org.josef.util

Class CReflection

java.lang.Object

org.josef.util.CReflection

@Status(stage=PRODUCTION,
        unitTests=COMPLETE)
 @Review(by="Kees Schotanus",at="2009-09-28") @Review(by="Kees Schotanus",at="2010-08-26",reason="Reviewed new functionality to getAllGetters/Setters")
public final class CReflection
extends Object

Utility class to aid in using reflection.

Version:

1.0 $Revision: 6483 $

Author:

Kees Schotanus

Field Summary

Fields

Modifier and Type	Field and Description
static Map<Class<?>,Object>	primitiveClassToDefaultValue Mapping of primitive class types to a default value.

Method Summary

Modifier and Type	Method and Description
static void	clearAllMembers(Object object) Clears all member fields on the supplied object.
static Object	evaluatePropertyExpression(Object bean, String propertyExpression) Gets the value of the supplied propertyExpression from the supplied bean.
static List<Field>	getAllAnnotatedFields(Class<?> classWithAnnotatedFields, Class<? extends Annotation> annotation) Gets all the Fields with an annotation of the supplied annotation type, that are directly or indirectly (at a super class) defined on the supplied classWithAnnotatedFields.
static List<Method>	getAllAnnotatedMethods(Class<?> classWithAnnotatedMethods, Class<? extends Annotation> annotation) Gets all the Methods with an annotation of the supplied annotation type, that are directly or indirectly (at a super class) defined on the supplied classWithAnnotatedMethods.
static List<Field>	getAllFields(Class<?> theClass) Gets all the fields of the supplied class.
static List<Method>	getAllGetters(Class<?> theClass) Gets all the getters declared in the supplied class or one of its super classes, up to, but not including class Object.
static List<Method>	getAllSetters(Class<?> theClass) Gets all the setters declared in the supplied class or one of its super classes, up to, but not including class Object.
static String	getCallingMethod(String methodName) Determines what method called the method with the supplied methodName. jxpfw uses this functionality, allowing you to just code: addPropertyException(Exception) without the need to supply the actual name of the property.
static List<Field>	getDeclaredAnnotatedFields(Class<?> classWithAnnotatedFields, Class<? extends Annotation> annotation) Gets all the Fields with an annotation of the supplied annotation type, that are directly defined on the supplied classWithAnnotatedFields.
static List<Method>	getDeclaredAnnotatedMethods(Class<?> classWithAnnotatedMethods, Class<? extends Annotation> annotation) Gets all the Methods with an annotation of the supplied annotation type, that are directly defined on the supplied classWithAnnotatedMethods.
static List<Method>	getDeclaredGetters(Class<?> theClass) Gets all the getters declared in the supplied class.
static List<Method>	getDeclaredPublicStaticMethods(Class<?> theClass) Gets all the public static methods declared in the supplied class.
static List<Method>	getDeclaredSetters(Class<?> theClass) Gets all the setters declared in the supplied class.
static String	getScalarPropertyName(String propertyName) Gets the scalar (without an index) property name of the supplied propertyName.
static Object	invokeGetMethod(Object object, String propertyName) Invokes the get...() method corresponding to the supplied propertyName.
static Object	invokeGetMethod(Object object, String propertyName, int index) Invokes the get...(index) method corresponding to the supplied propertyName.
static void	invokeSetMethod(Object object, String propertyName, Object propertyValue, Class<?> propertyClass) Invokes the set...(propertyValue) method that corresponds to the supplied property.
static String	methodToProperty(String method) Converts the supplied method name to the corresponding property name.
static Method	propertyToGetMethod(Object object, String property) Gets the method that would get the supplied property.
static String	propertyToGetMethod(String property) Gets the name of the method that would get the supplied property.
static String	propertyToSetMethod(String property) Creates the name of the set...() method from the supplied property name.

Methods inherited from class java.lang.Object

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

Field Detail

primitiveClassToDefaultValue

public static final Map<Class<?>,Object> primitiveClassToDefaultValue

Mapping of primitive class types to a default value. This map is necessary when invoking a method using Method.invoke(Object, Object...) and one of the arguments is of primitive type.

