JAVA-2656: Deprecate MongoClientSettings methods that take or return a list of credentials, and add otherwise equivalent methods that take or return a single credential

Author: jyemin

driver-async/src/main/com/mongodb/async/client/MongoClientSettings.java

@@ -37,8 +37,10 @@
 import java.util.Collections;
 import java.util.List;
 
+import static com.mongodb.assertions.Assertions.isTrue;
 import static com.mongodb.assertions.Assertions.isTrueArgument;
 import static com.mongodb.assertions.Assertions.notNull;
+import static java.util.Collections.singletonList;
 
 
 /**
@@ -272,12 +274,27 @@ public Builder readConcern(final ReadConcern readConcern) {
          * @param credentialList the credential list
          * @return {@code this}
          * @see MongoClientSettings#getCredentialList()
+         * @deprecated Prefer {@link #credential(MongoCredential)}
          */
+        @Deprecated
         public Builder credentialList(final List<MongoCredential> credentialList) {
             this.credentialList = Collections.unmodifiableList(notNull("credentialList", credentialList));
             return this;
         }
 
+        /**
+         * Sets the credential.
+         *
+         * @param credential the credential
+         * @return {@code this}
+         * @see MongoClientSettings#getCredentialList()
+         * @since 3.6
+         */
+        public Builder credential(final MongoCredential credential) {
+            this.credentialList = singletonList(notNull("credential", credential));
+            return this;
+        }
+
         /**
          * Sets the codec registry
          *
@@ -379,11 +396,24 @@ public ReadPreference getReadPreference() {
      * Gets the credential list.
      *
      * @return the credential list
+     * @deprecated Prefer {@link #getCredential()}
      */
+    @Deprecated
     public List<MongoCredential> getCredentialList() {
         return credentialList;
     }
 
+    /**
+     * Gets the credential list.
+     *
+     * @return the credential list
+     * @since 3.6
+     */
+    public MongoCredential getCredential() {
+        isTrue("Single or no credential", credentialList.size() <= 1);
+        return credentialList.isEmpty() ? null : credentialList.get(0);
+    }
+
     /**
      * The write concern to use.
      *

driver-async/src/test/unit/com/mongodb/async/client/MongoClientSettingsSpecification.groovy

@@ -54,6 +54,8 @@ class MongoClientSettingsSpecification extends Specification {
         options.serverSettings == ServerSettings.builder().build()
         options.streamFactoryFactory == null
         options.compressorList == []
+        options.credentialList == []
+        options.credential == null
     }
 
     @SuppressWarnings('UnnecessaryObjectReferences')
@@ -101,6 +103,11 @@ class MongoClientSettingsSpecification extends Specification {
         then:
         thrown(IllegalArgumentException)
 
+        when:
+        builder.credential(null)
+        then:
+        thrown(IllegalArgumentException)
+
         when:
         builder.credentialList(null)
         then:
@@ -140,6 +147,7 @@ class MongoClientSettingsSpecification extends Specification {
         def commandListener = Stub(CommandListener)
         def clusterSettings = ClusterSettings.builder().hosts([new ServerAddress('localhost')]).requiredReplicaSetName('test').build()
 
+        when:
         def options = MongoClientSettings.builder()
                 .readPreference(ReadPreference.secondary())
                 .writeConcern(WriteConcern.JOURNALED)
@@ -159,7 +167,7 @@ class MongoClientSettingsSpecification extends Specification {
                 .compressorList([MongoCompressor.createZlibCompressor()])
                 .build()
 
-        expect:
+        then:
         options.getReadPreference() == ReadPreference.secondary()
         options.getWriteConcern() == WriteConcern.JOURNALED
         options.getRetryWrites()
@@ -172,10 +180,20 @@ class MongoClientSettingsSpecification extends Specification {
         options.serverSettings == serverSettings
         options.codecRegistry == codecRegistry
         options.credentialList == credentialList
+        options.credential == credentialList.get(0)
         options.connectionPoolSettings == connectionPoolSettings
         options.clusterSettings == clusterSettings
         options.streamFactoryFactory == streamFactoryFactory
         options.compressorList == [MongoCompressor.createZlibCompressor()]
+
+        when:
+        options = MongoClientSettings.builder()
+                .credential(credentialList.get(0))
+                .build()
+
+        then:
+        options.credentialList == credentialList
+        options.credential == credentialList.get(0)
     }
 
     def 'should be easy to create new options from existing'() {