DATAMONGO-1093 - Added hashCode() and equals(…) in BasicQuery.

We now have equals(…) and hashCode(…) methods on BasicQuery. Previously we solely relied on Query.hashCode()/equals(…) which didn't consider the fields of BasicQuery.

Introduced equals verifier library to automatically test equals contracts.
Added some additional test cases to BasicQueryUnitTests.

Original pull request: #252.

spring-data-mongodb/pom.xml

@@ -18,11 +18,12 @@
 	<properties>
 		<validation>1.0.0.GA</validation>
 		<objenesis>1.3</objenesis>
+		<equalsverifier>1.5</equalsverifier>
 	</properties>
 
 	<dependencies>
 
-		<!--  Spring -->
+		<!-- Spring -->
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-tx</artifactId>
@@ -50,7 +51,7 @@
 			<artifactId>spring-expression</artifactId>
 		</dependency>
 
-		<!--  Spring Data -->
+		<!-- Spring Data -->
 		<dependency>
 			<groupId>${project.groupId}</groupId>
 			<artifactId>spring-data-commons</artifactId>
@@ -144,6 +145,12 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>nl.jqno.equalsverifier</groupId>
+			<artifactId>equalsverifier</artifactId>
+			<version>${equalsverifier}</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/BasicQuery.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.mongodb.core.query;
 
+import static org.springframework.util.ObjectUtils.*;
+
 import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;
 import com.mongodb.util.JSON;
@@ -25,6 +27,7 @@ import com.mongodb.util.JSON;
  * @author Thomas Risberg
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Thomas Darimont
  */
 public class BasicQuery extends Query {
 
@@ -97,4 +100,42 @@ public class BasicQuery extends Query {
 	protected void setFieldsObject(DBObject fieldsObject) {
 		this.fieldsObject = fieldsObject;
 	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.query.Query#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object o) {
+
+		if (this == o) {
+			return true;
+		}
+
+		if (!(o instanceof BasicQuery)) {
+			return false;
+		}
+
+		BasicQuery that = (BasicQuery) o;
+
+		return querySettingsEquals(that) && //
+				nullSafeEquals(fieldsObject, that.fieldsObject) && //
+				nullSafeEquals(queryObject, that.queryObject) && //
+				nullSafeEquals(sortObject, that.sortObject);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.query.Query#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+
+		int result = super.hashCode();
+		result = 31 * result + nullSafeHashCode(queryObject);
+		result = 31 * result + nullSafeHashCode(fieldsObject);
+		result = 31 * result + nullSafeHashCode(sortObject);
+
+		return result;
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Query.java

@@ -385,12 +385,21 @@ public class Query {
 			return false;
 		}
 
-		Query that = (Query) obj;
+		return querySettingsEquals((Query) obj);
+	}
+
+	/**
+	 * Tests whether the settings of the given {@link Query} are equal to this query.
+	 * 
+	 * @param that
+	 * @return
+	 */
+	protected boolean querySettingsEquals(Query that) {
 
 		boolean criteriaEqual = this.criteria.equals(that.criteria);
-		boolean fieldsEqual = this.fieldSpec == null ? that.fieldSpec == null : this.fieldSpec.equals(that.fieldSpec);
-		boolean sortEqual = this.sort == null ? that.sort == null : this.sort.equals(that.sort);
-		boolean hintEqual = this.hint == null ? that.hint == null : this.hint.equals(that.hint);
+		boolean fieldsEqual = nullSafeEquals(this.fieldSpec, that.fieldSpec);
+		boolean sortEqual = nullSafeEquals(this.sort, that.sort);
+		boolean hintEqual = nullSafeEquals(this.hint, that.hint);
 		boolean skipEqual = this.skip == that.skip;
 		boolean limitEqual = this.limit == that.limit;
 		boolean metaEqual = nullSafeEquals(this.meta, that.meta);