Method Detail

getDeclaredPublicStaticMethods

public static List<Method> getDeclaredPublicStaticMethods(Class<?> theClass)

Gets all the public static methods declared in the supplied class.

Parameters:

theClass - The class to get all the public static methods from.

Returns:

The list of all public static methods of the supplied class.
The returned list is possibly empty, but never null.

getAllGetters

public static List<Method> getAllGetters(Class<?> theClass)

Gets all the getters declared in the supplied class or one of its super classes, up to, but not including class Object.
Note: Only when class Object is supplied as a parameter, all getters of class Object will be returned

Parameters:

theClass - The class to get all the getters from.

Returns:

The list of all getters declared in the supplied class or one of its super classes, up to, but not including class Object.

See Also:

getDeclaredGetters(Class)

getDeclaredGetters

public static List<Method> getDeclaredGetters(Class<?> theClass)

Gets all the getters declared in the supplied class.
A method is a getter when the method:

• has a name starting with either 'get' or 'is'
• is public
• accepts no parameters
• has a non-void return type that is not an array

Parameters:

theClass - The class to get all the getters from.

Returns:

The list of all getters of the supplied class.

getAllSetters

public static List<Method> getAllSetters(Class<?> theClass)

Gets all the setters declared in the supplied class or one of its super classes, up to, but not including class Object.
Note: Only when class Object is supplied as a parameter, all setters of class Object will be returned

Parameters:

theClass - The class to get all the setters from.

Returns:

The list of all setters declared in the supplied class or one of its super classes, up to, but not including class Object.

See Also:

getDeclaredSetters(Class)

getDeclaredSetters

public static List<Method> getDeclaredSetters(Class<?> theClass)

Gets all the setters declared in the supplied class.
A method is a setter when the method:

• has a name starting with 'set'
• is public
• accepts a single parameter that is not an array
• has a void return type

Parameters:

theClass - The class to get all the setters from.

Returns:

The list of all setters of the supplied class.

getAllFields

public static List<Field> getAllFields(Class<?> theClass)

Gets all the fields of the supplied class.
This includes all the fields declared in the super classes of the supplied class, but excludes the synthetic members that may have been added by code coverage tools.

Parameters:

theClass - The class to get the fields from.

Returns:

All the fields declared in the supplied class.
Fields are ordered from the supplied class up to, but not including, fields of class Object.

evaluatePropertyExpression

public static Object evaluatePropertyExpression(Object bean,
                                                String propertyExpression)

Gets the value of the supplied propertyExpression from the supplied bean.
The supplied propertyExpression may be a simple property name like "name" but it may also be a chained property name like: "company.name". In the latter case, it is assumed that a getCompany() method exists on the supplied bean and that it returns an Object that in turn has a getName() method.
Finally, it is possible to use an index like: "name[0]" for example. In this case, "name" should either resolve to an array or list.

Parameters:

bean - The bean to get the property value from.

propertyExpression - The property expression to evaluate.
A property expression looks like this: propertyName([int|"n"])*(.propertyName([int|"n"])*)*

Returns:

The value corresponding to the supplied propertyExpression.

Throws:

IllegalArgumentException - When the supplied propertyExpression is empty or when it can not be evaluated.

NullPointerException - When either the supplied bean or propertyExpression is null.

getScalarPropertyName

public static String getScalarPropertyName(String propertyName)

Gets the scalar (without an index) property name of the supplied propertyName.
For example: getScalarPropertyname("age") and getScalarPropertyname("age[0]") would both return "age".
Note: This method does not test whether the supplied propertyName is a valid Java property name. This method for example happily accepts "age{...}" and return it as-is, since it has no brackets.

Parameters:

propertyName - The property name to get the scalar property name from.

Returns:

The scalar property name.
When the supplied propertyName already represents a scalar, it is returned as is.

Throws:

IllegalArgumentException - When the supplied propertyName is empty or, when there is no matching set of opening and closing brackets.

