combine to map values. - Java Collection Framework

Java examples for Collection Framework:Map

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Description

combine to map values.

Demo Code

/*******************************************************************************
 * Copyright (c) 2014-2-26 @author <a href="mailto:iffiff1@gmail.com">Tyler Chen</a>.
 * All rights reserved./*from  ww  w  .  ja  v  a2  s . co  m*/
 *
 * Contributors:
 *     <a href="mailto:iffiff1@gmail.com">Tyler Chen</a> - initial API and implementation
 ******************************************************************************/
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class Main{
    /**
     * <pre>
     * combine to map values.
     * Usage:
     * Map map1 = toMap("aaa", 123, "bbb", 123);
     * Map map2 = toMap("aaaa", 123, "bbb", toMap("AAA", "123", "BBBB", toMap("@@@", "333")));
     * System.out.println(combine(map1, map2));
     * Result:
     * {aaa=123, bbb={AAA=123, BBBB={@@@=333}}, aaaa=123}
     * </pre>
     * @param beCombineMap
     * @param toCombineMap
     * @return
     * @author <a href="mailto:iffiff1@gmail.com">Tyler Chen</a> 
     * @since Aug 28, 2015
     */
    public static Map combine(Map beCombineMap, Map toCombineMap) {
        List<Map> p1 = new ArrayList<Map>(128);
        List<Map> p2 = new ArrayList<Map>(128);
        {
            p1.add(beCombineMap);
            p2.add(toCombineMap);
        }
        while (!p2.isEmpty()) {
            Map map1 = p1.remove(p1.size() - 1);
            Map map2 = p2.remove(p2.size() - 1);
            for (Entry entry : (Set<Entry>) map2.entrySet()) {
                if (entry.getValue() instanceof Map) {
                    Object object = map1.get(entry.getKey());
                    if (object == null) {
                        object = new LinkedHashMap();
                        map1.put(entry.getKey(), object);
                        {
                            p1.add((Map) object);
                            p2.add((Map) entry.getValue());
                        }
                    } else if (!(object instanceof Map)) {
                        Logger.warn(FCS
                                .get("[MapHelper.combine][ISNOTMAP][{0}][Result will be overwrite]",
                                        entry.getKey()));
                        object = new LinkedHashMap();
                        map1.put(entry.getKey(), object);
                        {
                            p1.add((Map) object);
                            p2.add((Map) entry.getValue());
                        }
                    }
                } else {
                    map1.put(entry.getKey(), entry.getValue());
                }
            }
        }
        return beCombineMap;
    }
}

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