jodd.util

Class AnnotationDataReader<A extends java.lang.annotation.Annotation,D extends AnnotationDataReader.AnnotationData<A>>

java.lang.Object

jodd.util.AnnotationDataReader<A,D>

public abstract class AnnotationDataReader<A extends java.lang.annotation.Annotation,D extends AnnotationDataReader.AnnotationData<A>>
extends java.lang.Object

Annotation reader reads an annotation and returns annotation data object populated with annotation element values. Can be used to simulate annotation inheritance, as such does not exist in Java.

There are 3 ways how this class can be used. First, it can be used on single annotation, but that does not make much sense.

Second way is with child and parent annotation. The parent annotation is default one, like a base class. Child annotation contains some predefined values different from parent. Note that child annotation does NOT have to specify all elements - all missing elements will be read from default parent annotation. So child annotation behaves like it is overriding the parent one.

Third way is similar, except the child annotation is also annotated with parent annotation! Besides overriding features and default values, this way we can finalize some element value and prevent it from being modified by user.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AnnotationDataReader.AnnotationData<N extends java.lang.annotation.Annotation> Base class for annotation data, for holding annotation elements values.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.Class<A>	annotationClass
protected java.lang.annotation.Annotation	defaultAnnotation

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AnnotationDataReader(java.lang.Class<A> annotationClass, java.lang.Class<? extends java.lang.annotation.Annotation> defaultAnnotationClass) Creates new annotation data reader using annotation definition from class generics.

Method Summary

Modifier and Type	Method and Description
protected abstract D	createAnnotationData(A annotation) Creates annotation data from given annotation.
java.lang.Class<A>	getAnnotationClass() Returns annotation class.
boolean	hasAnnotation(java.lang.reflect.AccessibleObject accessibleObject) Returns true if annotation is present on given accessible object.
D	readAnnotationData(java.lang.reflect.AccessibleObject accessibleObject) Reads annotation data on provided accessible object.
D	readAnnotationData(java.lang.Class<?> type) Reads annotation data on provided type.
protected boolean	readBoolean(A annotation, java.lang.String name, boolean defaultValue) Reads boolean element from the annotation.
protected java.lang.Object	readElement(A annotation, java.lang.String name) Reads annotation element as an object.
protected int	readInt(A annotation, java.lang.String name, int defaultValue) Reads int element from the annotation.
protected java.lang.String	readString(A annotation, java.lang.String name, java.lang.String defaultValue) Reads string element from the annotation.
protected java.lang.String	readStringElement(A annotation, java.lang.String name) Reads non-empty, trimmed, annotation element value.

Methods inherited from class java.lang.Object

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

Field Detail

defaultAnnotation

protected final java.lang.annotation.Annotation defaultAnnotation

annotationClass

protected final java.lang.Class<A extends java.lang.annotation.Annotation> annotationClass

Constructor Detail

AnnotationDataReader

protected AnnotationDataReader(java.lang.Class<A> annotationClass,
                               java.lang.Class<? extends java.lang.annotation.Annotation> defaultAnnotationClass)

Creates new annotation data reader using annotation definition from class generics. Moreover, allows annotation to be annotated with default annotation, for convenient and fail-back value reading.

Parameters:

annotationClass - annotation type to read from

defaultAnnotationClass - optional default annotation type, used to annotate the annotation class.

Method Detail

getAnnotationClass

public java.lang.Class<A> getAnnotationClass()

Returns annotation class.

hasAnnotation

public boolean hasAnnotation(java.lang.reflect.AccessibleObject accessibleObject)

Returns true if annotation is present on given accessible object.

readAnnotationData

public D readAnnotationData(java.lang.reflect.AccessibleObject accessibleObject)

Reads annotation data on provided accessible object. If annotation is not presented, null is returned.

readAnnotationData

public D readAnnotationData(java.lang.Class<?> type)

Reads annotation data on provided type. If annotation is not presented, null is returned.

createAnnotationData

protected abstract D createAnnotationData(A annotation)

Creates annotation data from given annotation.

readStringElement

protected java.lang.String readStringElement(A annotation,
                                             java.lang.String name)

Reads non-empty, trimmed, annotation element value. If annotation value is missing, it will read value from default annotation. If still missing, returns null.

readElement

protected java.lang.Object readElement(A annotation,
                                       java.lang.String name)

Reads annotation element as an object. If annotation value is missing, it will be read from default annotation. If still missing, returns null.

readString

protected java.lang.String readString(A annotation,
                                      java.lang.String name,
                                      java.lang.String defaultValue)

Reads string element from the annotation. Empty strings are detected and default value is returned instead.

readBoolean

protected boolean readBoolean(A annotation,
                              java.lang.String name,
                              boolean defaultValue)

Reads boolean element from the annotation.

readInt

protected int readInt(A annotation,
                      java.lang.String name,
                      int defaultValue)

Reads int element from the annotation.