org.apache.commons.lang
Class BooleanUtils

java.lang.Object
  org.apache.commons.lang.BooleanUtils

public class BooleanUtils

extends 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.

Since:

2.0

Version:

$Id: BooleanUtils.java 161243 2005-04-14 04:30:28Z ggregory $

Author:

Stephen Colebourne, Matthew Hawthorne, Gary Gregory

Constructor Summary

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

Method Summary

static boolean	isFalse(Boolean bool) Is a Boolean value false, handling null.
static boolean	isTrue(Boolean bool) Is a Boolean value true, handling null.
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(int value) Converts an int to a boolean using the convention that zero is false.
static boolean	toBoolean(Integer value, Integer trueValue, Integer falseValue) Converts an Integer to a boolean specifying the conversion values.
static boolean	toBoolean(int value, int trueValue, int falseValue) Converts an int to a boolean specifying the conversion values.
static boolean	toBoolean(String str) Converts a String to a boolean (optimised for performance).
static boolean	toBoolean(String str, String trueString, String falseString) Converts a String to a Boolean throwing an exception if no match found.
static boolean	toBooleanDefaultIfNull(Boolean bool, boolean valueIfNull) Converts a Boolean to a boolean handling null.
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(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(int value, int trueValue, int falseValue, int nullValue) Converts an int 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 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 int	toInteger(Boolean bool, int trueValue, int falseValue, int nullValue) Converts a Boolean to an int 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) Converts a Boolean to a 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 Integer	toIntegerObject(Boolean bool, Integer trueValue, Integer falseValue, Integer nullValue) Converts a Boolean to an Integer specifying the conversion values.
static String	toString(boolean bool, String trueString, String falseString) Converts a boolean to a String returning one of the input Strings.
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	toStringOnOff(boolean bool) Converts a boolean to a String returning 'on' or 'off'.
static String	toStringOnOff(Boolean bool) Converts a Boolean to a String returning 'on', 'off', or null.
static String	toStringTrueFalse(boolean bool) Converts a boolean to a String returning 'true' or 'false'.
static String	toStringTrueFalse(Boolean bool) Converts a Boolean to a String returning 'true', 'false', or null.
static String	toStringYesNo(boolean bool) Converts a boolean to a String returning 'yes' or 'no'.
static String	toStringYesNo(Boolean bool) Converts a Boolean to a String returning 'yes', 'no', or null.
static boolean	xor(boolean[] array) Performs an xor on a set of booleans.
static Boolean	xor(Boolean[] array) Performs an xor on an array of Booleans.

Methods inherited from class java.lang.Object

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

Constructor Detail

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 Detail

negate

public static Boolean negate(Boolean bool)

Negates the specified boolean.

If null is passed in, null will be returned.

   BooleanUtils.negate(Boolean.TRUE)  = Boolean.FALSE;
   BooleanUtils.negate(Boolean.FALSE) = Boolean.TRUE;
   BooleanUtils.negate(null)          = null;
 

Parameters:

bool - the Boolean to negate, may be null

Returns:

the negated Boolean, or null if null input

isTrue

public static boolean isTrue(Boolean bool)

Is a Boolean value true, handling null.

   BooleanUtils.isTrue(Boolean.TRUE)  = true
   BooleanUtils.isTrue(Boolean.FALSE) = false
   BooleanUtils.isTrue(null)          = false
 

Parameters:

bool - the boolean to convert

Returns:

true only if the input is non-null and true

Since:

2.1

isFalse

public static boolean isFalse(Boolean bool)

Is a Boolean value false, handling null.

   BooleanUtils.isFalse(Boolean.TRUE)  = false
   BooleanUtils.isFalse(Boolean.FALSE) = true
   BooleanUtils.isFalse(null)          = false
 

Parameters:

bool - the boolean to convert

Returns:

true only if the input is non-null and false

Since:

2.1

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.

   BooleanUtils.toBooleanObject(false) = Boolean.FALSE
   BooleanUtils.toBooleanObject(true)  = Boolean.TRUE
 

Parameters:

bool - the boolean to convert

Returns:

Boolean.TRUE or Boolean.FALSE as appropriate

toBoolean

public static boolean toBoolean(Boolean bool)

Converts a Boolean to a boolean handling null by returning false.