NullPointerException - When the supplied propertyName is null.

invokeGetMethod

public static Object invokeGetMethod(Object object,
                                     String propertyName)
                              throws ReflectiveOperationException

Invokes the get...() method corresponding to the supplied propertyName.
Note: for boolean properties it is customary to use is...() or has...() instead of get...() so this method will attempt to invoke these methods when the get...() method fails.

Parameters:

object - Object on which the get...() method will be invoked.

propertyName - Name of the property.
This name determines what get...() method should be invoked.

Returns:

The object that is the result of object.getProperty().

Throws:

ReflectiveOperationException - When an error occurs while invoking the method.

NullPointerException - When the supplied object is null or when the supplied propertyName is null.

invokeGetMethod

public static Object invokeGetMethod(Object object,
                                     String propertyName,
                                     int index)
                              throws ReflectiveOperationException

Invokes the get...(index) method corresponding to the supplied propertyName.
Note: for boolean properties it is customary to use is...() or has...() instead of get...() so this method will attempt to invoke these methods when the get...() method fails.

Parameters:

object - Object on which the get...() method will be invoked.

propertyName - Name of the property.
This name determines what get...() method should be invoked.

index - Index of the array element that should be fetched.

Returns:

The object that is the result of object.getProperty(index).

Throws:

ReflectiveOperationException - When an error occurs while invoking the method.

NullPointerException - When the supplied object is null or when the supplied propertyName is null.

invokeSetMethod

public static void invokeSetMethod(Object object,
                                   String propertyName,
                                   Object propertyValue,
                                   Class<?> propertyClass)
                            throws ReflectiveOperationException

Invokes the set...(propertyValue) method that corresponds to the supplied property. set...() on the supplied object.

Parameters:

object - Object on which the set...() method will be invoked.

propertyName - Name of the property.

propertyValue - Value to which the property should be set.

propertyClass - Class of the property.
When this parameter is null the class is taken from the supplied propertyValue. Supply a non null value when the property is of primitive type.

Throws:

ReflectiveOperationException - When an error occurs while invoking the method.

NullPointerException - When the supplied object is null or when the supplied propertyName is null.

methodToProperty

public static String methodToProperty(String method)

Converts the supplied method name to the corresponding property name.
This method assumes that the supplied method consists of a lower case word, followed by the name of the property, where the property name starts with an upper case character.

Parameters:

method - Method name.
Should be the name of a method that is either a getter or a setter.

Returns:

Property name corresponding to the supplied method name.

Throws:

IllegalArgumentException - When the supplied method could not be converted to a property name or when the method is empty.

NullPointerException - When the supplied method is null.

propertyToGetMethod

public static String propertyToGetMethod(String property)

Gets the name of the method that would get the supplied property.
For a property named 'thing' this method would return getThing.

Parameters:

property - The name of the property.

Returns:

The name of the method that would get the supplied property.

Throws:

IllegalArgumentException - When the supplied property is empty.

NullPointerException - When the supplied property is null.

propertyToGetMethod

public static Method propertyToGetMethod(Object object,
                                         String property)
                                  throws NoSuchMethodException

Gets the method that would get the supplied property.
For a property named 'thing' for example, the getter is normally named getThing(). When this method exists, it is returned. Additionally the methods called isThing() and hasThing() are checked for existence.

Parameters:

object - The object that contains the supplied property.

property - Name of the property.

Returns:

The method that corresponds to the getter of the supplied property.

Throws:

NoSuchMethodException - When no getters method exists that corresponds to the supplied property.

NullPointerException - When either the supplied object or property is null.

IllegalArgumentException - When the supplied property is empty.

propertyToSetMethod

public static String propertyToSetMethod(String property)

Creates the name of the set...() method from the supplied property name.
Technically this method converts the first character of the property name to upper case and prepends "set" to the result.

Parameters:

property - Name of the property.

Returns:

Name of the set method corresponding to the supplied parameter.

Throws:

IllegalArgumentException - When the supplied property is empty.

NullPointerException - When the supplied property is null.

clearAllMembers

public static void clearAllMembers(Object object)

Clears all member fields on the supplied object.
Effectively this method calls all setters with the appropriate default value corresponding to the type of the parameter. Primitive booleans are initialized to false, remaining primitives to 0 and references to null.
Fields that could not be cleared, appear in the log as warnings.

