Refactor classes to be either final or have final equals/hashCode

Author: mziccard

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/BigQueryError.java

@@ -17,7 +17,7 @@
  * {@link BigQueryException} is thrown the BigQuery Error that caused it, if any, can be accessed
  * with {@link BigQueryException#error()}.
  */
-public class BigQueryError implements Serializable {
+public final class BigQueryError implements Serializable {
 
   static final Function<ErrorProto, BigQueryError> FROM_PB_FUNCTION =
       new Function<ErrorProto, BigQueryError>() {
@@ -98,7 +98,9 @@ public String toString() {
 
   @Override
   public boolean equals(Object obj) {
-    return obj instanceof BigQueryError && Objects.equals(toPb(), ((BigQueryError) obj).toPb());
+    return obj == this
+        || obj instanceof BigQueryError
+        && Objects.equals(toPb(), ((BigQueryError) obj).toPb());
   }
 
   ErrorProto toPb() {

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/CopyJobConfiguration.java

@@ -181,8 +181,9 @@ ToStringHelper toStringHelper() {
 
   @Override
   public final boolean equals(Object obj) {
-    return this == obj
-        || obj instanceof CopyJobConfiguration
+    return obj == this
+        || obj != null
+        && obj.getClass().equals(CopyJobConfiguration.class)
         && baseEquals((CopyJobConfiguration) obj);
   }
 

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/CsvOptions.java

@@ -25,7 +25,7 @@
  * Google BigQuery options for CSV format. This class wraps some properties of CSV files used by
  * BigQuery to parse external data.
  */
-public class CsvOptions extends FormatOptions {
+public final class CsvOptions extends FormatOptions {
 
   private static final long serialVersionUID = 2193570529308612708L;
 
@@ -224,7 +224,9 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object obj) {
-    return obj instanceof CsvOptions && Objects.equals(toPb(), ((CsvOptions) obj).toPb());
+    return obj == this
+        || obj instanceof CsvOptions
+        && Objects.equals(toPb(), ((CsvOptions) obj).toPb());
   }
 
   com.google.api.services.bigquery.model.CsvOptions toPb() {

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/Dataset.java

@@ -231,10 +231,15 @@ public Builder toBuilder() {
 
   @Override
   public final boolean equals(Object obj) {
-    return this == obj
-        || obj instanceof Dataset
-        && Objects.equals(toPb(), ((Dataset) obj).toPb())
-        && Objects.equals(options, ((Dataset) obj).options);
+    if (obj == this) {
+      return true;
+    }
+    if (obj == null || !obj.getClass().equals(Dataset.class)) {
+      return false;
+    }
+    Dataset other = (Dataset) obj;
+    return Objects.equals(toPb(), other.toPb())
+        && Objects.equals(options, other.options);
   }
 
   @Override

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/DatasetId.java

@@ -26,7 +26,7 @@
 /**
  * Google BigQuery Dataset identity.
  */
-public class DatasetId implements Serializable {
+public final class DatasetId implements Serializable {
 
   private static final long serialVersionUID = -6186254820908152300L;
 
@@ -68,7 +68,9 @@ public static DatasetId of(String dataset) {
 
   @Override
   public boolean equals(Object obj) {
-    return obj instanceof DatasetId && Objects.equals(toPb(), ((DatasetId) obj).toPb());
+    return obj == this
+        || obj instanceof DatasetId
+        && Objects.equals(toPb(), ((DatasetId) obj).toPb());
   }
 
   @Override

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/DatasetInfo.java

@@ -395,7 +395,8 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object obj) {
-    return obj != null
+    return obj == this
+        || obj != null
         && obj.getClass().equals(DatasetInfo.class)
         && Objects.equals(toPb(), ((DatasetInfo) obj).toPb());
   }

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/ExternalTableDefinition.java

@@ -256,8 +256,9 @@ ToStringHelper toStringHelper() {
 
   @Override
   public final boolean equals(Object obj) {
-    return this == obj
-        || obj instanceof ExternalTableDefinition
+    return obj == this
+        || obj != null
+        && obj.getClass().equals(ExternalTableDefinition.class)
         && baseEquals((ExternalTableDefinition) obj);
   }
 

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/ExtractJobConfiguration.java

@@ -211,8 +211,9 @@ ToStringHelper toStringHelper() {
 
   @Override
   public final boolean equals(Object obj) {
-    return this == obj
-        || obj instanceof ExtractJobConfiguration
+    return obj == this
+        || obj != null
+        && obj.getClass().equals(ExtractJobConfiguration.class)
         && baseEquals((ExtractJobConfiguration) obj);
   }
 

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/Field.java

@@ -32,12 +32,12 @@
 import java.util.Objects;
 
 /**
- * Google BigQuery Table field. A table field has a name, a value, a mode and possibly a
- * description. Supported types are: {@link Type#integer()}, {@link Type#bool()},
- * {@link Type#string()}, {@link Type#floatingPoint()}, {@link Type#timestamp()} and
- * {@link Type#record(Field...)}. One or more fields form a table's schema.
+ * Google BigQuery Table field. A table field has a name, a type, a mode and possibly a description.
+ * Supported types are: {@link Type#integer()}, {@link Type#bool()}, {@link Type#string()},
+ * {@link Type#floatingPoint()}, {@link Type#timestamp()} and {@link Type#record(Field...)}. One or
+ * more fields form a table's schema.
  */
-public class Field implements Serializable {
+public final class Field implements Serializable {
 
   static final Function<TableFieldSchema, Field> FROM_PB_FUNCTION =
       new Function<TableFieldSchema, Field>() {
@@ -56,6 +56,11 @@ public TableFieldSchema apply(Field field) {
 
   private static final long serialVersionUID = -8154262932305199256L;
 
+  private final String name;
+  private final Type type;
+  private final String mode;
+  private final String description;
+
   /**
    * Data Types for a BigQuery Table field. This class provides factory methods for all BigQuery
    * field types. To instantiate a RECORD value the list of sub-fields must be provided.
@@ -185,11 +190,6 @@ public enum Mode {
     NULLABLE, REQUIRED, REPEATED
   }
 
-  private final String name;
-  private final Type type;
-  private final String mode;
-  private final String description;
-
   public static final class Builder {
 
     private String name;

gcloud-java-bigquery/src/main/java/com/google/gcloud/bigquery/FieldValue.java

@@ -216,13 +216,16 @@ public String toString() {
   }
 
   @Override
-  public int hashCode() {
+  public final int hashCode() {
     return Objects.hash(attribute, value);
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (!(obj instanceof FieldValue)) {
+  public final boolean equals(Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (obj == null || !obj.getClass().equals(FieldValue.class)) {
       return false;
     }
     FieldValue other = (FieldValue) obj;