org.apache.commons.lang

Class BooleanUtils


public class BooleanUtils
extends java.lang.Object

Operations on boolean primitives and Boolean objects.

This class tries to handle null input gracefully. An exception will not be thrown for a null input. Each method documents its behaviour in more detail.

Version:
$Id: BooleanUtils.java,v 1.14 2003/08/22 17:25:33 ggregory Exp $

Authors:
Stephen Colebourne
Matthew Hawthorne
Gary Gregory

Since:
2.0

Constructor Summary

BooleanUtils()
BooleanUtils instances should NOT be constructed in standard programming.

Method Summary

static Boolean
negate(Boolean bool)
Negates the specified boolean.
static boolean
toBoolean(Boolean bool)
Converts a Boolean to a boolean handling null by returning false.
static boolean
toBoolean(Integer value, Integer trueValue, Integer falseValue)
Converts an Integer to a boolean specifying the conversion values.
static boolean
toBoolean(String str)
Converts a String to a boolean.
static boolean
toBoolean(String str, String trueString, String falseString)
Converts a String to a Boolean throwing an exception if no match found.
static boolean
toBoolean(int value)
Converts an int to a boolean using the convention that zero is false.
static boolean
toBoolean(int value, int trueValue, int falseValue)
Converts an int to a boolean specifying the conversion values.
static boolean
toBooleanDefaultIfNull(Boolean bool, boolean valueIfNull)
Converts a Boolean to a boolean handling null.
static Boolean
toBooleanObject(Integer value)
Converts an Integer to a Boolean using the convention that zero is false.
static Boolean
toBooleanObject(Integer value, Integer trueValue, Integer falseValue, Integer nullValue)
Converts an Integer to a Boolean specifying the conversion values.
static Boolean
toBooleanObject(String str)
Converts a String to a Boolean.
static Boolean
toBooleanObject(String str, String trueString, String falseString, String nullString)
Converts a String to a Boolean throwing an exception if no match.
static Boolean
toBooleanObject(boolean bool)
Boolean factory that avoids creating new Boolean objecs all the time.
static Boolean
toBooleanObject(int value)
Converts an int to a Boolean using the convention that zero is false.
static Boolean
toBooleanObject(int value, int trueValue, int falseValue, int nullValue)
Converts an int to a Boolean specifying the conversion values.
static int
toInteger(Boolean bool, int trueValue, int falseValue, int nullValue)
Converts a Boolean to an int specifying the conversion values.
static int
toInteger(boolean bool)
Converts a boolean to an int using the convention that zero is false.
static int
toInteger(boolean bool, int trueValue, int falseValue)
Converts a boolean to an int specifying the conversion values.
static Integer
toIntegerObject(Boolean bool)
Converts a Boolean to a Integer using the convention that zero is false.
static Integer
toIntegerObject(Boolean bool, Integer trueValue, Integer falseValue, Integer nullValue)
Converts a Boolean to an Integer specifying the conversion values.
static Integer
toIntegerObject(boolean bool)
Converts a boolean to an Integer using the convention that zero is false.
static Integer
toIntegerObject(boolean bool, Integer trueValue, Integer falseValue)
Converts a boolean to an Integer specifying the conversion values.
static String
toString(Boolean bool, String trueString, String falseString, String nullString)
Converts a Boolean to a String returning one of the input Strings.
static String
toString(boolean bool, String trueString, String falseString)
Converts a boolean to a String returning one of the input Strings.
static String
toStringOnOff(Boolean bool)
Converts a Boolean to a String returning 'on', 'off', or null.
static String
toStringOnOff(boolean bool)
Converts a boolean to a String returning 'on' or 'off'.
static String
toStringTrueFalse(Boolean bool)
Converts a Boolean to a String returning 'true', 'false', or null.
static String
toStringTrueFalse(boolean bool)
Converts a boolean to a String returning 'true' or 'false'.
static String
toStringYesNo(Boolean bool)
Converts a Boolean to a String returning 'yes', 'no', or null.
static String
toStringYesNo(boolean bool)
Converts a boolean to a String returning 'yes' or 'no'.
static Boolean
xor(Boolean[] array)
Performs an xor on an array of Booleans.
static boolean
xor(boolean[] array)
Performs an xor on a set of booleans.

Constructor Details

BooleanUtils

public BooleanUtils()
BooleanUtils instances should NOT be constructed in standard programming. Instead, the class should be used as BooleanUtils.toBooleanObject(true);.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Details

negate

public static Boolean negate(Boolean bool)
Negates the specified boolean.

