org.bremersee.comparator

Interface ValueExtractor

All Known Implementing Classes:

DefaultValueExtractor

public interface ValueExtractor

The value extractor finds the value of a given field name or path by reflection.

Author:

Christian Bremer

Method Summary

Modifier and Type	Method and Description
default Optional<Field>	findField(Class<?> clazz, String name) Find field with the given name of the specified class.
default Optional<Field>	findField(Class<?> clazz, String name, Class<?> type) Find the field with the given name of the specified class.
default Optional<Method>	findMethod(Class<?> clazz, String name) Find the method with the given name and no parameters of the specified class.
default Optional<Method>	findMethod(Class<?> clazz, String name, Class<?>... paramTypes) Find the method with the given name and parameters of the specified class.
Object	findValue(Object obj, String field) Find the value of the given add name or path of the given object.
default String[]	getPossibleMethodNames(String name) Get possible method names of the given field name.
default Object	invoke(Field field, Object obj) Invoke the given field on the given object.
default Object	invoke(Method method, Object obj) Invoke the given method on the given object.

Method Detail

findValue

Object findValue(Object obj,
                 String field)

Find the value of the given add name or path of the given object.

Parameters:

obj - the object

field - the field name or path

Returns:

the object

Throws:

ValueExtractorException - if no add nor method is found

findField

default Optional<Field> findField(Class<?> clazz,
                                  String name)

Find field with the given name of the specified class.

Parameters:

clazz - the class

name - the field name

Returns:

the field

findField

default Optional<Field> findField(Class<?> clazz,
                                  String name,
                                  Class<?> type)

Find the field with the given name of the specified class.

Parameters:

clazz - the class

name - the field name

type - the type of the field

Returns:

the field

getPossibleMethodNames

default String[] getPossibleMethodNames(String name)

Get possible method names of the given field name. The default implementation returns the field name, it's getter for an object and a primitive boolean.

If 'firstName' is given for example, 'firstName', 'getFirstName' and 'isFirstName' will be returned.

Parameters:

name - the field name

Returns:

the possible method names

findMethod

default Optional<Method> findMethod(Class<?> clazz,
                                    String name)

Find the method with the given name and no parameters of the specified class.

Parameters:

clazz - the class

name - the method name

Returns:

the method

findMethod

default Optional<Method> findMethod(Class<?> clazz,
                                    String name,
                                    Class<?>... paramTypes)

Find the method with the given name and parameters of the specified class.

Parameters:

clazz - the class

name - the method name

paramTypes - the parameter types

Returns:

the method

invoke

default Object invoke(Method method,
                      Object obj)

Invoke the given method on the given object. If the method is not accessible, setAccessible(true) will be called.

Parameters:

method - the method

obj - the object

Returns:

the return value of the method

Throws:

ValueExtractorException - if a IllegalAccessException or a InvocationTargetException occurs

invoke

default Object invoke(Field field,
                      Object obj)

Invoke the given field on the given object. If the field is not accessible, setAccessible(true) will be called.

Parameters:

field - the field

obj - the object

Returns:

the value of the field

Throws:

ValueExtractorException - if a IllegalAccessException occurs