org.power.commons.lang.util.CollectionUtils.java Source code

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Here is the source code for org.power.commons.lang.util.CollectionUtils.java

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/*
 *    Copyright (c) 2015 Power Group.
 *     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.power.commons.lang.util;

import org.apache.commons.lang3.StringUtils;
import org.power.commons.lang.BasicConstant;

import java.io.IOException;
import java.util.*;

/**
 * @author Geiger
 */
public class CollectionUtils {
    /**
     * <code>List</code>
     * <p>
     * {@code createArrayList(args)}?????
     * {@code createArrayList(args)}
     * </p>
     */
    public static <T> List<T> asList(T... args) {
        if (args == null || args.length == 0) {
            return Collections.emptyList();
        } else {
            return Arrays.asList(args);
        }
    }

    /**
     * ?
     */
    public static String join(Iterable<?> objs, String sep) {
        StringBuilder buf = new StringBuilder();

        join(buf, objs, sep);

        return buf.toString();
    }

    /**
     * ?
     */
    public static void join(StringBuilder buf, Iterable<?> objs, String sep) {
        try {
            join((Appendable) buf, objs, sep);
        } catch (IOException e) {
            Assert.unexpectedException(e);
        }
    }

    /**
     * ?
     */
    public static void join(Appendable buf, Iterable<?> objs, String sep) throws IOException {
        if (objs == null) {
            return;
        }

        if (sep == null) {
            sep = BasicConstant.EMPTY_STRING;
        }

        for (Iterator<?> i = objs.iterator(); i.hasNext();) {
            buf.append(String.valueOf(i.next()));

            if (i.hasNext()) {
                buf.append(sep);
            }
        }
    }

    /**
     * ?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();
    }

    private static <T> void iterableToCollection(Iterable<? extends T> c, Collection<T> list) {
        for (T element : c) {
            list.add(element);
        }
    }

    public static boolean isEmpty(Collection collection) {
        if (collection != null) {
            return collection.isEmpty();
        } else {
            return true;
        }
    }

    public static boolean isEmpty(Map map) {
        if (map != null) {
            return map.isEmpty();
        } else {
            return true;
        }
    }

}