Expand collection in GroupAggregator?

Question

Let's say I have an object in my cache with this method declared on it:
    public Collection getListOfStuff() { . . . }If I do this:
    GroupAggregator groupBy = GroupAggregator.createInstance("getListOfStuff", new Count());
    Map results = (Map) cache.aggregate((Filter) null, groupBy);I'll get counts of how many time each combination of stuff in the collection returned by getListOfStuff appears.
What if I want to break out the individual elements in the collection before counting it? E.g., If I have two objects, one where getListOfStuff returns {noformat}["foo", "bar"]{noformat} and the other where it returns {noformat}["bar", "batz"]{noformat}
I'd like to get the result:
"foo" = 1;
"bar" = 2;
"batz" = 1;
instead of:
["foo", "bar"] = 1;
["bar", "batz"] = 1;
I don't see an easy way to do this. Is there one?
Thanks.

Answer 1

Hi timberwolf,
You can write your own:
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
import com.tangosol.util.Base;
import com.tangosol.util.Filter;
import com.tangosol.util.InvocableMap;
import com.tangosol.util.ValueExtractor;
import com.tangosol.util.extractor.IdentityExtractor;
import com.tangosol.util.extractor.ReflectionExtractor;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
* dimitri
public class Main extends Base
    public static class MyAggregator implements InvocableMap.ParallelAwareAggregator
        public MyAggregator(String sMethodName)
            this(new ReflectionExtractor(sMethodName));
        public MyAggregator(ValueExtractor extractor)
            m_extractor = extractor;
        public InvocableMap.EntryAggregator getParallelAggregator()
            return this;
        public Object aggregateResults(Collection collResults)
            Map mapResult = new HashMap();
            for (Iterator iter = collResults.iterator(); iter.hasNext(); )
                Map mapPartial = (Map) iter.next();
                for (Iterator iterPartial = mapPartial.entrySet().iterator(); iterPartial.hasNext(); )
                    Map.Entry entry      = (Map.Entry) iterPartial.next();
                    Object    oKey       = entry.getKey();
                    int       cIncrement = ((Integer)entry.getValue()).intValue();
                    mapIncrement(mapResult, oKey, cIncrement);
            return mapResult;
        public Object aggregate(Set setEntries)
            Map            mapResults = new HashMap();
            ValueExtractor extractor  = m_extractor;
            for (Iterator iter = setEntries.iterator(); iter.hasNext(); )
                InvocableMap.Entry entry = (InvocableMap.Entry) iter.next();
                if (entry.isPresent())
                    Collection coll = (Collection) entry.extract(extractor);
                    for (Iterator iterExtracted = coll.iterator(); iterExtracted.hasNext(); )
                        mapIncrement(mapResults, iterExtracted.next(), 1);
            return mapResults;
        void mapIncrement(Map map, Object oKey, int cIncrement)
            Integer iValue = (Integer)map.get(oKey);
            iValue = iValue == null ? makeInteger(cIncrement) : makeInteger(iValue.intValue() + cIncrement);
            map.put(oKey, iValue);
        ValueExtractor m_extractor;
    public static void main(String[] asArg)
        try
            NamedCache cache = CacheFactory.getCache("test");
            cache.addIndex(IdentityExtractor.INSTANCE, false, null);
            Collection coll  = new ArrayList();
            coll.add("foo");
            coll.add("bar");
            cache.put("a", coll);
            coll.clear();
            coll.add("bar");
            coll.add("batz");
            cache.put("b", coll);
            Map  mapResult = (Map) cache.aggregate((Filter)null, new MyAggregator(IdentityExtractor.INSTANCE));
            System.out.println(mapResult);
        catch (Throwable oops)
            err(oops);
        finally
            CacheFactory.shutdown();
    }Regards,
Dimitri