org.apache.commons.beanutils

Class ConvertUtilsBean

public class ConvertUtilsBean extends Object

Utility methods for converting String scalar values to objects of the specified Class, String arrays to arrays of the specified Class. The actual Converter instance to be used can be registered for each possible destination Class. Unless you override them, standard Converter instances are provided for all of the following destination Classes:

For backwards compatibility, the standard Converters for primitive types (and the corresponding wrapper classes) return a defined default value when a conversion error occurs. If you prefer to have a ConversionException thrown instead, replace the standard Converter instances with instances created with the zero-arguments constructor. For example, to cause the Converters for integers to throw an exception on conversion errors, you could do this:

   // No-args constructor gets the version that throws exceptions
   Converter myConverter =
    new org.apache.commons.beanutils.converter.IntegerConverter();
   ConvertUtils.register(myConverter, Integer.TYPE);    // Native type
   ConvertUtils.register(myConverter, Integer.class);   // Wrapper class
 

Converters generally treat null input as if it were invalid input, ie they return their default value if one was specified when the converter was constructed, and throw an exception otherwise. If you prefer nulls to be preserved for converters that are converting to objects (not primitives) then register a converter as above, passing a default value of null to the converter constructor (and of course registering that converter only for the .class target).

When a converter is listed above as having no default value, then that converter will throw an exception when passed null or an invalid value as its input. In particular, by default the BigInteger and BigDecimal converters have no default (and are therefore somewhat inconsistent with the other numerical converters which all have zero as their default).

Converters that generate arrays of each of the primitive types are also automatically configured (including String[]). When passed null or invalid input, these return an empty array (not null). See class AbstractArrayConverter for the supported input formats for these converters.

Since: 1.7

Version: $Revision: 745079 $ $Date: 2009-02-17 14:04:10 +0000 (Tue, 17 Feb 2009) $

Author: Craig R. McClanahan Ralph Schaer Chris Audley James Strachan

Constructor Summary
ConvertUtilsBean()
Construct a bean with standard converters registered
Method Summary
Stringconvert(Object value)
Convert the specified value into a String.
Objectconvert(String value, Class clazz)
Convert the specified value to an object of the specified class (if possible).
Objectconvert(String[] values, Class clazz)
Convert an array of specified values to an array of objects of the specified class (if possible).
Objectconvert(Object value, Class targetType)

Convert the value to an object of the specified class (if possible).

voidderegister()
Remove all registered Converters, and re-establish the standard Converters.
voidderegister(Class clazz)
Remove any registered Converter for the specified destination Class.
booleangetDefaultBoolean()
Gets the default value for Boolean conversions.
bytegetDefaultByte()
Gets the default value for Byte conversions.
chargetDefaultCharacter()
Gets the default value for Character conversions.
doublegetDefaultDouble()
Gets the default value for Double conversions.
floatgetDefaultFloat()
Gets the default value for Float conversions.
intgetDefaultInteger()
Gets the default value for Integer conversions.
longgetDefaultLong()
Gets the default value for Long conversions.
shortgetDefaultShort()
Gets the default value for Short conversions.
protected static ConvertUtilsBeangetInstance()
Get singleton instance
Converterlookup(Class clazz)
Look up and return any registered Converter for the specified destination class; if there is no registered Converter, return null.
Converterlookup(Class sourceType, Class targetType)
Look up and return any registered Converter for the specified source and destination class; if there is no registered Converter, return null.
voidregister(boolean throwException, boolean defaultNull, int defaultArraySize)
Register the provided converters with the specified defaults.
voidregister(Converter converter, Class clazz)
Register a custom Converter for the specified destination Class, replacing any previously registered Converter.
voidsetDefaultBoolean(boolean newDefaultBoolean)
Sets the default value for Boolean conversions.
voidsetDefaultByte(byte newDefaultByte)
Sets the default value for Byte conversions.
voidsetDefaultCharacter(char newDefaultCharacter)
Sets the default value for Character conversions.
voidsetDefaultDouble(double newDefaultDouble)
Sets the default value for Double conversions.
voidsetDefaultFloat(float newDefaultFloat)
Sets the default value for Float conversions.
voidsetDefaultInteger(int newDefaultInteger)
Sets the default value for Integer conversions.
voidsetDefaultLong(long newDefaultLong)
Sets the default value for Long conversions.
voidsetDefaultShort(short newDefaultShort)
Sets the default value for Short conversions.

Constructor Detail

ConvertUtilsBean

public ConvertUtilsBean()
Construct a bean with standard converters registered

Method Detail

convert

public String convert(Object value)
Convert the specified value into a String. If the specified value is an array, the first element (converted to a String) will be returned. The registered Converter for the java.lang.String class will be used, which allows applications to customize Object->String conversions (the default implementation simply uses toString()).

Parameters: value Value to be converted (may be null)

Returns: The converted String value

convert

public Object convert(String value, Class clazz)
Convert the specified value to an object of the specified class (if possible). Otherwise, return a String representation of the value.

Parameters: value Value to be converted (may be null) clazz Java class to be converted to

Returns: The converted value

Throws: ConversionException if thrown by an underlying Converter

convert

public Object convert(String[] values, Class clazz)
Convert an array of specified values to an array of objects of the specified class (if possible). If the specified Java class is itself an array class, this class will be the type of the returned value. Otherwise, an array will be constructed whose component type is the specified class.

