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/**
 * Copyright (c) 2014-2015, biezhi 王爵 ([email protected])
 *
 * 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.unique.commons.utils;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;

/**
 * collection util
 * @author biezhi
 * @since 1.0
 */
public class CollectionUtil {

    /**
     * new HashMap
     */
    public static  HashMap newHashMap() {
        return new HashMap();
    }

    /**
     * new HashMap and initialCapacity
     */
    public static  HashMap newHashMap(int size) {
        return new HashMap();
    }
    
    /**
     * new concurrentHashMap
     */
    public static  ConcurrentHashMap newConcurrentHashMap() {
        return new ConcurrentHashMap();
    }
    
    /**
     * new concurrentHashMap and initialCapacity
     */
    public static  ConcurrentHashMap newConcurrentHashMap(int size) {
        return new ConcurrentHashMap(size);
    }

    /**
     * new ArrayList
     */
    public static  ArrayList newArrayList() {
        return new ArrayList();
    }
    
    /**
     * new ArrayList and initialCapacity
     */
    public static  ArrayList newArrayList(int size) {
        return new ArrayList(size);
    }

    /**
     * new HashSet
     */
    public static  HashSet newHashSet() {
        return new HashSet();
    }

    /**
     * new HashSet and initialCapacity
     */
    public static  HashSet newHashSet(int size) {
        return new HashSet(size);
    }
    
    /**
     * new TreeSet
     */
    public static  TreeSet newTreeSet() {
        return new TreeSet();
    }
    
    /**
     * map sort
     */
    public static  Map sortMap(Map map, Comparator> compator) {
        Map result = new LinkedHashMap();
        List> entries = new ArrayList>(map.entrySet());
        Collections.sort(entries, compator);
        for (Entry entry : entries) {
            result.put(entry.getKey(), entry.getValue());
        }
        return result;
    }
    
    /**
     * return collection is empty
     */
    public static  boolean isEmpty(Collection c){
        return (null == c || c.isEmpty());
    }
    
    /**
     * return map is empty
     */
    public static  boolean isEmpty(Map map){
        return (null == map || map.isEmpty());
    }
    
    /**
     * return array is empty
     */
    public static  boolean isEmpty(T[] arr){
    	return null == arr || arr.length == 0;
    }
}