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/query/BasicQueryUnitTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@ package org.springframework.data.mongodb.core.query;
 import static org.hamcrest.CoreMatchers.*;
 import static org.junit.Assert.*;
 import static org.springframework.data.mongodb.core.query.Criteria.*;
+import nl.jqno.equalsverifier.EqualsVerifier;
+import nl.jqno.equalsverifier.Warning;
 
 import org.junit.Test;
 import org.springframework.data.domain.Sort.Direction;
@@ -29,6 +31,7 @@ import com.mongodb.DBObject;
  * Unit tests for {@link BasicQuery}.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class BasicQueryUnitTests {
 
@@ -58,4 +61,80 @@ public class BasicQueryUnitTests {
 		sortReference.put("lastname", 1);
 		assertThat(query.getSortObject(), is(sortReference));
 	}
+
+	/**
+	 * @see DATAMONGO-1093
+	 */
+	@Test
+	public void equalsContract() {
+
+		BasicQuery query1 = new BasicQuery("{ \"name\" : \"Thomas\"}", "{\"name\":1, \"age\":1}");
+		query1.setSortObject(new BasicDBObject("name", -1));
+
+		BasicQuery query2 = new BasicQuery("{ \"name\" : \"Oliver\"}", "{\"name\":1, \"address\":1}");
+		query2.setSortObject(new BasicDBObject("name", 1));
+
+		EqualsVerifier.forExamples(query1, query2) //
+				.withRedefinedSuperclass() //
+				.suppress(Warning.NONFINAL_FIELDS, Warning.NULL_FIELDS, Warning.STRICT_INHERITANCE) //
+				.verify();
+	}
+
+	/**
+	 * @see DATAMONGO-1093
+	 */
+	@Test
+	public void handlesEqualsAndHashCodeCorrectlyForExactCopies() {
+
+		String qry = "{ \"name\" : \"Thomas\"}";
+		String fields = "{\"name\":1, \"age\":1}";
+
+		BasicQuery query1 = new BasicQuery(qry, fields);
+		query1.setSortObject(new BasicDBObject("name", -1));
+
+		BasicQuery query2 = new BasicQuery(qry, fields);
+		query2.setSortObject(new BasicDBObject("name", -1));
+
+		assertThat(query1, is(equalTo(query1)));
+		assertThat(query1, is(equalTo(query2)));
+		assertThat(query1.hashCode(), is(query2.hashCode()));
+	}
+
+	/**
+	 * @see DATAMONGO-1093
+	 */
+	@Test
+	public void handlesEqualsAndHashCodeCorrectlyWhenBasicQuerySettingsDiffer() {
+
+		String qry = "{ \"name\" : \"Thomas\"}";
+		String fields = "{\"name\":1, \"age\":1}";
+
+		BasicQuery query1 = new BasicQuery(qry, fields);
+		query1.setSortObject(new BasicDBObject("name", -1));
+
+		BasicQuery query2 = new BasicQuery(qry, fields);
+		query2.setSortObject(new BasicDBObject("name", 1));
+
+		assertThat(query1, is(not(equalTo(query2))));
+		assertThat(query1.hashCode(), is(not(query2.hashCode())));
+	}
+
+	/**
+	 * @see DATAMONGO-1093
+	 */
+	@Test
+	public void handlesEqualsAndHashCodeCorrectlyWhenQuerySettingsDiffer() {
+
+		String qry = "{ \"name\" : \"Thomas\"}";
+		String fields = "{\"name\":1, \"age\":1}";
+
+		BasicQuery query1 = new BasicQuery(qry, fields);
+		query1.getMeta().setComment("foo");
+
+		BasicQuery query2 = new BasicQuery(qry, fields);
+		query2.getMeta().setComment("bar");
+
+		assertThat(query1, is(not(equalTo(query2))));
+		assertThat(query1.hashCode(), is(not(query2.hashCode())));
+	}
 }