ListUtils.java

/*
 * Copyright (c) 2014. by Robusta Code and individual contributors
 *  as indicated by the @authors tag. See the copyright.txt in the
 * distribution for a full listing of individual contributors.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 io.robusta.rra.utils;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

/**
 * Small class for commn tasks on Lists Created by Nicolas Zozol for Robusta
 * Code
 * 
 * @author Nicolas Zozol
 */
public class ListUtils {

    /**
     * The list will be modified if all elements are not unique.
     * <p>
     * For exemple, if list is 3,4,5,3,5,3,0,11, then after setUnicity(list),
     * list will be 3,4,5,0,11<br>
     * The function removes element with highest index in the list
     * </p>
     * 
     * @param list
     *            the list to modify
     */
    public static void setUnicity( List list ) {

        if ( list == null ) {
            return;
        }

        if ( list.size() <= 1 )
            return;

        Object current;

        for ( int i = 0; i < list.size(); i++ ) {
            current = list.get( i );

            int index = list.lastIndexOf( current );
            if ( index != i ) {
                list.remove( index );
                setUnicity( list );
            }
        }

    }

    public static <T> List<T> list( Collection<T> collection ) {
        ArrayList<T> list = new ArrayList<T>();
        for ( T t : collection ) {
            list.add( t );
        }
        return list;
    }

    public static String join( String glue, Collection collection ) {

        StringBuilder result = new StringBuilder();
        Iterator it = collection.iterator();
        while ( it.hasNext() ) {
            Object o = it.next();
            result.append( o.toString() );
            if ( it.hasNext() ) {
                result.append( glue );
            }
        }

        return result.toString();
    }

}