Parameters:

object - The object for which all fields must be cleared.

Throws:

NullPointerException - When the supplied object is null.

getCallingMethod

public static String getCallingMethod(String methodName)

Determines what method called the method with the supplied methodName.
jxpfw uses this functionality, allowing you to just code: addPropertyException(Exception) without the need to supply the actual name of the property. The addPropertyException(...) figures out which method was the caller and deduces the name of the property from the returned method name. Be careful with using constructors and initializers. They are coded as <init> and <clinit>. Executing the following code:

CReflection.getCallingMethod("org.josef.util.CReflectionTest.<init>

results in: "newInstance", for example.
Note: Do not use this method in combination with Aspect/J or comparable tools as this method will fail and return an Aspect/J method instead of the method you want. Please let me know if you need this functionality. I can probably add a simple check on Aspect/J being used.

Parameters:

methodName - Name of the method for which the caller must be returned.
To be absolutely sure you that you get the correct result, you may want to fully qualify the name of the method, e.g.: josef.util.CFile.readTextFile.
Note: don't add parenthesis to the case sensitive name.

Returns:

Simple, unqualified name of the method that called the method with the supplied methodName or null when no caller could be located.

getDeclaredAnnotatedFields

public static List<Field> getDeclaredAnnotatedFields(Class<?> classWithAnnotatedFields,
                                                     Class<? extends Annotation> annotation)

Gets all the Fields with an annotation of the supplied annotation type, that are directly defined on the supplied classWithAnnotatedFields.

Parameters:

classWithAnnotatedFields - The class to check for Fields with annotations of type annotation.

annotation - The type of annotation the Field should have in order to be returned.

Returns:

All Fields in the supplied classWithAnnotatedFields that have an annotation of the supplied annotation type.
The returned List may be empty but will never be null.

Throws:

NullPointerException - When either the supplied classWithAnnotatedFields or annotation is null.

getAllAnnotatedFields

public static List<Field> getAllAnnotatedFields(Class<?> classWithAnnotatedFields,
                                                Class<? extends Annotation> annotation)

Gets all the Fields with an annotation of the supplied annotation type, that are directly or indirectly (at a super class) defined on the supplied classWithAnnotatedFields.

Parameters:

classWithAnnotatedFields - The class to check for Fields with annotations of type annotation.

annotation - The type of annotation the Field should have in order to be returned.

Returns:

All Fields in the supplied classWithAnnotatedFields that have an annotation of the supplied annotation type.
The returned List may be empty but will never be null.

Throws:

NullPointerException - When either the supplied classWithAnnotatedFields or annotation is null.

getDeclaredAnnotatedMethods

public static List<Method> getDeclaredAnnotatedMethods(Class<?> classWithAnnotatedMethods,
                                                       Class<? extends Annotation> annotation)

Gets all the Methods with an annotation of the supplied annotation type, that are directly defined on the supplied classWithAnnotatedMethods.

Parameters:

classWithAnnotatedMethods - The class to check for Methods with annotations of type annotation.

annotation - The type of annotation the Method should have in order to be returned.

Returns:

All Methods in the supplied classWithAnnotatedMethods that have an annotation of the supplied annotation type.
The returned List may be empty but will never be null.

Throws:

NullPointerException - When either the supplied classWithAnnotatedMethods or annotation is null.

getAllAnnotatedMethods

public static List<Method> getAllAnnotatedMethods(Class<?> classWithAnnotatedMethods,
                                                  Class<? extends Annotation> annotation)

Gets all the Methods with an annotation of the supplied annotation type, that are directly or indirectly (at a super class) defined on the supplied classWithAnnotatedMethods.

Parameters:

classWithAnnotatedMethods - The class to check for Methods with annotations of type annotation.

annotation - The type of annotation the Method should have in order to be returned.

Returns:

All Methods in the supplied classWithAnnotatedMethods that have an annotation of the supplied annotation type.
The returned List may be empty but will never be null.

Throws:

NullPointerException - When either the supplied classWithAnnotatedMethods or annotation is null.