Make the Query DTO equatable/hashable (#83)

* Make the Query DTO equatable/hashable

Author: suresh-prakash

document-store/src/main/java/org/hypertrace/core/documentstore/expression/model/Hashable.java

@@ -0,0 +1,9 @@
+package org.hypertrace.core.documentstore.expression.model;
+
+public interface Hashable {
+  @Override
+  int hashCode();
+
+  @Override
+  boolean equals(final Object object);
+}

document-store/src/main/java/org/hypertrace/core/documentstore/expression/type/FilterTypeExpression.java

@@ -1,11 +1,12 @@
 package org.hypertrace.core.documentstore.expression.type;
 
+import org.hypertrace.core.documentstore.expression.model.Hashable;
 import org.hypertrace.core.documentstore.parser.FilterTypeExpressionVisitor;
 
 /**
  * An interface to represent that the expression can be used in either the WHERE clause or the
  * HAVING clause of the query.
  */
-public interface FilterTypeExpression {
+public interface FilterTypeExpression extends Hashable {
   <T> T accept(final FilterTypeExpressionVisitor visitor);
 }

document-store/src/main/java/org/hypertrace/core/documentstore/expression/type/FromTypeExpression.java

@@ -1,11 +1,12 @@
 package org.hypertrace.core.documentstore.expression.type;
 
+import org.hypertrace.core.documentstore.expression.model.Hashable;
 import org.hypertrace.core.documentstore.parser.FromTypeExpressionVisitor;
 
 /**
  * Expression to retrieve rows from the referenced tables Implementations can perform table
  * functions, join, lateral subqueries
  */
-public interface FromTypeExpression {
+public interface FromTypeExpression extends Hashable {
   <T> T accept(final FromTypeExpressionVisitor visitor);
 }

document-store/src/main/java/org/hypertrace/core/documentstore/expression/type/GroupTypeExpression.java

@@ -1,10 +1,11 @@
 package org.hypertrace.core.documentstore.expression.type;
 
+import org.hypertrace.core.documentstore.expression.model.Hashable;
 import org.hypertrace.core.documentstore.parser.GroupTypeExpressionVisitor;
 
 /**
  * An interface to represent that the expression can be used in the GROUP BY clause of the query.
  */
-public interface GroupTypeExpression {
+public interface GroupTypeExpression extends Hashable {
   <T> T accept(final GroupTypeExpressionVisitor visitor);
 }

document-store/src/main/java/org/hypertrace/core/documentstore/expression/type/SelectTypeExpression.java

@@ -1,8 +1,9 @@
 package org.hypertrace.core.documentstore.expression.type;
 
+import org.hypertrace.core.documentstore.expression.model.Hashable;
 import org.hypertrace.core.documentstore.parser.SelectTypeExpressionVisitor;
 
 /** An interface to represent that the expression can be used in the SELECT clause of the query. */
-public interface SelectTypeExpression {
+public interface SelectTypeExpression extends Hashable {
   <T> T accept(final SelectTypeExpressionVisitor visitor);
 }

document-store/src/main/java/org/hypertrace/core/documentstore/expression/type/SortTypeExpression.java

@@ -1,10 +1,11 @@
 package org.hypertrace.core.documentstore.expression.type;
 
+import org.hypertrace.core.documentstore.expression.model.Hashable;
 import org.hypertrace.core.documentstore.parser.SortTypeExpressionVisitor;
 
 /**
  * An interface to represent that the expression can be used in the ORDER BY clause of the query.
  */
-public interface SortTypeExpression {
+public interface SortTypeExpression extends Hashable {
   <T> T accept(final SortTypeExpressionVisitor visitor);
 }

document-store/src/main/java/org/hypertrace/core/documentstore/query/Query.java

@@ -8,7 +8,7 @@
 import lombok.AccessLevel;
 import lombok.AllArgsConstructor;
 import lombok.NoArgsConstructor;
-import lombok.ToString;
+import lombok.Value;
 import org.apache.commons.collections4.CollectionUtils;
 import org.hypertrace.core.documentstore.expression.operators.SortOrder;
 import org.hypertrace.core.documentstore.expression.type.FilterTypeExpression;
@@ -67,15 +67,15 @@
  *  </code>
  */
 @AllArgsConstructor(access = AccessLevel.PACKAGE)
-@ToString
-public final class Query {
-  private final Selection selection; // Missing selection represents fetching all the columns
-  private final Filter filter;
-  private final Aggregation aggregation;
-  private final Filter aggregationFilter;
-  private final Sort sort;
-  private final Pagination pagination; // Missing pagination represents fetching all the records
-  private final FromClause fromClause;
+@Value
+public class Query {
+  Selection selection; // Missing selection represents fetching all the columns
+  Filter filter;
+  Aggregation aggregation;
+  Filter aggregationFilter;
+  Sort sort;
+  Pagination pagination; // Missing pagination represents fetching all the records
+  FromClause fromClause;
 
   public List<SelectionSpec> getSelections() {
     return selection == null ? emptyList() : unmodifiableList(selection.getSelectionSpecs());