org.apache.commons.beanutils.converters

Class BooleanConverter

Implemented Interfaces:
Converter

public final class BooleanConverter
extends AbstractConverter

Converter implementaion that handles conversion to and from Boolean objects. Converter implementaion that handles conversion to and from java.lang.Boolean objects.

Can be configured to either return a default value or throw a ConversionException if a conversion error occurs.

By default any object whose string representation is one of the values {"yes", "y", "true", "on", "1"} is converted to Boolean.TRUE, and string representations {"no", "n", "false", "off", "0"} are converted to Boolean.FALSE. The recognised true/false strings can be changed by:

  String[] trueStrings = {"oui", "o", "1"};
  String[] falseStrings = {"non", "n", "0"};
  Converter bc = new BooleanConverter(trueStrings, falseStrings);
  ConvertUtils.register(bc, Boolean.class);
  ConvertUtils.register(bc, Boolean.TYPE);
 
In addition, it is recommended that the BooleanArrayConverter also be modified to recognise the same set of values:
   Converter bac = new BooleanArrayConverter(bc, BooleanArrayConverter.NO_DEFAULT);
   ConvertUtils.register(bac, bac.MODEL);
 

Case is ignored when converting values to true or false.

Version:
$Revision: 555845 $ $Date: 2007-07-13 03:52:05 +0100 (Fri, 13 Jul 2007) $
Author:
Craig R. McClanahan
Since:
1.3

Field Summary

static Object
NO_DEFAULT
Deprecated. Use constructors without default value.
private String[]
falseStrings
The set of strings that are known to map to Boolean.FALSE.
private String[]
trueStrings
The set of strings that are known to map to Boolean.TRUE.

Fields inherited from class org.apache.commons.beanutils.converters.AbstractConverter

DEFAULT_CONFIG_MSG, PACKAGE, defaultType, defaultValue, log, useDefault

Constructor Summary

BooleanConverter()
Create a Converter that will throw a ConversionException if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.
BooleanConverter(Object defaultValue)
Create a Converter that will return the specified default value if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.
BooleanConverter(String[] trueStrings, String[] falseStrings)
Create a Converter that will throw a ConversionException if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.
BooleanConverter(String[] trueStrings, String[] falseStrings, Object defaultValue)
Create a Converter that will return the specified default value if a conversion error occurs.

Method Summary

protected Object
convertToType(Class type, Object value)
Convert the specified input object into an output object of the specified type.
private static String[]
copyStrings(String[] src)
This method creates a copy of the provided array, and ensures that all the strings in the newly created array contain only lower-case letters.

Methods inherited from class org.apache.commons.beanutils.converters.AbstractConverter

convert, convertArray, convertToString, convertToType, getDefault, getDefaultType, handleError, handleMissing, isUseDefault, log, primitive, setDefaultValue, toString, toString

Field Details

NO_DEFAULT

public static final Object NO_DEFAULT

Deprecated. Use constructors without default value.

This is a special reference that can be passed as the "default object" to the constructor to indicate that no default is desired. Note that the value 'null' cannot be used for this purpose, as the caller may want a null to be returned as the default.

falseStrings

private String[] falseStrings
The set of strings that are known to map to Boolean.FALSE.

trueStrings

private String[] trueStrings
The set of strings that are known to map to Boolean.TRUE.

Constructor Details

BooleanConverter

public BooleanConverter()
Create a Converter that will throw a ConversionException if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.

BooleanConverter

public BooleanConverter(Object defaultValue)
Create a Converter that will return the specified default value if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.
Parameters:
defaultValue - The default value to be returned if the value being converted is not recognised. This value may be null, in which case null will be returned on conversion failure. When non-null, it is expected that this value will be either Boolean.TRUE or Boolean.FALSE. The special value BooleanConverter.NO_DEFAULT can also be passed here, in which case this constructor acts like the no-argument one.

BooleanConverter

public BooleanConverter(String[] trueStrings,
                        String[] falseStrings)
Create a Converter that will throw a ConversionException if a conversion error occurs, ie the string value being converted is not one of the known true strings, nor one of the known false strings.

The provided string arrays are copied, so that changes to the elements of the array after this call is made do not affect this object.

Parameters:
trueStrings - is the set of strings which should convert to the value Boolean.TRUE. The value null must not be present. Case is ignored.
falseStrings - is the set of strings which should convert to the value Boolean.TRUE. The value null must not be present. Case is ignored.

BooleanConverter

public BooleanConverter(String[] trueStrings,
                        String[] falseStrings,
                        Object defaultValue)
Create a Converter that will return the specified default value if a conversion error occurs.

The provided string arrays are copied, so that changes to the elements of the array after this call is made do not affect this object.

Parameters:
trueStrings - is the set of strings which should convert to the value Boolean.TRUE. The value null must not be present. Case is ignored.
falseStrings - is the set of strings which should convert to the value Boolean.TRUE. The value null must not be present. Case is ignored.
defaultValue - The default value to be returned if the value being converted is not recognised. This value may be null, in which case null will be returned on conversion failure. When non-null, it is expected that this value will be either Boolean.TRUE or Boolean.FALSE. The special value BooleanConverter.NO_DEFAULT can also be passed here, in which case an exception will be thrown on conversion failure.

Method Details

convertToType

protected Object convertToType(Class type,
                               Object value)
            throws Throwable
Convert the specified input object into an output object of the specified type.
Overrides:
convertToType in interface AbstractConverter
Parameters:
type - is the type to which this value should be converted. In the case of this BooleanConverter class, this value is ignored.
value - is the input value to be converted. The toString method shall be invoked on this object, and the result compared (ignoring case) against the known "true" and "false" string values.
Returns:
Boolean.TRUE if the value was a recognised "true" value, Boolean.FALSE if the value was a recognised "false" value, or the default value if the value was not recognised and the constructor was provided with a default value.

copyStrings

private static String[] copyStrings(String[] src)
This method creates a copy of the provided array, and ensures that all the strings in the newly created array contain only lower-case letters.

Using this method to copy string arrays means that changes to the src array do not modify the dst array.


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