   BooleanUtils.toBoolean(Boolean.TRUE)  = true
   BooleanUtils.toBoolean(Boolean.FALSE) = false
   BooleanUtils.toBoolean(null)          = false
 

Parameters:

bool - the boolean to convert

Returns:

true or false, null returns false

toBooleanDefaultIfNull

public static boolean toBooleanDefaultIfNull(Boolean bool,
                                             boolean valueIfNull)

Converts a Boolean to a boolean handling null.

   BooleanUtils.toBooleanDefaultIfNull(Boolean.TRUE, false) = true
   BooleanUtils.toBooleanDefaultIfNull(Boolean.FALSE, true) = false
   BooleanUtils.toBooleanDefaultIfNull(null, true)          = true
 

Parameters:

bool - the boolean to convert

valueIfNull - the boolean value to return if null

Returns:

true or false

toBoolean

public static boolean toBoolean(int value)

Converts an int to a boolean using the convention that zero is false.

   BooleanUtils.toBoolean(0) = false
   BooleanUtils.toBoolean(1) = true
   BooleanUtils.toBoolean(2) = true
 

Parameters:

value - the int to convert

Returns:

true if non-zero, false if zero

toBooleanObject

public static Boolean toBooleanObject(int value)

Converts an int to a Boolean using the convention that zero is false.

   BooleanUtils.toBoolean(0) = Boolean.FALSE
   BooleanUtils.toBoolean(1) = Boolean.TRUE
   BooleanUtils.toBoolean(2) = Boolean.TRUE
 

Parameters:

value - the int to convert

Returns:

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

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.

   BooleanUtils.toBoolean(new Integer(0))    = Boolean.FALSE
   BooleanUtils.toBoolean(new Integer(1))    = Boolean.TRUE
   BooleanUtils.toBoolean(new Integer(null)) = null
 

Parameters:

value - the Integer to convert

Returns:

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

toBoolean

public static boolean toBoolean(int value,
                                int trueValue,
                                int falseValue)

Converts an int to a boolean specifying the conversion values.

   BooleanUtils.toBoolean(0, 1, 0) = false
   BooleanUtils.toBoolean(1, 1, 0) = true
   BooleanUtils.toBoolean(2, 1, 2) = false
   BooleanUtils.toBoolean(2, 2, 0) = true
 

Parameters:

value - the Integer to convert

trueValue - the value to match for true

falseValue - the value to match for false

Returns:

true or false

Throws:

IllegalArgumentException - if no match

toBoolean

public static boolean toBoolean(Integer value,
                                Integer trueValue,
                                Integer falseValue)

Converts an Integer to a boolean specifying the conversion values.

   BooleanUtils.toBoolean(new Integer(0), new Integer(1), new Integer(0)) = false
   BooleanUtils.toBoolean(new Integer(1), new Integer(1), new Integer(0)) = true
   BooleanUtils.toBoolean(new Integer(2), new Integer(1), new Integer(2)) = false
   BooleanUtils.toBoolean(new Integer(2), new Integer(2), new Integer(0)) = true
   BooleanUtils.toBoolean(null, null, new Integer(0))                     = true
 

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

Throws:

IllegalArgumentException - if no match

toBooleanObject

public static Boolean toBooleanObject(int value,
                                      int trueValue,
                                      int falseValue,
                                      int nullValue)

Converts an int to a Boolean specifying the conversion values.

   BooleanUtils.toBooleanObject(0, 0, 2, 3) = Boolean.TRUE
   BooleanUtils.toBooleanObject(2, 1, 2, 3) = Boolean.FALSE
   BooleanUtils.toBooleanObject(3, 1, 2, 3) = null
 

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

Throws:

IllegalArgumentException - if no match

toBooleanObject

public static Boolean toBooleanObject(Integer value,
                                      Integer trueValue,
                                      Integer falseValue,
                                      Integer nullValue)

Converts an Integer to a Boolean specifying the conversion values.

   BooleanUtils.toBooleanObject(new Integer(0), new Integer(0), new Integer(2), new Integer(3)) = Boolean.TRUE
   BooleanUtils.toBooleanObject(new Integer(2), new Integer(1), new Integer(2), new Integer(3)) = Boolean.FALSE
   BooleanUtils.toBooleanObject(new Integer(3), new Integer(1), new Integer(2), new Integer(3)) = null
 

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

Throws:

IllegalArgumentException - if no match

toInteger

public static int toInteger(boolean bool)

Converts a boolean to an int using the convention that zero is false.

