org.apache.shindig.protocol.conversion

Class BeanDelegator

java.lang.Object

org.apache.shindig.protocol.conversion.BeanDelegator

public class BeanDelegator
extends Object

Class to create a delegator (proxy) from an interface to a class. It is used by the GadgetHandler to provide easy separation from interface to actual implementation classes. It uses Java reflection which require the usage of interfaces. The validate function should be used in the test code to validate that all API functions are implemented by the actual data, and it will warn us if actual implementation change and break the API. Delegation support composition, and will create a proxy for fields according To table of classes to proxy.

Since:

2.0.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	BeanDelegator.DelegateInvocationHandler
static class	BeanDelegator.NullClass Fake class that does not have fields or method for field base delegator

Field Summary

Fields

Modifier and Type	Field and Description
static String	NULL Indicate NULL value for a field (To overcome shortcome of immutable map)
static com.google.common.collect.ImmutableSet<Class<?>>	PRIMITIVE_TYPE_CLASSES List of Classes that are considered primitives and are not proxied

Constructor Summary

Constructors

Constructor and Description
BeanDelegator()
BeanDelegator(Map<Class<?>,Class<?>> delegatedClasses, Map<Enum<?>,Enum<?>> enumConvertionMap)

Method Summary

Methods

Modifier and Type	Method and Description
Enum<?>	convertEnum(Enum<?> value)
static Map<Enum<?>,Enum<?>>	createDefaultEnumMap(Class<? extends Enum<?>> sourceEnum, Class<? extends Enum<?>> targetEnum) Utility function to auto generate mapping between two enums that have same values (name) All values in the sourceEnum must have values in targetEnum, otherwise RuntimeException is thrown
Object	createDelegator(Object source) Create a proxy for the real object.
<T> T	createDelegator(Object source, Class<T> apiInterface)
<T> T	createDelegator(Object source, Class<T> apiInterface, Map<String,Object> extraFields)
static Map<String,Object>	normalizeFields(Map<String,Object> original) Convert map of fields to common names and nullable values
static String	normalizeName(String name) Convert field names to common name - no underscore and lower case
static Object	nullable(Object o) Gate a value to use NULL constant instead of null pointer
void	validate() Validate all proxied classes to see that all required functions are implemented.
void	validate(Class<?> dataClass, Class<?> interfaceClass)
static void	validateDelegator(Object o) Validate a delegator object has all fields defined.

Methods inherited from class java.lang.Object

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

Field Detail

NULL

public static final String NULL

Indicate NULL value for a field (To overcome shortcome of immutable map)

See Also:

Constant Field Values

PRIMITIVE_TYPE_CLASSES

public static final com.google.common.collect.ImmutableSet<Class<?>> PRIMITIVE_TYPE_CLASSES

List of Classes that are considered primitives and are not proxied

Constructor Detail

BeanDelegator

public BeanDelegator()

BeanDelegator

public BeanDelegator(Map<Class<?>,Class<?>> delegatedClasses,
             Map<Enum<?>,Enum<?>> enumConvertionMap)

Method Detail

nullable

public static Object nullable(Object o)

Gate a value to use NULL constant instead of null pointer

normalizeName

public static String normalizeName(String name)

Convert field names to common name - no underscore and lower case

normalizeFields

public static Map<String,Object> normalizeFields(Map<String,Object> original)

Convert map of fields to common names and nullable values

createDelegator

public Object createDelegator(Object source)

Create a proxy for the real object.

Parameters:

source - item to proxy

Returns:

proxied object according to map of classes to proxy

createDelegator

public <T> T createDelegator(Object source,
                    Class<T> apiInterface)

createDelegator

public <T> T createDelegator(Object source,
                    Class<T> apiInterface,
                    Map<String,Object> extraFields)

convertEnum

public Enum<?> convertEnum(Enum<?> value)

validate

public void validate()
              throws SecurityException,
                     NoSuchMethodException,
                     NoSuchFieldException

Validate all proxied classes to see that all required functions are implemented. Throws exception if failed validation. Note that it ignore the extra fields support.

Throws:

SecurityException

NoSuchMethodException

NoSuchFieldException

validate

public void validate(Class<?> dataClass,
            Class<?> interfaceClass)
              throws SecurityException,
                     NoSuchMethodException,
                     NoSuchFieldException

Throws:

SecurityException

NoSuchMethodException

NoSuchFieldException

validateDelegator

public static void validateDelegator(Object o)
                              throws IllegalArgumentException,
                                     IllegalAccessException,
                                     InvocationTargetException

Validate a delegator object has all fields defined. With the field list option, classes can be delegated without being complete. This helper method should be used to verify that no field was missed.

Throws:

IllegalArgumentException

IllegalAccessException

InvocationTargetException

createDefaultEnumMap

public static Map<Enum<?>,Enum<?>> createDefaultEnumMap(Class<? extends Enum<?>> sourceEnum,
                                        Class<? extends Enum<?>> targetEnum)

Utility function to auto generate mapping between two enums that have same values (name) All values in the sourceEnum must have values in targetEnum, otherwise RuntimeException is thrown