com.yunmel.syncretic.utils.commons.CollectionsUtils.java Source code

Introduction

Here is the source code for com.yunmel.syncretic.utils.commons.CollectionsUtils.java

Source

/*
 * Copyright (c) 2016 yunmle.com(?).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 */
package com.yunmel.syncretic.utils.commons;

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

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang3.StringUtils;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.yunmel.syncretic.bean.BaseEntity;
import com.yunmel.syncretic.utils.jse.Reflections;

/**
 * 
 * @description ?
 *   - ?jeesite.
 * @author xuyq - chainisit@126.com
 * @since 1.0 - 2016715
 */
@SuppressWarnings("rawtypes")
public class CollectionsUtils {

    /**
     * ????(Getter), ??Map.
     * 
     * @param collection ???.
     * @param keyPropertyName ????MapKey??.
     * @param valuePropertyName ????MapValue??.
     */
    @SuppressWarnings("unchecked")
    public static Map extractToMap(final Collection collection, final String keyPropertyName,
            final String valuePropertyName) {
        Map map = Maps.newHashMapWithExpectedSize(collection.size());

        try {
            for (Object obj : collection) {
                map.put(PropertyUtils.getProperty(obj, keyPropertyName),
                        PropertyUtils.getProperty(obj, valuePropertyName));
            }
        } catch (Exception e) {
            throw Reflections.convertReflectionExceptionToUnchecked(e);
        }

        return map;
    }

    /**
     * ????(Getter), ??List.
     * 
     * @param collection ???.
     * @param propertyName ??????.
     */
    @SuppressWarnings("unchecked")
    public static List extractToList(final Collection collection, final String propertyName) {
        List list = Lists.newArrayList(collection.size());

        try {
            for (Object obj : collection) {
                list.add(PropertyUtils.getProperty(obj, propertyName));
            }
        } catch (Exception e) {
            throw Reflections.convertReflectionExceptionToUnchecked(e);
        }

        return list;
    }

    /**
     * ????(Getter), ??.
     * 
     * @param collection ???.
     * @param propertyName ??????.
     * @param separator .
     */
    public static String extractToString(final Collection collection, final String propertyName,
            final String separator) {
        List list = extractToList(collection, propertyName);
        return StringUtils.join(list, separator);
    }

    /**
     * ?Collection(toString())String,  separator
     */
    public static String convertToString(final Collection collection, final String separator) {
        return StringUtils.join(collection, separator);
    }

    /**
     * ?Collection(toString())String, ???prefix??postfix<div>mymessage</div>
     */
    public static String convertToString(final Collection collection, final String prefix, final String postfix) {
        StringBuilder builder = new StringBuilder();
        for (Object o : collection) {
            builder.append(prefix).append(o).append(postfix);
        }
        return builder.toString();
    }

    /**
     * ?.
     */
    public static boolean isEmpty(Collection collection) {
        return (collection == null || collection.isEmpty());
    }

    /**
     * ?Collectioncollectionnull.
     */
    public static <T> T getFirst(Collection<T> collection) {
        if (isEmpty(collection)) {
            return null;
        }

        return collection.iterator().next();
    }

    /**
     * ?Collection? collectionnull.
     */
    public static <T> T getLast(Collection<T> collection) {
        if (isEmpty(collection)) {
            return null;
        }

        // List?? 
        if (collection instanceof List) {
            List<T> list = (List<T>) collection;
            return list.get(list.size() - 1);
        }

        // iterator?.
        Iterator<T> iterator = collection.iterator();
        while (true) {
            T current = iterator.next();
            if (!iterator.hasNext()) {
                return current;
            }
        }
    }

    /**
     * a+bList.
     */
    public static <T> List<T> union(final Collection<T> a, final Collection<T> b) {
        List<T> result = Lists.newArrayList(a);
        result.addAll(b);
        return result;
    }

    /**
     * a-bList.
     */
    public static <T> List<T> subtract(final Collection<T> a, final Collection<T> b) {
        List<T> list = Lists.newArrayList(a);
        for (T element : b) {
            list.remove(element);
        }

        return list;
    }

    /**
     * abList.
     */
    public static <T> List<T> intersection(Collection<T> a, Collection<T> b) {
        List<T> list = Lists.newArrayList();

        for (T element : a) {
            if (b.contains(element)) {
                list.add(element);
            }
        }
        return list;
    }

    /**
     * copy list?
     * 
     * @param source ?list
     * @param destinationClass 
     * @return
     */
    public static <E> List<E> copyTo(List<?> source, Class<E> destinationClass) {
        if (source.size() == 0)
            return Collections.emptyList();
        List<E> res = new ArrayList<E>();
        try {
            for (Object o : source) {
                E e = destinationClass.newInstance();
                BeanUtils.copyProperties(e, o);
                res.add(e);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return res;
    }

    /**
     * map?bean
     *
     * @param map
     * @param beanClass
     * @return
     */
    public static Object map2Bean(Map map, Class<?> beanClass) {
        try {
            Object bean = beanClass.newInstance();
            PropertyUtils.copyProperties(bean, map);
            return bean;
        } catch (Exception e) {
            throw new RuntimeException(beanClass.getCanonicalName() + "!");
        }
    }

    /**
     * mapList?beanList
     *
     * @param mapList
     * @param beanClass
     * @return
     */
    @SuppressWarnings("unchecked")
    public static List<?> maplist2BeanList(List<Map<String, Object>> mapList, Class<?> beanClass) {
        List list = new ArrayList<Object>(mapList.size());
        for (Map map : mapList) {
            list.add(map2Bean(map, beanClass));
        }
        return list;
    }

    public static <T extends BaseEntity> List<T> maplist2EntityMapList(List<Map<String, Object>> mapList,
            Class<T> beanClass) {
        List<T> newList = Lists.newArrayList();
        for (Map<String, Object> map : mapList) {
            try {
                T t = beanClass.newInstance();
                t.setAll(map);
                newList.add(t);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return newList;
    }

}