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package com.sun.jersey.core.reflection;

import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.security.AccessController;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import javax.ws.rs.Consumes;
import javax.ws.rs.CookieParam;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.Encoded;
import javax.ws.rs.FormParam;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.HttpMethod;
import javax.ws.rs.MatrixParam;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;

/**
 *
 * @author Paul.Sandoz@Sun.Com
 */
public final class AnnotatedMethod implements AnnotatedElement {
    @SuppressWarnings("unchecked")
    private static final Set<Class<? extends Annotation>>
            METHOD_META_ANNOTATIONS = getSet(
                HttpMethod.class);

    @SuppressWarnings("unchecked")
    private static final Set<Class<? extends Annotation>>
            METHOD_ANNOTATIONS = getSet(
                Path.class,
                Produces.class,
                Consumes.class);

    @SuppressWarnings("unchecked")
    private static final Set<Class<? extends Annotation>>
            PARAMETER_ANNOTATIONS = getSet(
        Context.class,
        Encoded.class,
        DefaultValue.class,
        MatrixParam.class,
        QueryParam.class,
        CookieParam.class,
        HeaderParam.class,
        PathParam.class,
        FormParam.class);

    private static Set<Class<? extends Annotation>> getSet(Class<? extends Annotation>... cs) {
        Set<Class<? extends Annotation>> s = new HashSet<Class<? extends Annotation>>();
        for (Class<? extends Annotation> c : cs) s.add(c);
        return s;
    }

    private final Method m;

    private final Method am;

    private final Annotation[] methodAnnotations;

    private final Annotation[][] parameterAnnotations;

    public AnnotatedMethod(Method m) {
        this.m = m;
        this.am = findAnnotatedMethod(m);

        if (m.equals(am)) {
            methodAnnotations = m.getAnnotations();
            parameterAnnotations = m.getParameterAnnotations();
        } else {
            methodAnnotations = mergeMethodAnnotations(m, am);
            parameterAnnotations = mergeParameterAnnotations(m, am);
        }
    }

    public Method getMethod() {
        return am;
    }

    public Annotation[][] getParameterAnnotations() {
        return parameterAnnotations.clone();
    }

    public Class<?>[] getParameterTypes() {
        return am.getParameterTypes();
    }

    public TypeVariable<Method>[] getTypeParameters() {
        return am.getTypeParameters();
    }

    public Type[] getGenericParameterTypes() {
        return am.getGenericParameterTypes();
    }

    public <T extends Annotation> List<T> getMetaMethodAnnotations(
            Class<T> annotation) {
        List <T> ma = new ArrayList<T>();
        for (Annotation a : methodAnnotations) {
            if (a.annotationType().getAnnotation(annotation) != null) {
                ma.add(a.annotationType().getAnnotation(annotation));
            }
        }

        return ma;
    }

    @Override
    public String toString() {
        return m.toString();
    }

    // AnnotatedElement

    public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) {
        for (Annotation ma : methodAnnotations) {
            if (ma.annotationType() == annotationType)
                return true;
        }
        return false;
    }

    public <T extends Annotation> T getAnnotation(Class<T> annotationType) {
        for (Annotation ma : methodAnnotations) {
            if (ma.annotationType() == annotationType)
                return annotationType.cast(ma);
        }
        return am.getAnnotation(annotationType);
    }

    public Annotation[] getAnnotations() {
        return methodAnnotations.clone();
    }

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


    //

    private static Annotation[] mergeMethodAnnotations(Method m, Method am) {
        List<Annotation> al = asList(m.getAnnotations());
        for (Annotation a : am.getAnnotations()) {
            if (!m.isAnnotationPresent(a.getClass()))
                al.add(a);
        }

        return al.toArray(new Annotation[0]);
    }

    private static Annotation[][] mergeParameterAnnotations(Method m, Method am) {
        Annotation[][] mp = m.getParameterAnnotations();
        Annotation[][] amp = am.getParameterAnnotations();

        List<List<Annotation>> ala = new ArrayList<List<Annotation>>();
        for (int i = 0; i < mp.length; i++) {
            List<Annotation> al = asList(mp[i]);
            for (Annotation a : amp[i])
                if (!isAnnotatonPresent(a.getClass(), al))
                    al.add(a);
            ala.add(al);
        }

        Annotation[][] paa = new Annotation[mp.length][];
        for (int i = 0; i < mp.length; i++) {
            paa[i] = ala.get(i).toArray(new Annotation[0]);
        }

        return paa;
    }

    private static boolean isAnnotatonPresent(Class<? extends Annotation> ca, List<Annotation> la) {
        for (Annotation a : la) {
            if (ca == a.getClass())
                return true;
        }
        return false;
    }

    private static Method findAnnotatedMethod(Method m) {
        Method am = findAnnotatedMethod(m.getDeclaringClass(), m);
        return (am != null) ? am : m;
    }

    private static Method findAnnotatedMethod(Class<?> c, Method m) {
        if (c == Object.class)
            return null;

        m = AccessController.doPrivileged(ReflectionHelper.findMethodOnClassPA(c, m));
        if (m == null)
            return null;

        if (hasAnnotations(m)) return m;

        // Super classes take precendence over interfaces
        Class<?> sc = c.getSuperclass();
        if (sc != null && sc != Object.class) {
            Method sm = findAnnotatedMethod(sc, m);
            if (sm != null) return sm;
        }

        for (Class<?> ic : c.getInterfaces()) {
            Method im = findAnnotatedMethod(ic, m);
            if (im != null) return im;
        }

        return null;
    }

    private static boolean hasAnnotations(Method m) {
        return hasMetaMethodAnnotations(m) ||
                hasMethodAnnotations(m) ||
                hasParameterAnnotations(m);
    }

    private static boolean hasMetaMethodAnnotations(Method m) {
        for (Class<? extends Annotation> ac : METHOD_META_ANNOTATIONS)
            for (Annotation a : m.getAnnotations())
                if (a.annotationType().getAnnotation(ac) != null) return true;

        return false;
    }

    private static boolean hasMethodAnnotations(Method m) {
        for (Class<? extends Annotation> ac : METHOD_ANNOTATIONS)
            if (m.isAnnotationPresent(ac)) return true;

        return false;
    }

    private static boolean hasParameterAnnotations(Method m) {
        for (Annotation[] as : m.getParameterAnnotations())
            for (Annotation a : as)
                if (PARAMETER_ANNOTATIONS.contains(a.annotationType())) return true;

        return false;
    }

    private static <T> List<T> asList(T... ts) {
        List<T> l = new ArrayList<T>();
        for (T t : ts) l.add(t);
        return l;
    }
}