ch.jalu.configme.beanmapper

Class Mapper

java.lang.Object

ch.jalu.configme.beanmapper.Mapper

public class Mapper
extends Object

Maps a section of a property resource to the provided JavaBean class. The mapping is based on the bean's properties, whose names must correspond with the names in the property resource. For example, if a JavaBean class has a property length and should be mapped from the property resource's value at path definition, the mapper will look up definition.length to get the value for the JavaBean property.

Classes must be JavaBeans. These are simple classes with private fields, accompanied with getters and setters. The mapper only considers properties which have both a getter and a setter method. Any Java class without at least one property with both a getter and a setter is not considered as a JavaBean class. Such classes can be supported by implementing a custom Transformer that performs the conversion from the property resource to an object of the class' type.

Recursion: the mapping of values to a JavaBean is performed recursively, i.e. a JavaBean may have other JavaBeans as fields at any arbitrary "depth."

Collections are only supported if they are explicitly typed, i.e. a field of List<String> is supported but List<?> and List<T extends Number> are not supported. Specifically, you may only declare fields of type List or Set, or a parent type (Collection or Iterable). Fields of type Map are supported also, with similar limitations. Additionally, maps may only have String as key type, but no restrictions are imposed on the value type.

JavaBeans may have optional fields. If the mapper cannot map the property resource value to the corresponding field, it only treats it as a failure if the field's value is null. If the field has a default value assigned to it on initialization, the default value remains and the mapping process continues. A JavaBean field whose value is null signifies a failure and stops the mapping process immediately.

Constructor Summary

Constructors

Constructor and Description
Mapper() Creates a new JavaBean mapper with the default configuration.
Mapper(MappingErrorHandler mappingErrorHandler, BeanDescriptionFactory beanDescriptionFactory, Transformer... transformers) Creates a new JavaBean mapper with the given elements.

Method Summary

Modifier and Type	Method and Description
<T> T	convertToBean(String path, PropertyResource resource, Class<T> clazz) Converts the value in the property resource at the given path to the provided beans class.
protected <T> T	convertToBean(TypeInformation<T> type, Object value, MappingContext context) Converts the provided value to the requested JavaBeans class if possible.
protected Object	getPropertyValue(TypeInformation typeInformation, Object value, MappingContext context) Returns a value of type clazz based on the provided value if possible.
Collection<BeanPropertyDescription>	getWritableProperties(Class<?> clazz) Returns the properties of the given bean class that need to be considered when constructing objects.
protected Collection<?>	processCollection(TypeInformation<?> type, Object value, MappingContext context)
protected Map	processMap(TypeInformation<?> type, Object value, MappingContext context)
protected Object	processTransformers(TypeInformation typeInformation, Object value)

Methods inherited from class java.lang.Object

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

Constructor Detail

Mapper

public Mapper()

Creates a new JavaBean mapper with the default configuration.

Mapper

public Mapper(MappingErrorHandler mappingErrorHandler,
              BeanDescriptionFactory beanDescriptionFactory,
              Transformer... transformers)

Creates a new JavaBean mapper with the given elements.

Parameters:

mappingErrorHandler - handler to use for mapping errors

beanDescriptionFactory - factory to get bean property descriptions for classes

transformers - the transformers to use for mapping values

See Also:

Transformers.getDefaultTransformers()

Method Detail

convertToBean

@Nullable
public <T> T convertToBean(String path,
                                     PropertyResource resource,
                                     Class<T> clazz)

Converts the value in the property resource at the given path to the provided beans class.

Type Parameters:

T - the bean type

Parameters:

path - the path to convert from

resource - the property resource to read from

clazz - the JavaBean class

Returns:

the converted bean, or null if not possible

getPropertyValue

@Nullable
protected Object getPropertyValue(TypeInformation typeInformation,
                                            @Nullable
                                            Object value,
                                            MappingContext context)

Returns a value of type clazz based on the provided value if possible.

Parameters:

typeInformation - type information

value - the value to convert from

context - the mapping context

Returns:

the converted value, or null if not possible

processCollection

@Nullable
protected Collection<?> processCollection(TypeInformation<?> type,
                                                    Object value,
                                                    MappingContext context)

processMap

@Nullable
protected Map processMap(TypeInformation<?> type,
                                   Object value,
                                   MappingContext context)

processTransformers

@Nullable
protected Object processTransformers(TypeInformation typeInformation,
                                               Object value)

convertToBean

@Nullable
protected <T> T convertToBean(TypeInformation<T> type,
                                        Object value,
                                        MappingContext context)

Converts the provided value to the requested JavaBeans class if possible.

Type Parameters:

T - the JavaBean type

Parameters:

type - type information

value - the value from the property resource

context - the mapping context

Returns:

the converted value, or null if not possible

getWritableProperties

public Collection<BeanPropertyDescription> getWritableProperties(Class<?> clazz)

Returns the properties of the given bean class that need to be considered when constructing objects.

Parameters:

clazz - the class to get the bean properties from

Returns:

relevant properties