CollectionsX.java

/*
 * Copyright (c) 2010, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * 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.wso2.carbon.humantask.core.utils;

import java.util.Collection;
import java.util.Iterator;

public final class CollectionsX {
    private CollectionsX() {
    }

//    public static <T> Collection<T> insert(Collection<T> coll, Enumeration<? extends T> e) {
//        while (e.hasMoreElements()) {
//            coll.add(e.nextElement());
//        }
//        return coll;
//    }

//    public static <T> Collection<T> insert(Collection<T> coll, Iterator<? extends T> i) {
//        while (i.hasNext()) {
//            coll.add(i.next());
//        }
//        return coll;
//    }

//    public static <T> Collection<T> insert(Collection<T> coll, Collection<? extends T> src) {
//        return insert(coll, src.iterator());
//    }


//    public static <C extends Collection<T>, S, T extends S> C filter(C dest, Collection<S> src, Class<T> t) {
//        return filter(dest, src.iterator(), t);
//    }

//    public static <C extends Collection<T>, S, T extends S> C filter(C newList, Iterator<S> iterator, Class<T> t) {
//        while (iterator.hasNext()) {
//            S next = iterator.next();
//            if (t.isAssignableFrom(next.getClass())) {
//                newList.add((T) next);
//            }
//        }
//        return newList;
//    }

//    /**
//     * Filter a collection by member class.
//     *
//     * @param src    source collection
//     * @param aClass requested class
//     * @return collection consisting of the members of the input that are
//     *         assignable to the given class
//     */
//    @SuppressWarnings("unchecked")
//    public static <T> Collection<T> filter(Collection src, final Class<T> aClass) {
//        return filter(new ArrayList<T>(src.size()), src.iterator(), aClass);
//    }

    /**
     * Remove elements from collection based on the results of specified unary
     * function. An element will be deleted if <code>f.isMember(element)
     * </code>
     * returns <code>true</code>. So: <em>coll' = { x : x el-of coll
     * AND f(x) == false }</em>
     *
     * @param coll
     *            the collection from which to remove elements
     * @param f
     *            the function to apply
     *
     * @return coll, for convenience
     */
    public static <T> Collection<T> removeIf(Collection<T> coll, MemberOfFunction<T> f) {
        Iterator<T> i = coll.iterator();

        while (i.hasNext()) {
            if (f.isMember(i.next())) {
                i.remove();
            }
        }

        return coll;
    }

}