IterableInputHelper.java

/*
 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * 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.
 *
 * Contributors:
 *     bstefanescu
 */
package org.nuxeo.ecm.automation.core.impl;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

import org.nuxeo.ecm.automation.OutputCollector;

/**
 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
 */
public class IterableInputHelper {

    // protected static ConcurrentMap<String,String> cache;

    private IterableInputHelper() {
    }

    public static Class<?> getIterableType(Class<?> cl) {
        // TODO first look into a cache
        // Class<?> cl = cache.get(cl.getName());
        return findIterableType(cl);
    }

    @SuppressWarnings("rawtypes")
    public static Type[] findCollectorTypes(Class<? extends OutputCollector> cl) {
        for (Type itf : cl.getGenericInterfaces()) {
            if (itf instanceof ParameterizedType) {
                ParameterizedType ptype = (ParameterizedType) itf;
                if (ptype.getRawType() == OutputCollector.class) {
                    return ptype.getActualTypeArguments();
                }
            }
        }
        throw new IllegalArgumentException("Invalid output collector class: " + cl
                + ". The class must explicitely impelement the OutputCollector interface.");
    }

    public static Class<?> findIterableType(Class<?> cl) {
        if (!Iterable.class.isAssignableFrom(cl)) {
            return null;
        }
        // try generic super class
        Type superType = cl.getGenericSuperclass();
        if (superType instanceof ParameterizedType) {
            ParameterizedType ptype = (ParameterizedType) superType;
            return (Class<?>) ptype.getActualTypeArguments()[0];
        }
        // try generic interfaces
        for (Type itf : cl.getGenericInterfaces()) {
            if (itf instanceof ParameterizedType) {
                ParameterizedType ptype = (ParameterizedType) itf;
                if (ptype.getRawType() == Iterable.class || ptype.getRawType() == Collection.class
                        || ptype.getRawType() == List.class) {
                    return (Class<?>) ptype.getActualTypeArguments()[0];
                }
            }
        }
        // if not descend into the super type and continue.
        if (superType != null) {
            Class<?> superClass = cl.getSuperclass();
            if (superClass != null) {
                return getIterableType(superClass);
            }
        }
        return null;
    }

    static class MyIt implements Iterable<String> {
        @Override
        public Iterator<String> iterator() {
            return null;
        }
    }

    static class MyList implements List<String> {

        @Override
        public int size() {
            return 0;
        }

        @Override
        public boolean isEmpty() {
            return false;
        }

        @Override
        public boolean contains(Object o) {
            return false;
        }

        @Override
        public Iterator<String> iterator() {
            return null;
        }

        @Override
        public Object[] toArray() {
            return null;
        }

        @Override
        public <T> T[] toArray(T[] a) {
            return null;
        }

        @Override
        public boolean add(String e) {
            return false;
        }

        @Override
        public boolean remove(Object o) {
            return false;
        }

        @Override
        public boolean containsAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean addAll(Collection<? extends String> c) {
            return false;
        }

        @Override
        public boolean addAll(int index, Collection<? extends String> c) {
            return false;
        }

        @Override
        public boolean removeAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean retainAll(Collection<?> c) {
            return false;
        }

        @Override
        public void clear() {
        }

        @Override
        public String get(int index) {
            return null;
        }

        @Override
        public String set(int index, String element) {
            return null;
        }

        @Override
        public void add(int index, String element) {
        }

        @Override
        public String remove(int index) {
            return null;
        }

        @Override
        public int indexOf(Object o) {
            return 0;
        }

        @Override
        public int lastIndexOf(Object o) {
            return 0;
        }

        @Override
        public ListIterator<String> listIterator() {
            return null;
        }

        @Override
        public ListIterator<String> listIterator(int index) {
            return null;
        }

        @Override
        public List<String> subList(int fromIndex, int toIndex) {
            return null;
        }

    }

    static class MyCol implements Collection<String> {

        @Override
        public int size() {
            return 0;
        }

        @Override
        public boolean isEmpty() {
            return false;
        }

        @Override
        public boolean contains(Object o) {
            return false;
        }

        @Override
        public Iterator<String> iterator() {
            return null;
        }

        @Override
        public Object[] toArray() {
            return null;
        }

        @Override
        public <T> T[] toArray(T[] a) {
            return null;
        }

        @Override
        public boolean add(String e) {
            return false;
        }

        @Override
        public boolean remove(Object o) {
            return false;
        }

        @Override
        public boolean containsAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean addAll(Collection<? extends String> c) {
            return false;
        }

        @Override
        public boolean removeAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean retainAll(Collection<?> c) {
            return false;
        }

        @Override
        public void clear() {
        }
    }

}