Parameters: values Array of values to be converted clazz Java array or element class to be converted to

Returns: The converted value

Throws: ConversionException if thrown by an underlying Converter

convert

public Object convert(Object value, Class targetType)

Convert the value to an object of the specified class (if possible).

Parameters: value Value to be converted (may be null) targetType Class of the value to be converted to

Returns: The converted value

Throws: ConversionException if thrown by an underlying Converter

deregister

public void deregister()
Remove all registered Converters, and re-establish the standard Converters.

deregister

public void deregister(Class clazz)
Remove any registered Converter for the specified destination Class.

Parameters: clazz Class for which to remove a registered Converter

getDefaultBoolean

public boolean getDefaultBoolean()

Deprecated: Register replacement converters for Boolean.TYPE and Boolean.class instead

Gets the default value for Boolean conversions.

Returns: The default Boolean value

getDefaultByte

public byte getDefaultByte()

Deprecated: Register replacement converters for Byte.TYPE and Byte.class instead

Gets the default value for Byte conversions.

Returns: The default Byte value

getDefaultCharacter

public char getDefaultCharacter()

Deprecated: Register replacement converters for Character.TYPE and Character.class instead

Gets the default value for Character conversions.

Returns: The default Character value

getDefaultDouble

public double getDefaultDouble()

Deprecated: Register replacement converters for Double.TYPE and Double.class instead

Gets the default value for Double conversions.

Returns: The default Double value

getDefaultFloat

public float getDefaultFloat()

Deprecated: Register replacement converters for Float.TYPE and Float.class instead

Gets the default value for Float conversions.

Returns: The default Float value

getDefaultInteger

public int getDefaultInteger()

Deprecated: Register replacement converters for Integer.TYPE and Integer.class instead

Gets the default value for Integer conversions.

Returns: The default Integer value

getDefaultLong

public long getDefaultLong()

Deprecated: Register replacement converters for Long.TYPE and Long.class instead

Gets the default value for Long conversions.

Returns: The default Long value

getDefaultShort

public short getDefaultShort()

Deprecated: Register replacement converters for Short.TYPE and Short.class instead

Gets the default value for Short conversions.

Returns: The default Short value

getInstance

protected static ConvertUtilsBean getInstance()
Get singleton instance

Returns: The singleton instance

lookup

public Converter lookup(Class clazz)
Look up and return any registered Converter for the specified destination class; if there is no registered Converter, return null.

Parameters: clazz Class for which to return a registered Converter

Returns: The registered Converter or null if not found

lookup

public Converter lookup(Class sourceType, Class targetType)
Look up and return any registered Converter for the specified source and destination class; if there is no registered Converter, return null.

Parameters: sourceType Class of the value being converted targetType Class of the value to be converted to

Returns: The registered Converter or null if not found

register

public void register(boolean throwException, boolean defaultNull, int defaultArraySize)
Register the provided converters with the specified defaults.

Parameters: throwException true if the converters should throw an exception when a conversion error occurs, otherwise false if a default value should be used. defaultNull trueif the standard converters (see ConvertUtilsBean) should use a default value of null, otherwise false. N.B. This values is ignored if throwException is true defaultArraySize The size of the default array value for array converters (N.B. This values is ignored if throwException is true). Specifying a value less than zero causes a null value to be used for the default.

register

public void register(Converter converter, Class clazz)
Register a custom Converter for the specified destination Class, replacing any previously registered Converter.

Parameters: converter Converter to be registered clazz Destination class for conversions performed by this Converter

setDefaultBoolean

public void setDefaultBoolean(boolean newDefaultBoolean)

Deprecated: Register replacement converters for Boolean.TYPE and Boolean.class instead

Sets the default value for Boolean conversions.

Parameters: newDefaultBoolean The default Boolean value

setDefaultByte

public void setDefaultByte(byte newDefaultByte)

Deprecated: Register replacement converters for Byte.TYPE and Byte.class instead

Sets the default value for Byte conversions.

Parameters: newDefaultByte The default Byte value

setDefaultCharacter

public void setDefaultCharacter(char newDefaultCharacter)

Deprecated: Register replacement converters for Character.TYPE and Character.class instead

Sets the default value for Character conversions.

Parameters: newDefaultCharacter The default Character value

setDefaultDouble

public void setDefaultDouble(double newDefaultDouble)

Deprecated: Register replacement converters for Double.TYPE and Double.class instead

Sets the default value for Double conversions.

Parameters: newDefaultDouble The default Double value

setDefaultFloat

public void setDefaultFloat(float newDefaultFloat)

Deprecated: Register replacement converters for Float.TYPE and Float.class instead

Sets the default value for Float conversions.

Parameters: newDefaultFloat The default Float value

setDefaultInteger

public void setDefaultInteger(int newDefaultInteger)

Deprecated: Register replacement converters for Integer.TYPE and Integer.class instead

Sets the default value for Integer conversions.

Parameters: newDefaultInteger The default Integer value

setDefaultLong

public void setDefaultLong(long newDefaultLong)

Deprecated: Register replacement converters for Long.TYPE and Long.class instead

Sets the default value for Long conversions.

Parameters: newDefaultLong The default Long value

setDefaultShort

public void setDefaultShort(short newDefaultShort)

Deprecated: Register replacement converters for Short.TYPE and Short.class instead

Sets the default value for Short conversions.

Parameters: newDefaultShort The default Short value

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