making AggregatorFactory abstract class

extensions/histogram/src/main/java/io/druid/query/aggregation/histogram/ApproximateHistogramAggregatorFactory.java

@@ -39,7 +39,7 @@ import java.util.Comparator;
 import java.util.List;
 
 @JsonTypeName("approxHistogram")
-public class ApproximateHistogramAggregatorFactory implements AggregatorFactory
+public class ApproximateHistogramAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x8;
 

processing/src/main/java/io/druid/query/aggregation/AggregatorFactory.java

@@ -34,13 +34,13 @@ import java.util.List;
  * provided to the Aggregator through the MetricSelector object, so whatever creates that object gets to choose how
  * the data is actually stored and accessed.
  */
-public interface AggregatorFactory
+public abstract class AggregatorFactory
 {
-  public Aggregator factorize(ColumnSelectorFactory metricFactory);
+  public abstract Aggregator factorize(ColumnSelectorFactory metricFactory);
 
-  public BufferAggregator factorizeBuffered(ColumnSelectorFactory metricFactory);
+  public abstract BufferAggregator factorizeBuffered(ColumnSelectorFactory metricFactory);
 
-  public Comparator getComparator();
+  public abstract Comparator getComparator();
 
   /**
    * A method that knows how to combine the outputs of the getIntermediate() method from the Aggregators
@@ -53,7 +53,7 @@ public interface AggregatorFactory
    *
    * @return an object representing the combination of lhs and rhs, this can be a new object or a mutation of the inputs
    */
-  public Object combine(Object lhs, Object rhs);
+  public abstract Object combine(Object lhs, Object rhs);
 
   /**
    * Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory.  This
@@ -62,14 +62,14 @@ public interface AggregatorFactory
    *
    * @return a new Factory that can be used for operations on top of data output from the current factory.
    */
-  public AggregatorFactory getCombiningFactory();
+  public abstract AggregatorFactory getCombiningFactory();
 
   /**
    * Gets a list of all columns that this AggregatorFactory will scan
    *
    * @return AggregatorFactories for the columns to scan of the parent AggregatorFactory
    */
-  public List<AggregatorFactory> getRequiredColumns();
+  public abstract List<AggregatorFactory> getRequiredColumns();
 
   /**
    * A method that knows how to "deserialize" the object from whatever form it might have been put into
@@ -79,7 +79,7 @@ public interface AggregatorFactory
    *
    * @return the deserialized object
    */
-  public Object deserialize(Object object);
+  public abstract Object deserialize(Object object);
 
   /**
    * "Finalizes" the computation of an object.  Primarily useful for complex types that have a different mergeable
@@ -89,27 +89,27 @@ public interface AggregatorFactory
    *
    * @return the finalized value that should be returned for the initial query
    */
-  public Object finalizeComputation(Object object);
+  public abstract Object finalizeComputation(Object object);
 
-  public String getName();
+  public abstract String getName();
 
-  public List<String> requiredFields();
+  public abstract List<String> requiredFields();
 
-  public byte[] getCacheKey();
+  public abstract byte[] getCacheKey();
 
-  public String getTypeName();
+  public abstract String getTypeName();
 
   /**
    * Returns the maximum size that this aggregator will require in bytes for intermediate storage of results.
    *
    * @return the maximum number of bytes that an aggregator of this type will require for intermediate result storage.
    */
-  public int getMaxIntermediateSize();
+  public abstract int getMaxIntermediateSize();
 
   /**
    * Returns the starting value for a corresponding aggregator. For example, 0 for sums, - Infinity for max, an empty mogrifier
    *
    * @return the starting value for a corresponding aggregator.
    */
-  public Object getAggregatorStartValue();
+  public abstract Object getAggregatorStartValue();
 }

processing/src/main/java/io/druid/query/aggregation/CountAggregatorFactory.java

@@ -32,7 +32,7 @@ import java.util.List;
 
 /**
  */
-public class CountAggregatorFactory implements AggregatorFactory
+public class CountAggregatorFactory extends AggregatorFactory
 {
   private static final byte[] CACHE_KEY = new byte[]{0x0};
   private final String name;

processing/src/main/java/io/druid/query/aggregation/DoubleMaxAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class DoubleMaxAggregatorFactory implements AggregatorFactory
+public class DoubleMaxAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x3;
 

processing/src/main/java/io/druid/query/aggregation/DoubleMinAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class DoubleMinAggregatorFactory implements AggregatorFactory
+public class DoubleMinAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x4;
 

processing/src/main/java/io/druid/query/aggregation/DoubleSumAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class DoubleSumAggregatorFactory implements AggregatorFactory
+public class DoubleSumAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x2;
 

processing/src/main/java/io/druid/query/aggregation/FilteredAggregatorFactory.java

@@ -30,7 +30,7 @@ import java.nio.ByteBuffer;
 import java.util.Comparator;
 import java.util.List;
 
-public class FilteredAggregatorFactory implements AggregatorFactory
+public class FilteredAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x9;
 

processing/src/main/java/io/druid/query/aggregation/HistogramAggregatorFactory.java

@@ -34,7 +34,7 @@ import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 
-public class HistogramAggregatorFactory implements AggregatorFactory
+public class HistogramAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x7;
 

processing/src/main/java/io/druid/query/aggregation/JavaScriptAggregatorFactory.java

@@ -42,7 +42,7 @@ import java.security.NoSuchAlgorithmException;
 import java.util.Comparator;
 import java.util.List;
 
-public class JavaScriptAggregatorFactory implements AggregatorFactory
+public class JavaScriptAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x6;
 

processing/src/main/java/io/druid/query/aggregation/LongMaxAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class LongMaxAggregatorFactory implements AggregatorFactory
+public class LongMaxAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0xA;
 

processing/src/main/java/io/druid/query/aggregation/LongMinAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class LongMinAggregatorFactory implements AggregatorFactory
+public class LongMinAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0xB;
 

processing/src/main/java/io/druid/query/aggregation/LongSumAggregatorFactory.java

@@ -33,7 +33,7 @@ import java.util.List;
 
 /**
  */
-public class LongSumAggregatorFactory implements AggregatorFactory
+public class LongSumAggregatorFactory extends AggregatorFactory
 {
   private static final byte CACHE_TYPE_ID = 0x1;
 

processing/src/main/java/io/druid/query/aggregation/cardinality/CardinalityAggregatorFactory.java

@@ -43,7 +43,7 @@ import java.nio.ByteBuffer;
 import java.util.Comparator;
 import java.util.List;
 
-public class CardinalityAggregatorFactory implements AggregatorFactory
+public class CardinalityAggregatorFactory extends AggregatorFactory
 {
   public static Object estimateCardinality(Object object)
   {

processing/src/main/java/io/druid/query/aggregation/hyperloglog/HyperUniquesAggregatorFactory.java

@@ -38,7 +38,7 @@ import java.util.List;
 
 /**
  */
-public class HyperUniquesAggregatorFactory implements AggregatorFactory
+public class HyperUniquesAggregatorFactory extends AggregatorFactory
 {
   public static Object estimateCardinality(Object object)
   {