If null is passed in, null will be returned.

Parameters:
bool - the Boolean to negate, may be null

Returns:
the negated Boolean, or null if null input


toBoolean

public static boolean toBoolean(Boolean bool)
Converts a Boolean to a boolean handling null by returning false.

Parameters:
bool - the boolean to convert

Returns:
true or false, null returns false


toBoolean

public static boolean toBoolean(Integer value,
                                Integer trueValue,
                                Integer falseValue)
Converts an Integer to a boolean specifying the conversion values.

Parameters:
value - the Integer to convert
trueValue - the value to match for true, may be null
falseValue - the value to match for false, may be null

Returns:
true or false


toBoolean

public static boolean toBoolean(String str)
Converts a String to a boolean.

'true', 'on' or 'yes' (case insensitive) will return true. Otherwise, false is returned.

Parameters:
str - the String to check

Returns:
the boolean value of the string, false if no match


toBoolean

public static boolean toBoolean(String str,
                                String trueString,
                                String falseString)
Converts a String to a Boolean throwing an exception if no match found.

null is returned if there is no match.

Parameters:
str - the String to check
trueString - the String to match for true (case sensitive), may be null
falseString - the String to match for false (case sensitive), may be null

Returns:
the boolean value of the string


toBoolean

public static boolean toBoolean(int value)
Converts an int to a boolean using the convention that zero is false.

Parameters:
value - the int to convert

Returns:
true if non-zero, false if zero


toBoolean

public static boolean toBoolean(int value,
                                int trueValue,
                                int falseValue)
Converts an int to a boolean specifying the conversion values.

Parameters:
value - the Integer to convert
trueValue - the value to match for true
falseValue - the value to match for false

Returns:
true or false


toBooleanDefaultIfNull

public static boolean toBooleanDefaultIfNull(Boolean bool,
                                             boolean valueIfNull)
Converts a Boolean to a boolean handling null.

Parameters:
bool - the boolean to convert
valueIfNull - the boolean value to return if null

Returns:
true or false


toBooleanObject

public static Boolean toBooleanObject(Integer value)
Converts an Integer to a Boolean using the convention that zero is false.

null will be converted to null.

Parameters:
value - the Integer to convert

Returns:
Boolean.TRUE if non-zero, Boolean.FALSE if zero, null if null input


toBooleanObject

public static Boolean toBooleanObject(Integer value,
                                      Integer trueValue,
                                      Integer falseValue,
                                      Integer nullValue)
Converts an Integer to a Boolean specifying the conversion values.

Parameters:
value - the Integer to convert
trueValue - the value to match for true, may be null
falseValue - the value to match for false, may be null
nullValue - the value to to match for null, may be null

Returns:
Boolean.TRUE, Boolean.FALSE, or null


toBooleanObject

public static Boolean toBooleanObject(String str)
Converts a String to a Boolean.

'true', 'on' or 'yes' (case insensitive) will return true. 'false', 'off' or 'no' (case insensitive) will return false. Otherwise, null is returned.

Parameters:
str - the String to check

Returns:
the Boolean value of the string, null if no match or null input


toBooleanObject

public static Boolean toBooleanObject(String str,
                                      String trueString,
                                      String falseString,
                                      String nullString)
Converts a String to a Boolean throwing an exception if no match.

Parameters:
str - the String to check
trueString - the String to match for true (case sensitive), may be null
falseString - the String to match for false (case sensitive), may be null
nullString - the String to match for null (case sensitive), may be null

Returns:
the Boolean value of the string, null if no match or null input


toBooleanObject

public static Boolean toBooleanObject(boolean bool)
Boolean factory that avoids creating new Boolean objecs all the time.

This method was added to JDK1.4 but is available here for earlier JDKs.

Parameters:
bool - the boolean to convert

Returns:
Boolean.TRUE or Boolean.FALSE as appropriate


toBooleanObject

public static Boolean toBooleanObject(int value)
Converts an int to a Boolean using the convention that zero is false.

Parameters:
value - the int to convert

Returns:
Boolean.TRUE if non-zero, Boolean.FALSE if zero, null if null


toBooleanObject

public static Boolean toBooleanObject(int value,
                                      int trueValue,
                                      int falseValue,
                                      int nullValue)
Converts an int to a Boolean specifying the conversion values.