   BooleanUtils.toInteger(true)  = 1
   BooleanUtils.toInteger(false) = 0
 

Parameters:

bool - the boolean to convert

Returns:

one if true, zero if false

toIntegerObject

public static Integer toIntegerObject(boolean bool)

Converts a boolean to an Integer using the convention that zero is false.

   BooleanUtils.toIntegerObject(true)  = new Integer(1)
   BooleanUtils.toIntegerObject(false) = new Integer(0)
 

Parameters:

bool - the boolean to convert

Returns:

one if true, zero if false

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.

   BooleanUtils.toIntegerObject(Boolean.TRUE)  = new Integer(1)
   BooleanUtils.toIntegerObject(Boolean.FALSE) = new Integer(0)
 

Parameters:

bool - the Boolean to convert

Returns:

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

toInteger

public static int toInteger(boolean bool,
                            int trueValue,
                            int falseValue)

Converts a boolean to an int specifying the conversion values.

   BooleanUtils.toInteger(true, 1, 0)  = 1
   BooleanUtils.toInteger(false, 1, 0) = 0
 

Parameters:

bool - the to convert

trueValue - the value to return if true

falseValue - the value to return if false

Returns:

the appropriate value

toInteger

public static int toInteger(Boolean bool,
                            int trueValue,
                            int falseValue,
                            int nullValue)

Converts a Boolean to an int specifying the conversion values.

   BooleanUtils.toInteger(Boolean.TRUE, 1, 0, 2)  = 1
   BooleanUtils.toInteger(Boolean.FALSE, 1, 0, 2) = 0
   BooleanUtils.toInteger(null, 1, 0, 2)          = 2
 

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

toIntegerObject

public static Integer toIntegerObject(boolean bool,
                                      Integer trueValue,
                                      Integer falseValue)

Converts a boolean to an Integer specifying the conversion values.

   BooleanUtils.toIntegerObject(true, new Integer(1), new Integer(0))  = new Integer(1)
   BooleanUtils.toIntegerObject(false, new Integer(1), new Integer(0)) = new Integer(0)
 

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

toIntegerObject

public static Integer toIntegerObject(Boolean bool,
                                      Integer trueValue,
                                      Integer falseValue,
                                      Integer nullValue)

Converts a Boolean to an Integer specifying the conversion values.

   BooleanUtils.toIntegerObject(Boolean.TRUE, new Integer(1), new Integer(0), new Integer(2))  = new Integer(1)
   BooleanUtils.toIntegerObject(Boolean.FALSE, new Integer(1), new Integer(0), new Integer(2)) = new Integer(0)
   BooleanUtils.toIntegerObject(null, new Integer(1), new Integer(0), new Integer(2))          = new Integer(2)
 

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

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.

   BooleanUtils.toBooleanObject(null)    = null
   BooleanUtils.toBooleanObject("true")  = Boolean.TRUE
   BooleanUtils.toBooleanObject("false") = Boolean.FALSE
   BooleanUtils.toBooleanObject("on")    = Boolean.TRUE
   BooleanUtils.toBooleanObject("ON")    = Boolean.TRUE
   BooleanUtils.toBooleanObject("off")   = Boolean.FALSE
   BooleanUtils.toBooleanObject("oFf")   = Boolean.FALSE
   BooleanUtils.toBooleanObject("blue")  = null
 

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.

   BooleanUtils.toBooleanObject("true", "true", "false", "null")  = Boolean.TRUE
   BooleanUtils.toBooleanObject("false", "true", "false", "null") = Boolean.FALSE
   BooleanUtils.toBooleanObject("null", "true", "false", "null")  = null
 

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

toBoolean

public static boolean toBoolean(String str)

Converts a String to a boolean (optimised for performance).

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

This method performs 4 times faster (JDK1.4) than Boolean.valueOf(String). However, this method accepts 'on' and 'yes' as true values.

   BooleanUtils.toBoolean(null)    = false
   BooleanUtils.toBoolean("true")  = true
   BooleanUtils.toBoolean("TRUE")  = true
   BooleanUtils.toBoolean("tRUe")  = true
   BooleanUtils.toBoolean("on")    = true
   BooleanUtils.toBoolean("yes")   = true
   BooleanUtils.toBoolean("false") = false
   BooleanUtils.toBoolean("x gti") = false
 

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.

