de.vandermeer.skb.base.utils

Class Skb_ObjectUtils

java.lang.Object

de.vandermeer.skb.base.utils.Skb_ObjectUtils

public abstract class Skb_ObjectUtils
extends Object

Object converters.

Version:

v0.0.3 build 150618 (18-Jun-15) for Java 1.8

Author:

Sven van der Meer <vdmeer.sven@mykolab.com>

Constructor Summary

Constructors

Constructor and Description
Skb_ObjectUtils()

Method Summary

Modifier and Type	Method and Description
static <T> T	CONVERT(Object value, Class<T> clazz) Type safe casting or conversion from Object to target class, special processing for Object[] and Collections.
static <T> T	CONVERT(Object value, Class<T> clazz, T nullValue, T falseValue) Type safe casting or conversion from Object to target class, special processing for Object[] and Collections.
static <T> T	CONVERT(Object value, Class<T> clazz, T nullValue, T falseValue, boolean collFirst) Type safe casting or conversion from Object to target class, with optional special processing for Object[] and Collections.
static Skb_Transformer<String,Boolean>	OBJECT_TO_BOOLEAN() Returns a transformer that takes a string and returns a boolean value, or null.
static <T> Skb_Transformer<Object,T>	OBJECT_TO_TARGET(Class<T> clazz, T nullValue, T falseValue, boolean collFirst) Type safe transformation from Object to target class, with optional special processing for Object[] and Collections.

Methods inherited from class java.lang.Object

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

Constructor Detail

Skb_ObjectUtils

public Skb_ObjectUtils()

Method Detail

OBJECT_TO_BOOLEAN

public static final Skb_Transformer<String,Boolean> OBJECT_TO_BOOLEAN()

Returns a transformer that takes a string and returns a boolean value, or null. The transformer returns true if the string is "true" or "on" and false if the string is "false" or "off" (all string are tested ignoring case).

Returns:

transformer that takes an object and returns a boolean

OBJECT_TO_TARGET

public static final <T> Skb_Transformer<Object,T> OBJECT_TO_TARGET(Class<T> clazz,
                                                                   T nullValue,
                                                                   T falseValue,
                                                                   boolean collFirst)

Type safe transformation from Object to target class, with optional special processing for Object[] and Collections. The conversion is done in the following sequence:

• If value is null, the nullValue will be returned.
• If the requested class is an object array (clazz==Object[]), then the return is value (if value is an Object[]) or Collection.toArray() (if value is a Collection). In all other cases the process proceeds
• If collFist is set to true and value is a Collection, the first value of this collection will be used for the further process
• Now another null test returning nullValue if value is null
• Next test if the clazz is an instance of value.class. If true, value will be returned
• Next try for some standard type conversions for value, namely
  • If clazz is an instance of Boolean and value is "true" or "on" (case insensitive), then return Boolean(true)
  • If clazz is an instance of Boolean and value is "false" or "off" (case insensitive), then return Boolean(false)
  • If clazz is an instance of Integer then try to return Integer.valueOf(value.toString).
  • If clazz is an instance of Double then try to return Double.valueOf(value.toString).
  • If clazz is an instance of Long then try to return Long.valueOf(value.toString).
• The last option is to return valueFalse to indicate that no test was successful

This method does suppress warnings for "unchecked" castings, because a casting from any concrete return type to T is unsafe. Because all actual castings follow an explicit type check, this suppression should have not negative impact (i.e. there are no ClassCastExceptions).

Type Parameters:

T - target class for the transformation

Parameters:

clazz - the requested type of the return value, required for initialisation

nullValue - the value to be used if a null test succeeds

falseValue - the value to be used in case no test succeeds

collFirst - if set true, collections will be processed and the first element returned, no special collection processing otherwise

Returns:

transformer that returns a value of type T if a conversion was successful, nullValue if null was tested successfully, falseValue in all other cases

CONVERT

public static final <T> T CONVERT(Object value,
                                  Class<T> clazz)

Type safe casting or conversion from Object to target class, special processing for Object[] and Collections. This is a convenient method for CONVERT(Object, Class, Object, Object, boolean) with both return values set to null and the last argument set to true (i.e. special processing of collections).

Type Parameters:

T - type of the return object

Parameters:

value - the value that should be converted

clazz - the requested type of the return value, needed for initialisation

Returns:

a value of type T if a conversion was successful, nullValue if null was tested successfully, falseValue in all other cases

See Also:

CONVERT(Object, Class, Object, Object, boolean)

CONVERT

public static final <T> T CONVERT(Object value,
                                  Class<T> clazz,
                                  T nullValue,
                                  T falseValue)

Type safe casting or conversion from Object to target class, special processing for Object[] and Collections. This is a convenient method for CONVERT(Object, Class, Object, Object, boolean) with the last argument set to true (i.e. special processing of collections).

Type Parameters:

T - type of the return object

Parameters:

value - the value that should be converted

clazz - the requested type of the return value, needed for initialisation

nullValue - the value to be used if a null test succeeds

falseValue - the value to be used in case no test succeeds

Returns:

a value of type T if a conversion was successful, nullValue if null was tested successfully, falseValue in all other cases

See Also:

CONVERT(Object, Class, Object, Object, boolean)

CONVERT

public static final <T> T CONVERT(Object value,
                                  Class<T> clazz,
                                  T nullValue,
                                  T falseValue,
                                  boolean collFirst)

Type safe casting or conversion from Object to target class, with optional special processing for Object[] and Collections.

Type Parameters:

T - type of the return object

Parameters:

value - the value that should be converted

clazz - the requested type of the return value, needed for initialisation

nullValue - the value to be used if a null test succeeds

falseValue - the value to be used in case no test succeeds

collFirst - if set true, collections will be processed and the first element returned, no special collection processing otherwise

Returns:

a value of type T if a conversion was successful, nullValue if null was tested successfully, falseValue in all other cases

See Also:

OBJECT_TO_TARGET(java.lang.Class<T>, T, T, boolean)