Parameters:
value - the Integer to convert
trueValue - the value to match for true
falseValue - the value to match for false
nullValue - the value to to match for null

Returns:
Boolean.TRUE, Boolean.FALSE, or null


toInteger

public static int toInteger(Boolean bool,
                            int trueValue,
                            int falseValue,
                            int nullValue)
Converts a Boolean to an int specifying the conversion values.

Parameters:
bool - the Boolean to convert
trueValue - the value to return if true
falseValue - the value to return if false
nullValue - the value to return if null

Returns:
the appropriate value


toInteger

public static int toInteger(boolean bool)
Converts a boolean to an int using the convention that zero is false.

Parameters:
bool - the boolean to convert

Returns:
one if true, zero if false


toInteger

public static int toInteger(boolean bool,
                            int trueValue,
                            int falseValue)
Converts a boolean to an int specifying the conversion values.

Parameters:
bool - the to convert
trueValue - the value to return if true
falseValue - the value to return if false

Returns:
the appropriate value


toIntegerObject

public static Integer toIntegerObject(Boolean bool)
Converts a Boolean to a Integer using the convention that zero is false.

null will be converted to null.

Parameters:
bool - the Boolean to convert

Returns:
one if Boolean.TRUE, zero if Boolean.FALSE, null if null


toIntegerObject

public static Integer toIntegerObject(Boolean bool,
                                      Integer trueValue,
                                      Integer falseValue,
                                      Integer nullValue)
Converts a Boolean to an Integer specifying the conversion values.

Parameters:
bool - the Boolean to convert
trueValue - the value to return if true, may be null
falseValue - the value to return if false, may be null
nullValue - the value to return if null, may be null

Returns:
the appropriate value


toIntegerObject

public static Integer toIntegerObject(boolean bool)
Converts a boolean to an Integer using the convention that zero is false.

Parameters:
bool - the boolean to convert

Returns:
one if true, zero if false


toIntegerObject

public static Integer toIntegerObject(boolean bool,
                                      Integer trueValue,
                                      Integer falseValue)
Converts a boolean to an Integer specifying the conversion values.

Parameters:
bool - the to convert
trueValue - the value to return if true, may be null
falseValue - the value to return if false, may be null

Returns:
the appropriate value


toString

public static String toString(Boolean bool,
                              String trueString,
                              String falseString,
                              String nullString)
Converts a Boolean to a String returning one of the input Strings.

Parameters:
bool - the Boolean to check
trueString - the String to return if true, may be null
falseString - the String to return if false, may be null
nullString - the String to return if null, may be null

Returns:
one of the three input Strings


toString

public static String toString(boolean bool,
                              String trueString,
                              String falseString)
Converts a boolean to a String returning one of the input Strings.

Parameters:
bool - the Boolean to check
trueString - the String to return if true, may be null
falseString - the String to return if false, may be null

Returns:
one of the two input Strings


toStringOnOff

public static String toStringOnOff(Boolean bool)
Converts a Boolean to a String returning 'on', 'off', or null.

Parameters:
bool - the Boolean to check

Returns:
'on', 'off', or null


toStringOnOff

public static String toStringOnOff(boolean bool)
Converts a boolean to a String returning 'on' or 'off'.

Parameters:
bool - the Boolean to check

Returns:
'on', 'off', or null


toStringTrueFalse

public static String toStringTrueFalse(Boolean bool)
Converts a Boolean to a String returning 'true', 'false', or null.

Parameters:
bool - the Boolean to check

Returns:
'true', 'false', or null


toStringTrueFalse

public static String toStringTrueFalse(boolean bool)
Converts a boolean to a String returning 'true' or 'false'.

Parameters:
bool - the Boolean to check

Returns:
'true', 'false', or null


toStringYesNo

public static String toStringYesNo(Boolean bool)
Converts a Boolean to a String returning 'yes', 'no', or null.

Parameters:
bool - the Boolean to check

Returns:
'yes', 'no', or null


toStringYesNo

public static String toStringYesNo(boolean bool)
Converts a boolean to a String returning 'yes' or 'no'.

Parameters:
bool - the Boolean to check

Returns:
'yes', 'no', or null


xor

public static Boolean xor(Boolean[] array)
Performs an xor on an array of Booleans.

Parameters:
array - an array of Booleans

Returns:
true if the xor is successful.


xor

public static boolean xor(boolean[] array)
Performs an xor on a set of booleans.

Parameters:
array - an array of booleans

Returns:
true if the xor is successful.


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