength,
           boolean binaryUnsigned,
           boolean uuidUnsigned)

Method Detail

getInstance

public static CompareMode getInstance(java.lang.String name,
                      int strength)

Create a new compare mode with the given collator and strength. If required, a new CompareMode is created, or if possible the last one is returned. A cache is used to speed up comparison when using a collator; CollationKey objects are cached.

Parameters:

name - the collation name or null

strength - the collation strength

Returns:

the compare mode

getInstance

public static CompareMode getInstance(java.lang.String name,
                      int strength,
                      boolean binaryUnsigned,
                      boolean uuidUnsigned)

Create a new compare mode with the given collator and strength. If required, a new CompareMode is created, or if possible the last one is returned. A cache is used to speed up comparison when using a collator; CollationKey objects are cached.

Parameters:

name - the collation name or null

strength - the collation strength

binaryUnsigned - whether to compare binaries as unsigned

uuidUnsigned - whether to compare UUIDs as unsigned

Returns:

the compare mode

equalsChars

public boolean equalsChars(java.lang.String a,
                  int ai,
                  java.lang.String b,
                  int bi,
                  boolean ignoreCase)

Compare two characters in a string.

Parameters:

a - the first string

ai - the character index in the first string

b - the second string

bi - the character index in the second string

ignoreCase - true if a case-insensitive comparison should be made

Returns:

true if the characters are equals

compareString

public int compareString(java.lang.String a,
                java.lang.String b,
                boolean ignoreCase)

Compare two strings.

Parameters:

a - the first string

b - the second string

ignoreCase - true if a case-insensitive comparison should be made

Returns:

-1 if the first string is 'smaller', 1 if the second string is smaller, and 0 if they are equal

getName

public static java.lang.String getName(java.util.Locale l)

Get the collation name.

Parameters:

l - the locale

Returns:

the name of the collation

getCollator

public static java.text.Collator getCollator(java.lang.String name)

Get the collator object for the given language name or language / country combination.

Parameters:

name - the language name

Returns:

the collator

getName

public java.lang.String getName()

getStrength

public int getStrength()

isBinaryUnsigned

public boolean isBinaryUnsigned()

isUuidUnsigned

public boolean isUuidUnsigned()

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Comparator<Value>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

compare

public int compare(Value o1,
          Value o2)

Specified by:

compare in interface java.util.Comparator<Value>