Parameter.java

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2011, Red Hat, Inc. and/or its affiliates, and individual
 * contributors by the @authors tag. See the copyright.txt in the
 * distribution for a full listing of individual contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jboss.solder.reflection.annotated;

import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

import org.jboss.solder.reflection.Reflections;


/**
 * An implementation of Member for parameters
 *
 * @author pmuir
 */
abstract class Parameter<X> implements AnnotatedElement {

    static <X> Parameter<X> create(Member declaringMember, int position) {
        if (declaringMember instanceof Method) {
            return new MethodParameter<X>((Method) declaringMember, position);
        } else if (declaringMember instanceof Constructor<?>) {
            return new ConstructorParameter<X>(Reflections.<Constructor<X>>cast(declaringMember), position);
        } else {
            throw new IllegalArgumentException("Can only process members of type Method and Constructor, cannot process " + declaringMember);
        }
    }

    private static class MethodParameter<X> extends Parameter<X> {

        private final Method declaringMethod;

        private MethodParameter(Method declaringMethod, int position) {
            super(position);
            this.declaringMethod = declaringMethod;
        }

        @Override
        public Method getDeclaringMember() {
            return declaringMethod;
        }

        public Annotation[] getAnnotations() {
            if (declaringMethod.getParameterAnnotations().length > getPosition()) {
                return declaringMethod.getParameterAnnotations()[getPosition()];
            } else {
                return Reflections.EMPTY_ANNOTATION_ARRAY;
            }
        }

        @Override
        public Type getBaseType() {
            if (declaringMethod.getGenericParameterTypes().length > getPosition()) {
                return declaringMethod.getGenericParameterTypes()[getPosition()];
            } else {
                return declaringMethod.getParameterTypes()[getPosition()];
            }
        }

    }

    private static class ConstructorParameter<X> extends Parameter<X> {

        private final Constructor<X> declaringConstructor;

        private ConstructorParameter(Constructor<X> declaringConstructor, int position) {
            super(position);
            this.declaringConstructor = declaringConstructor;
        }

        @Override
        public Constructor<X> getDeclaringMember() {
            return declaringConstructor;
        }

        public Annotation[] getAnnotations() {
            if (declaringConstructor.getParameterAnnotations().length > getPosition()) {
                return declaringConstructor.getParameterAnnotations()[getPosition()];
            } else {
                return Reflections.EMPTY_ANNOTATION_ARRAY;
            }
        }

        @Override
        public Type getBaseType() {
            if (declaringConstructor.getGenericParameterTypes().length > getPosition()) {
                return declaringConstructor.getGenericParameterTypes()[getPosition()];
            } else {
                return declaringConstructor.getParameterTypes()[getPosition()];
            }
        }

    }

    private final int position;

    Parameter(int position) {
        this.position = position;
    }

    public abstract Member getDeclaringMember();

    public int getPosition() {
        return position;
    }

    @Override
    public int hashCode() {
        int hash = 1;
        hash = hash * 31 + getDeclaringMember().hashCode();
        hash = hash * 31 + Integer.valueOf(position).hashCode();
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Parameter<?>) {
            Parameter<?> that = (Parameter<?>) obj;
            return this.getDeclaringMember().equals(that.getDeclaringMember()) && this.getPosition() == that.getPosition();
        } else {
            return false;
        }

    }


    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
        for (Annotation annotation : getAnnotations()) {
            if (annotation.annotationType().equals(annotationClass)) {
                return annotationClass.cast(annotation);
            }
        }
        return null;
    }

    public Annotation[] getDeclaredAnnotations() {
        return getAnnotations();
    }

    public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
        return getAnnotation(annotationClass) != null;
    }

    public abstract Type getBaseType();

}