SQL: Fix checkstyle / add missing hashCode (elastic/x-pack-elasticsearch#3323)

* Fix checkstyle / add missing hashCode
* Improve formatting

Original commit: elastic/x-pack-elasticsearch@a3ad2793bb

dev-tools/checkstyle_suppressions.xml

@@ -9,7 +9,6 @@
   <suppress files="sql[/\\]server[/\\]src[/\\]main[/\\]java[/\\]org[/\\]elasticsearch[/\\]xpack[/\\]sql[/\\]parser[/\\]SqlBase(Base(Listener|Visitor)|Lexer|Listener|Parser|Visitor).java" checks="." />
 
   <suppress files="sql[/\\]server[/\\].*.java" checks="LineLength" />
-  <suppress files="sql[/\\]server[/\\]src[/\\]main[/\\]java[/\\]org[/\\]elasticsearch[/\\]xpack[/\\]sql[/\\]expression[/\\].*.java" checks="EqualsHashCode" />
 
   <suppress files="plugin[/\\]src[/\\]main[/\\]java[/\\]org[/\\]elasticsearch[/\\]xpack[/\\]common[/\\]action[/\\]XPackDeleteByQueryAction.java" checks="LineLength" />
   <suppress files="plugin[/\\]src[/\\]main[/\\]java[/\\]org[/\\]elasticsearch[/\\]xpack[/\\]ml[/\\]action[/\\]StopDatafeedAction.java" checks="LineLength" />

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/Attribute.java

@@ -43,6 +43,7 @@ public abstract class Attribute extends NamedExpression {
         return qualifier == null ? name() : qualifier + "." + name();
     }
 
+    @Override
     public boolean nullable() {
         return nullable;
     }
@@ -89,6 +90,22 @@ public abstract class Attribute extends NamedExpression {
         return other instanceof Attribute ? id().equals(((Attribute) other).id()) : false;
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), qualifier, nullable);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (super.equals(obj)) {
+            Attribute other = (Attribute) obj;
+            return Objects.equals(qualifier, other.qualifier) 
+                    && Objects.equals(nullable, other.nullable);
+        }
+
+        return false;
+    }
+
     @Override
     public String toString() {
         return name() + "{" + label() + "}" + "#" + id();

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/TypedAttribute.java

@@ -5,11 +5,11 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
-import java.util.Objects;
-
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.type.DataType;
 
+import java.util.Objects;
+
 public abstract class TypedAttribute extends Attribute {
 
     private final DataType dataType;
@@ -29,21 +29,17 @@ public abstract class TypedAttribute extends Attribute {
     }
 
     @Override
-    public boolean equals(Object obj) {
+    public int hashCode() {
-        if (this == obj) {
+        return Objects.hash(super.hashCode(), dataType);
-            return true;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (super.equals(obj)) {
+            TypedAttribute other = (TypedAttribute) obj;
+            return Objects.equals(dataType, other.dataType);
         }
 
-        if (obj == null || getClass() != obj.getClass()) {
         return false;
     }
-        
-        TypedAttribute other = (TypedAttribute) obj;
-        return Objects.equals(name(), other.name())
-                && Objects.equals(id(), other.id())
-                && Objects.equals(nullable(), other.nullable())
-                && Objects.equals(dataType(), other.dataType())
-                && Objects.equals(qualifier(), other.qualifier())
-                && Objects.equals(synthetic(), other.synthetic());
-    }
 }

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/UnresolvedAlias.java

@@ -34,18 +34,14 @@ public class UnresolvedAlias extends UnresolvedNamedExpression {
         throw new UnresolvedException("nullable", this);
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), child);
+    }
+
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) {
+        return super.equals(obj) && Objects.equals(child, ((UnresolvedAlias) obj).child);
-            return true;
-        }
-
-        if (obj == null || getClass() != obj.getClass()) {
-            return false;
-        }
-
-        UnresolvedAlias other = (UnresolvedAlias) obj;
-        return Objects.equals(child, other.child);
     }
 
     @Override

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/UnresolvedAttribute.java

@@ -92,6 +92,11 @@ public class UnresolvedAttribute extends Attribute implements Unresolvable {
         return msg;
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), resolutionMetadata, unresolvedMsg);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (super.equals(obj)) {

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/UnresolvedStar.java

@@ -31,20 +31,21 @@ public class UnresolvedStar extends UnresolvedNamedExpression {
         return qualifier;
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), qualifier);
+    }
+
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) {
+        if (super.equals(obj)) {
-            return true;
-        }
-
-        if (obj == null || getClass() != obj.getClass()) {
-            return false;
-        }
-
             UnresolvedStar other = (UnresolvedStar) obj;
             return Objects.equals(qualifier, other.qualifier);
         }
 
+        return false;
+    }
+
     private String message() {
         return (qualifier() != null ? qualifier() + "." : "") + "*";
     }

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/function/FunctionAttribute.java

@@ -26,6 +26,11 @@ public abstract class FunctionAttribute extends TypedAttribute {
         return functionId;
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), functionId);
+    }
+
     @Override
     public boolean equals(Object obj) {
         return super.equals(obj) && Objects.equals(functionId, ((FunctionAttribute) obj).functionId());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/function/aggregate/AggregateFunctionAttribute.java

@@ -47,6 +47,11 @@ public class AggregateFunctionAttribute extends FunctionAttribute {
         return new AggregateFunctionAttribute(location(), name(), dataType(), qualifier(), nullable(), id(), synthetic(), functionId, propertyPath);
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), propertyPath);
+    }
+
     @Override
     public boolean equals(Object obj) {
         return super.equals(obj) && Objects.equals(propertyPath(), ((AggregateFunctionAttribute) obj).propertyPath());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/Cast.java

@@ -77,6 +77,11 @@ public class Cast extends UnaryScalarFunction {
         return new UnaryProcessorDefinition(this, ProcessorDefinitions.toProcessorDefinition(field()), new CastProcessor(DataTypeConversion.conversionFor(from(), to())));
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), dataType);
+    }
+
     @Override
     public boolean equals(Object obj) {
         return super.equals(obj) && Objects.equals(dataType, ((Cast) obj).dataType());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/ScalarFunctionAttribute.java

@@ -59,6 +59,11 @@ public class ScalarFunctionAttribute extends FunctionAttribute {
                 processorDef);
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), orderBy);
+    }
+
     @Override
     public boolean equals(Object obj) {
         return super.equals(obj) && Objects.equals(orderBy, ((ScalarFunctionAttribute) obj).orderBy());