@@ -30,8 +30,8 @@ public final class BackupId {
 private final String backup;
 
 BackupId(InstanceId instanceId, String backup) {
-this.instanceId = instanceId;
-this.backup = backup;
+this.instanceId = Preconditions.checkNotNull(instanceId);
+this.backup = Preconditions.checkNotNull(backup);
 }
 
 /** Returns the instance id for this backup. */
@@ -81,6 +81,7 @@ public String toString() {
 * @throws IllegalArgumentException if {@code name} does not conform to the expected pattern
 */
 static BackupId of(String name) {
+Preconditions.checkNotNull(name);
 Map<String, String> parts = NAME_TEMPLATE.match(name);
 Preconditions.checkArgument(
 parts != null, "Name should conform to pattern %s: %s", NAME_TEMPLATE, name);

@@ -31,8 +31,8 @@ public final class DatabaseId {
 private final String database;
 
 DatabaseId(InstanceId instanceId, String database) {
-this.instanceId = instanceId;
-this.database = database;
+this.instanceId = Preconditions.checkNotNull(instanceId);
+this.database = Preconditions.checkNotNull(database);
 }
 
 /** Returns the instance id for this databse. */
@@ -82,6 +82,7 @@ public String toString() {
 * @throws IllegalArgumentException if {@code name} does not conform to the expected pattern
 */
 static DatabaseId of(String name) {
+Preconditions.checkNotNull(name);
 Map<String, String> parts = NAME_TEMPLATE.match(name);
 Preconditions.checkArgument(
 parts != null, "Name should conform to pattern %s: %s", NAME_TEMPLATE, name);

@@ -30,8 +30,8 @@ public final class InstanceConfigId {
 private final String instanceConfig;
 
 InstanceConfigId(String project, String instanceConfig) {
-this.project = project;
-this.instanceConfig = instanceConfig;
+this.project = Preconditions.checkNotNull(project);
+this.instanceConfig = Preconditions.checkNotNull(instanceConfig);
 }
 
 /** Returns project of this instane config. */
@@ -80,6 +80,7 @@ public String toString() {
 * pattern.
 */
 static InstanceConfigId of(String name) {
+Preconditions.checkNotNull(name);
 Map<String, String> parts = NAME_TEMPLATE.match(name);
 Preconditions.checkArgument(
 parts != null, "Name should confirm to pattern %s: %s", NAME_TEMPLATE, name);

@@ -30,8 +30,8 @@ public final class InstanceId {
 private final String instance;
 
 InstanceId(String project, String instance) {
-this.project = project;
-this.instance = instance;
+this.project = Preconditions.checkNotNull(project);
+this.instance = Preconditions.checkNotNull(instance);
 }
 
 /** Returns the instance ID. */
@@ -79,6 +79,7 @@ public String toString() {
 * pattern.
 */
 static InstanceId of(String name) {
+Preconditions.checkNotNull(name);
 Map<String, String> parts = NAME_TEMPLATE.match(name);
 Preconditions.checkArgument(
 parts != null, "Name should conform to pattern %s: %s", NAME_TEMPLATE, name);

@@ -44,11 +44,12 @@ static class SessionId {
 private final String name;
 
 private SessionId(DatabaseId db, String name) {
-this.db = db;
-this.name = name;
+this.db = Preconditions.checkNotNull(db);
+this.name = Preconditions.checkNotNull(name);
 }
 
 static SessionId of(String name) {
+Preconditions.checkNotNull(name);
 Map<String, String> parts = NAME_TEMPLATE.match(name);
 Preconditions.checkArgument(
 parts != null, "Name should conform to pattern %s: %s", NAME_TEMPLATE, name);