[WIP] Supports math expressional post aggregator

common/src/main/java/io/druid/common/utils/StringUtils.java

@@ -23,7 +23,7 @@
  */
 public class StringUtils extends com.metamx.common.StringUtils
 {
-  public static final String EMPTY = "";
+  private static final byte[] EMPTY_BYTES = new byte[0];
 
   // should be used only for estimation
   // returns the same result with StringUtils.fromUtf8(value).length for valid string values
@@ -46,4 +46,9 @@ public static int estimatedBinaryLengthAsUTF8(String value)
     }
     return length;
   }
+
+  public static byte[] toUtf8WithNullToEmpty(final String string)
+  {
+    return string == null ? EMPTY_BYTES : toUtf8(string);
+  }
 }

common/src/main/java/io/druid/math/expr/Expr.java

@@ -22,13 +22,17 @@
 import com.google.common.math.LongMath;
 
 import java.util.List;
-import java.util.Map;
 
 /**
  */
 public interface Expr
 {
-  Number eval(Map<String, Number> bindings);
+  Number eval(NumericBinding bindings);
+
+  interface NumericBinding
+  {
+    Number get(String name);
+  }
 }
 
 class LongExpr implements Expr
@@ -47,7 +51,7 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     return value;
   }
@@ -69,7 +73,7 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     return value;
   }
@@ -91,7 +95,7 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number val = bindings.get(value);
     if (val == null) {
@@ -104,8 +108,8 @@ public Number eval(Map<String, Number> bindings)
 
 class FunctionExpr implements Expr
 {
-  private final String name;
-  private final List<Expr> args;
+  final String name;
+  final List<Expr> args;
 
   public FunctionExpr(String name, List<Expr> args)
   {
@@ -120,23 +124,23 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     return Parser.func.get(name.toLowerCase()).apply(args, bindings);
   }
 }
 
 class UnaryMinusExpr implements Expr
 {
-  private final Expr expr;
+  final Expr expr;
 
   UnaryMinusExpr(Expr expr)
   {
     this.expr = expr;
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number valObj = expr.eval(bindings);
     if (valObj instanceof Long) {
@@ -155,15 +159,15 @@ public String toString()
 
 class UnaryNotExpr implements Expr
 {
-  private final Expr expr;
+  final Expr expr;
 
   UnaryNotExpr(Expr expr)
   {
     this.expr = expr;
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number valObj = expr.eval(bindings);
     return valObj.doubleValue() > 0 ? 0.0d : 1.0d;
@@ -210,7 +214,7 @@ class BinMinusExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -231,7 +235,7 @@ class BinPowExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -252,7 +256,7 @@ class BinMulExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -273,7 +277,7 @@ class BinDivExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -294,7 +298,7 @@ class BinModuloExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -315,7 +319,7 @@ class BinPlusExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -336,7 +340,7 @@ class BinLtExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -357,7 +361,7 @@ class BinLeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -378,7 +382,7 @@ class BinGtExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -399,7 +403,7 @@ class BinGeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -420,7 +424,7 @@ class BinEqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -441,7 +445,7 @@ class BinNeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -462,7 +466,7 @@ class BinAndExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -495,7 +499,7 @@ class BinOrExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(NumericBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);

common/src/main/java/io/druid/math/expr/Function.java

@@ -20,20 +20,19 @@
 package io.druid.math.expr;
 
 import java.util.List;
-import java.util.Map;
 
 /**
  */
 interface Function
 {
   String name();
 
-  Number apply(List<Expr> args, Map<String, Number> bindings);
+  Number apply(List<Expr> args, Expr.NumericBinding bindings);
 
   abstract class SingleParam implements Function
   {
     @Override
-    public Number apply(List<Expr> args, Map<String, Number> bindings)
+    public Number apply(List<Expr> args, Expr.NumericBinding bindings)
     {
       if (args.size() != 1) {
         throw new RuntimeException("function '" + name() + "' needs 1 argument");
@@ -48,7 +47,7 @@ public Number apply(List<Expr> args, Map<String, Number> bindings)
   abstract class DoubleParam implements Function
   {
     @Override
-    public Number apply(List<Expr> args, Map<String, Number> bindings)
+    public Number apply(List<Expr> args, Expr.NumericBinding bindings)
     {
       if (args.size() != 2) {
         throw new RuntimeException("function '" + name() + "' needs 1 argument");
@@ -616,7 +615,7 @@ public String name()
     }
 
     @Override
-    public Number apply(List<Expr> args, Map<String, Number> bindings)
+    public Number apply(List<Expr> args, Expr.NumericBinding bindings)
     {
       if (args.size() != 3) {
         throw new RuntimeException("function 'if' needs 3 argument");