   BooleanUtils.toBoolean("true", "true", "false")  = true
   BooleanUtils.toBoolean("false", "true", "false") = false
 

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

Throws:

IllegalArgumentException - if the String doesn't match

toStringTrueFalse

public static String toStringTrueFalse(Boolean bool)

Converts a Boolean to a String returning 'true', 'false', or null.

   BooleanUtils.toStringTrueFalse(Boolean.TRUE)  = "true"
   BooleanUtils.toStringTrueFalse(Boolean.FALSE) = "false"
   BooleanUtils.toStringTrueFalse(null)          = null;
 

Parameters:

bool - the Boolean to check

Returns:

'true', 'false', or null

toStringOnOff

public static String toStringOnOff(Boolean bool)

Converts a Boolean to a String returning 'on', 'off', or null.

   BooleanUtils.toStringOnOff(Boolean.TRUE)  = "on"
   BooleanUtils.toStringOnOff(Boolean.FALSE) = "off"
   BooleanUtils.toStringOnOff(null)          = null;
 

Parameters:

bool - the Boolean to check

Returns:

'on', 'off', or null

toStringYesNo

public static String toStringYesNo(Boolean bool)

Converts a Boolean to a String returning 'yes', 'no', or null.

   BooleanUtils.toStringYesNo(Boolean.TRUE)  = "yes"
   BooleanUtils.toStringYesNo(Boolean.FALSE) = "no"
   BooleanUtils.toStringYesNo(null)          = null;
 

Parameters:

bool - the Boolean to check

Returns:

'yes', 'no', or null

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.

   BooleanUtils.toString(Boolean.TRUE, "true", "false", null)   = "true"
   BooleanUtils.toString(Boolean.FALSE, "true", "false", null)  = "false"
   BooleanUtils.toString(null, "true", "false", null)           = null;
 

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

toStringTrueFalse

public static String toStringTrueFalse(boolean bool)

Converts a boolean to a String returning 'true' or 'false'.

   BooleanUtils.toStringTrueFalse(true)   = "true"
   BooleanUtils.toStringTrueFalse(false)  = "false"
 

Parameters:

bool - the Boolean to check

Returns:

'true', 'false', or null

toStringOnOff

public static String toStringOnOff(boolean bool)

Converts a boolean to a String returning 'on' or 'off'.

   BooleanUtils.toStringOnOff(true)   = "on"
   BooleanUtils.toStringOnOff(false)  = "off"
 

Parameters:

bool - the Boolean to check

Returns:

'on', 'off', or null

toStringYesNo

public static String toStringYesNo(boolean bool)

Converts a boolean to a String returning 'yes' or 'no'.

   BooleanUtils.toStringYesNo(true)   = "yes"
   BooleanUtils.toStringYesNo(false)  = "no"
 

Parameters:

bool - the Boolean to check

Returns:

'yes', 'no', or null

toString

public static String toString(boolean bool,
                              String trueString,
                              String falseString)

Converts a boolean to a String returning one of the input Strings.

   BooleanUtils.toString(true, "true", "false")   = "true"
   BooleanUtils.toString(false, "true", "false")  = "false"
 

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

xor

public static boolean xor(boolean[] array)

Performs an xor on a set of booleans.

   BooleanUtils.xor(new boolean[] { true, true })   = false
   BooleanUtils.xor(new boolean[] { false, false }) = false
   BooleanUtils.xor(new boolean[] { true, false })  = true
 

Parameters:

array - an array of booleans

Returns:

true if the xor is successful.

Throws:

IllegalArgumentException - if array is null

IllegalArgumentException - if array is empty.

xor

public static Boolean xor(Boolean[] array)

Performs an xor on an array of Booleans.

   BooleanUtils.xor(new Boolean[] { Boolean.TRUE, Boolean.TRUE })   = Boolean.FALSE
   BooleanUtils.xor(new Boolean[] { Boolean.FALSE, Boolean.FALSE }) = Boolean.FALSE
   BooleanUtils.xor(new Boolean[] { Boolean.TRUE, Boolean.FALSE })  = Boolean.TRUE
 

Parameters:

array - an array of Booleans

Returns:

true if the xor is successful.

Throws:

IllegalArgumentException - if array is null

IllegalArgumentException - if array is empty.

IllegalArgumentException - if array contains a null