Java Constructor.getDeclaredAnnotations方法代码示例

import java.lang.reflect.Constructor; //导入方法依赖的package包/类
public void testConstructor2()
{
	try
	{
		Constructor<TestClass1> ctor = TestClass1.class.getConstructor
			(new Class[] {Integer.class});
					
		// No annotations should be present on the constructor itself
		Annotation[] ctor_annotations = ctor.getDeclaredAnnotations();
		assertTrue( ctor_annotations.length == 0);			
		ctor_annotations = ctor.getAnnotations();
		assertTrue( ctor_annotations.length == 0);			

		// 3 parameter annotation should be present on the constructor
		Annotation[][] params = ctor.getParameterAnnotations();
		assertTrue(params.length != 0);  // there are parameters
		// first parameter has 3 annotations
		assertTrue(params[0].length  == 3);
	}
	catch (NoSuchMethodException e)
	{
		fail("Failed to get TestClass1 constructor (Integer)");
	}
}
 

import java.lang.reflect.Constructor; //导入方法依赖的package包/类
public void testConstructor3()
{
	try
	{
		Constructor<TestClass1> ctor = TestClass1.class.getConstructor();
					
		// No annotations should be present on the constructor itself
		Annotation[] ctor_annotations = ctor.getDeclaredAnnotations();
		assertTrue( ctor_annotations.length == 0);			
		ctor_annotations = ctor.getAnnotations();
		assertTrue( ctor_annotations.length == 0);			

		// No parameters (and therefore no parameter annotations) should be
		// present on the constructor
		Annotation[][] params = ctor.getParameterAnnotations();
		assertTrue(params.length == 0); // no parameters

	}
	catch (NoSuchMethodException e)
	{
		fail("Failed to get TestClass1 constructor()");
	}
}
 

import java.lang.reflect.Constructor; //导入方法依赖的package包/类
public void addConstructor(Constructor<?> constructor) throws Exception {
    List<Type> paramTypes = new ArrayList<Type>();
    for (Class<?> paramType : constructor.getParameterTypes()) {
        paramTypes.add(Type.getType(paramType));
    }
    String methodDescriptor = Type.getMethodDescriptor(VOID_TYPE, paramTypes.toArray(EMPTY_TYPES));

    MethodVisitor methodVisitor = visitor.visitMethod(Opcodes.ACC_PUBLIC, "<init>", methodDescriptor, signature(constructor), EMPTY_STRINGS);

    for (Annotation annotation : constructor.getDeclaredAnnotations()) {
        if (annotation.annotationType().getAnnotation(Inherited.class) != null) {
            continue;
        }
        Retention retention = annotation.annotationType().getAnnotation(Retention.class);
        AnnotationVisitor annotationVisitor = methodVisitor.visitAnnotation(Type.getType(annotation.annotationType()).getDescriptor(), retention != null && retention.value() == RetentionPolicy.RUNTIME);
        annotationVisitor.visitEnd();
    }

    methodVisitor.visitCode();

    // this.super(p0 .. pn)
    methodVisitor.visitVarInsn(Opcodes.ALOAD, 0);
    for (int i = 0; i < constructor.getParameterTypes().length; i++) {
        methodVisitor.visitVarInsn(Type.getType(constructor.getParameterTypes()[i]).getOpcode(Opcodes.ILOAD), i + 1);
    }
    methodVisitor.visitMethodInsn(Opcodes.INVOKESPECIAL, superclassType.getInternalName(), "<init>", methodDescriptor, false);

    methodVisitor.visitInsn(Opcodes.RETURN);
    methodVisitor.visitMaxs(0, 0);
    methodVisitor.visitEnd();
}
 

import java.lang.reflect.Constructor; //导入方法依赖的package包/类
public void testConstructor1()
{
	try
	{
		Constructor<TestClass1> ctor = TestClass1.class.getConstructor
			(new Class[] {Integer.class, String.class});
				
		Annotation[] ctor_annotations = ctor.getDeclaredAnnotations();
		assertTrue( ctor_annotations.length == 2);

		boolean[] annot_count = new boolean[] {false, false};
		for (int i=0; i<2; i++) 
		{
			assertTrue( ctor_annotations[i].annotationType().equals(A0.class)
					|| ctor_annotations[i].annotationType().equals(A5.class));
			
			if (ctor_annotations[i] instanceof A0)
			{
				annot_count[0] = true;
			}
			else if (ctor_annotations[i] instanceof A5)
			{
				annot_count[1] = true;			
			}								
		}
		
		A0 a0 = (A0) ctor.getAnnotation(A0.class);
		assertTrue (ctor.getAnnotation(A0.class).equals(a0));
		A5 a5 = (A5) ctor.getAnnotation(A5.class);
		assertTrue (ctor.getAnnotation(A5.class).equals(a5));
		
		// Make sure both @A0 and @A5 were found
		assertTrue (annot_count[0] && annot_count[1]);
				
		// Verify the annotations associated with the constructor parameters			
		Annotation[][] params = ctor.getParameterAnnotations();
		assertTrue(params.length != 0);	
		// first parameter has 1 annotation
		assertTrue(params[0].length  == 1);
		// second parameter has 4annotations			
		assertTrue(params[1].length  == 4);
		assertTrue(params[0][0] instanceof A0);
		
		annot_count = new boolean[] {false, false, false, false};
		for (int i=0; i<4; i++)
		{		
			if (params[1][i] instanceof A0)
			{
				annot_count[0] = true;
			}
			else if (params[1][i] instanceof A1)
			{
				annot_count[1] = true;
			}
			else if (params[1][i] instanceof A2)
			{
				annot_count[2] = true;
			}
			else if (params[1][i] instanceof A3)
			{
				annot_count[3] = true;
			}
		}				
		assertTrue (annot_count[0] && annot_count[1] &&
				annot_count[2] && annot_count[3]);		                                                            
	}
	catch (NoSuchMethodException e)
	{
		fail("Failed to get TestClass1 constructor (Integer, String): " + e.getMessage());
	}		
}