Math expressional parameters for 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/Evals.java

@@ -0,0 +1,43 @@
+/*
+ * Licensed to Metamarkets Group Inc. (Metamarkets) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Metamarkets licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package io.druid.math.expr;
+
+import com.google.common.primitives.Longs;
+
+/**
+ */
+public class Evals
+{
+  public static Number toNumber(Object value)
+  {
+    if (value == null) {
+      return 0L;
+    }
+    if (value instanceof Number) {
+      return (Number) value;
+    }
+    String stringValue = String.valueOf(value);
+    Long longValue = Longs.tryParse(stringValue);
+    if (longValue == null) {
+      return Double.valueOf(stringValue);
+    }
+    return longValue;
+  }
+}

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

@@ -22,16 +22,36 @@
 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(ObjectBinding bindings);
+
+  interface ObjectBinding
+  {
+    Number get(String name);
+  }
+
+  void visit(Visitor visitor);
+
+  interface Visitor
+  {
+    void visit(Expr expr);
+  }
+}
+
+abstract class ConstantExpr implements Expr
+{
+  @Override
+  public void visit(Visitor visitor)
+  {
+    visitor.visit(this);
+  }
 }
 
-class LongExpr implements Expr
+class LongExpr extends ConstantExpr
 {
   private final long value;
 
@@ -47,13 +67,13 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     return value;
   }
 }
 
-class DoubleExpr implements Expr
+class DoubleExpr extends ConstantExpr
 {
   private final double value;
 
@@ -69,13 +89,13 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     return value;
   }
 }
 
-class IdentifierExpr implements Expr
+class IdentifierExpr extends ConstantExpr
 {
   private final String value;
 
@@ -91,7 +111,7 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number val = bindings.get(value);
     if (val == null) {
@@ -104,8 +124,8 @@ 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 +140,47 @@ public String toString()
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     return Parser.func.get(name.toLowerCase()).apply(args, bindings);
   }
+
+  @Override
+  public void visit(Visitor visitor)
+  {
+    for (Expr child : args) {
+      child.visit(visitor);
+    }
+    visitor.visit(this);
+  }
 }
 
-class UnaryMinusExpr implements Expr
+abstract class UnaryExpr implements Expr
 {
-  private final Expr expr;
+  final Expr expr;
 
-  UnaryMinusExpr(Expr expr)
+  UnaryExpr(Expr expr)
   {
     this.expr = expr;
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public void visit(Visitor visitor)
+  {
+    expr.visit(visitor);
+    visitor.visit(this);
+  }
+}
+
+class UnaryMinusExpr extends UnaryExpr
+{
+  UnaryMinusExpr(Expr expr)
+  {
+    super(expr);
+  }
+
+  @Override
+  public Number eval(ObjectBinding bindings)
   {
     Number valObj = expr.eval(bindings);
     if (valObj instanceof Long) {
@@ -146,24 +190,29 @@ public Number eval(Map<String, Number> bindings)
     }
   }
 
+  @Override
+  public void visit(Visitor visitor)
+  {
+    expr.visit(visitor);
+    visitor.visit(this);
+  }
+
   @Override
   public String toString()
   {
     return "-" + expr.toString();
   }
 }
 
-class UnaryNotExpr implements Expr
+class UnaryNotExpr extends UnaryExpr
 {
-  private final Expr expr;
-
   UnaryNotExpr(Expr expr)
   {
-    this.expr = expr;
+    super(expr);
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number valObj = expr.eval(bindings);
     return valObj.doubleValue() > 0 ? 0.0d : 1.0d;
@@ -194,6 +243,14 @@ protected boolean isLong(Number left, Number right)
     return left instanceof Long && right instanceof Long;
   }
 
+  @Override
+  public void visit(Visitor visitor)
+  {
+    left.visit(visitor);
+    right.visit(visitor);
+    visitor.visit(this);
+  }
+
   @Override
   public String toString()
   {
@@ -210,7 +267,7 @@ class BinMinusExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -231,7 +288,7 @@ class BinPowExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -252,7 +309,7 @@ class BinMulExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -273,7 +330,7 @@ class BinDivExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -294,7 +351,7 @@ class BinModuloExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -315,7 +372,7 @@ class BinPlusExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -336,7 +393,7 @@ class BinLtExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -357,7 +414,7 @@ class BinLeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -378,7 +435,7 @@ class BinGtExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -399,7 +456,7 @@ class BinGeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -420,7 +477,7 @@ class BinEqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -441,7 +498,7 @@ class BinNeqExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -462,7 +519,7 @@ class BinAndExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);
@@ -495,7 +552,7 @@ class BinOrExpr extends BinaryOpExprBase
   }
 
   @Override
-  public Number eval(Map<String, Number> bindings)
+  public Number eval(ObjectBinding bindings)
   {
     Number leftVal = left.eval(bindings);
     Number rightVal = right.eval(bindings);