AggregatorFactory equals() and hashCode() methods.

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

@@ -238,6 +238,52 @@ public class ApproximateHistogramAggregatorFactory implements AggregatorFactory
     return new ApproximateHistogram(resolution);
   }
 
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    ApproximateHistogramAggregatorFactory that = (ApproximateHistogramAggregatorFactory) o;
+
+    if (Float.compare(that.lowerLimit, lowerLimit) != 0) {
+      return false;
+    }
+    if (numBuckets != that.numBuckets) {
+      return false;
+    }
+    if (resolution != that.resolution) {
+      return false;
+    }
+    if (Float.compare(that.upperLimit, upperLimit) != 0) {
+      return false;
+    }
+    if (fieldName != null ? !fieldName.equals(that.fieldName) : that.fieldName != null) {
+      return false;
+    }
+    if (name != null ? !name.equals(that.name) : that.name != null) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = name != null ? name.hashCode() : 0;
+    result = 31 * result + (fieldName != null ? fieldName.hashCode() : 0);
+    result = 31 * result + resolution;
+    result = 31 * result + numBuckets;
+    result = 31 * result + (lowerLimit != +0.0f ? Float.floatToIntBits(lowerLimit) : 0);
+    result = 31 * result + (upperLimit != +0.0f ? Float.floatToIntBits(upperLimit) : 0);
+    return result;
+  }
+
   @Override
   public String toString()
   {

histogram/src/main/java/io/druid/query/aggregation/histogram/ApproximateHistogramFoldingAggregatorFactory.java

@@ -148,6 +148,52 @@ public class ApproximateHistogramFoldingAggregatorFactory extends ApproximateHis
                      .array();
   }
 
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    ApproximateHistogramAggregatorFactory that = (ApproximateHistogramAggregatorFactory) o;
+
+    if (Float.compare(that.lowerLimit, lowerLimit) != 0) {
+      return false;
+    }
+    if (numBuckets != that.numBuckets) {
+      return false;
+    }
+    if (resolution != that.resolution) {
+      return false;
+    }
+    if (Float.compare(that.upperLimit, upperLimit) != 0) {
+      return false;
+    }
+    if (fieldName != null ? !fieldName.equals(that.fieldName) : that.fieldName != null) {
+      return false;
+    }
+    if (name != null ? !name.equals(that.name) : that.name != null) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = name != null ? name.hashCode() : 0;
+    result = 31 * result + (fieldName != null ? fieldName.hashCode() : 0);
+    result = 31 * result + resolution;
+    result = 31 * result + numBuckets;
+    result = 31 * result + (lowerLimit != +0.0f ? Float.floatToIntBits(lowerLimit) : 0);
+    result = 31 * result + (upperLimit != +0.0f ? Float.floatToIntBits(upperLimit) : 0);
+    return result;
+  }
+
   @Override
   public String toString()
   {

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

@@ -39,7 +39,6 @@ import org.apache.commons.codec.binary.Base64;
 
 import javax.annotation.Nullable;
 import java.nio.ByteBuffer;
-import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 
@@ -233,6 +232,40 @@ public class CardinalityAggregatorFactory implements AggregatorFactory
     return HyperLogLogCollector.makeLatestCollector();
   }
 
+  @Override
+  public boolean equals(Object o)
+  {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    CardinalityAggregatorFactory that = (CardinalityAggregatorFactory) o;
+
+    if (byRow != that.byRow) {
+      return false;
+    }
+    if (fieldNames != null ? !fieldNames.equals(that.fieldNames) : that.fieldNames != null) {
+      return false;
+    }
+    if (name != null ? !name.equals(that.name) : that.name != null) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @Override
+  public int hashCode()
+  {
+    int result = name != null ? name.hashCode() : 0;
+    result = 31 * result + (fieldNames != null ? fieldNames.hashCode() : 0);
+    result = 31 * result + (byRow ? 1 : 0);
+    return result;
+  }
+
   @Override
   public String toString()
   {