ClassQualifier

ClassQualifier.java

import javax.inject.Qualifier;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Target({FIELD, PARAMETER, METHOD})
@Retention(RUNTIME)
@Qualifier
public @interface ClassQualifier
{
    Class<?> value();
}

ClassQualifierImpl.java

import java.lang.annotation.Annotation;

import static java.util.Objects.requireNonNull;

@SuppressWarnings("ClassExplicitlyAnnotation")
public class ClassQualifierImpl
        implements ClassQualifier
{
    private final Class<?> value;

    public static ClassQualifier classQualifier(Class<?> value)
    {
        return new ClassQualifierImpl(value);
    }

    private ClassQualifierImpl(Class<?> value)
    {
        this.value = requireNonNull(value, "value is null");
    }

    @Override
    public Class<?> value()
    {
        return value;
    }

    @Override
    public Class<? extends Annotation> annotationType()
    {
        return ClassQualifier.class;
    }

    @Override
    public int hashCode()
    {
        // this is specified in java.lang.annotation.Annotation
        return (127 * "value".hashCode()) ^ value.hashCode();
    }

    @Override
    public boolean equals(Object o)
    {
        if (!(o instanceof ClassQualifier)) {
            return false;
        }
        return value.equals(((ClassQualifier) o).value());
    }

    @Override
    public String toString()
    {
        return "@" + ClassQualifier.class.getName() + "(value=" + value.getName() + ")";
    }
}