Add interface classification

typesystem/src/main/java/org/apache/hadoop/metadata/classification/InterfaceAudience.java

+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.metadata.classification;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * Annotation to mark methods for consumption.
+ */
+@InterfaceAudience.Public
+public class InterfaceAudience {
+    private InterfaceAudience() {
+    }
+
+    @Documented
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface Private {
+    }
+
+    @Documented
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface LimitedPrivate {
+        String[] value();
+    }
+
+    @Documented
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface Public {
+    }
+}

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/Referenceable.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.metadata.typesystem;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import org.apache.hadoop.metadata.classification.InterfaceAudience;
 import org.apache.hadoop.metadata.typesystem.persistence.Id;
 
 import java.util.List;
@@ -60,11 +61,12 @@ public class Referenceable extends Struct implements IReferenceableInstance {
     }
 
     /**
-     * @nopublic only use during deserialization
+     * Not public - only use during deserialization
      * @param guid
      * @param typeName
      * @param values
      */
+    @InterfaceAudience.Private
     public Referenceable(String guid, String typeName, Map<String, Object> values,
                          List<String> _traitNames,
                          Map<String, IStruct> _traits) {

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/Struct.java

@@ -18,6 +18,8 @@
 
 package org.apache.hadoop.metadata.typesystem;
 
+import org.apache.hadoop.metadata.classification.InterfaceAudience;
+
 import java.util.HashMap;
 import java.util.Map;
 
@@ -28,12 +30,10 @@ public class Struct implements IStruct {
 
     public Struct(String typeName) {
         this.typeName = typeName;
-        values = new HashMap<String, Object>();
+        values = new HashMap<>();
     }
 
-    /**
-     @nopublic
-     */
+    @InterfaceAudience.Private
     public Struct(String typeName, Map<String, Object> values) {
         this(typeName);
         this.values.putAll(values);
@@ -54,10 +54,7 @@ public class Struct implements IStruct {
         values.put(attrName, value);
     }
 
-    /**
-     * @nopublic
-     * @return
-     */
+    @InterfaceAudience.Private
     public Map<String, Object> getValuesMap() {
         return values;
     }

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/types/AttributeDefinition.java

@@ -18,6 +18,8 @@
 
 package org.apache.hadoop.metadata.typesystem.types;
 
+import com.google.common.base.Preconditions;
+
 public final class AttributeDefinition {
 
     public final String name;
@@ -42,6 +44,9 @@ public final class AttributeDefinition {
     public AttributeDefinition(String name, String dataTypeName,
                                Multiplicity multiplicity, boolean isComposite, boolean isUnique,
                                boolean isIndexable, String reverseAttributeName) {
+        Preconditions.checkNotNull(name);
+        Preconditions.checkNotNull(dataTypeName);
+
         this.name = name;
         this.dataTypeName = dataTypeName;
         this.multiplicity = multiplicity;
@@ -64,9 +69,9 @@ public final class AttributeDefinition {
         if (!dataTypeName.equals(that.dataTypeName)) return false;
         if (!multiplicity.equals(that.multiplicity)) return false;
         if (!name.equals(that.name)) return false;
-        if (reverseAttributeName != null ? !reverseAttributeName.equals(that.reverseAttributeName)
-                : that
-                        .reverseAttributeName != null)
+        if (reverseAttributeName != null
+                ? !reverseAttributeName.equals(that.reverseAttributeName)
+                : that.reverseAttributeName != null)
             return false;
 
         return true;

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/types/HierarchicalTypeDefinition.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.metadata.typesystem.types;
 
 import com.google.common.collect.ImmutableList;
+import org.apache.hadoop.metadata.classification.InterfaceAudience;
 
 public class HierarchicalTypeDefinition<T extends HierarchicalType> extends StructTypeDefinition {
 
@@ -26,14 +27,15 @@ public class HierarchicalTypeDefinition<T extends HierarchicalType> extends Stru
     public final String hierarchicalMetaTypeName;
 
     /**
-     * Used for json deserialization only
-     * @nopublic
+     * Used for json deserialization only.
+     * not intended public consumption
      * @param hierarchicalMetaTypeName
      * @param typeName
      * @param superTypes
      * @param attributeDefinitions
      * @throws ClassNotFoundException
      */
+    @InterfaceAudience.Private
     public HierarchicalTypeDefinition(String hierarchicalMetaTypeName,
                                       String typeName, String[] superTypes,
                                       AttributeDefinition[] attributeDefinitions)

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/types/TypeSystem.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.metadata.typesystem.types;
 
 import com.google.common.collect.ImmutableList;
 import org.apache.hadoop.metadata.MetadataException;
+import org.apache.hadoop.metadata.classification.InterfaceAudience;
 import org.apache.hadoop.metadata.typesystem.TypesDef;
 
 import javax.inject.Singleton;
@@ -37,6 +38,7 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 @Singleton
+@InterfaceAudience.Private
 public class TypeSystem {
     private static final TypeSystem INSTANCE = new TypeSystem();
     public static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
@@ -59,9 +61,9 @@ public class TypeSystem {
     }
 
     /**
-     * This is only used for testing prurposes.
-     * @nonpublic
+     * This is only used for testing purposes. Not intended for public use.
      */
+    @InterfaceAudience.Private
     public void reset() {
         initialize();
     }

typesystem/src/main/java/org/apache/hadoop/metadata/typesystem/types/utils/TypesUtil.java

@@ -47,6 +47,11 @@ public class TypesUtil {
         return new AttributeDefinition(name, dataType, Multiplicity.OPTIONAL, false, null);
     }
 
+    public static AttributeDefinition createRequiredAttrDef(String name,
+                                                            String dataType) {
+        return new AttributeDefinition(name, dataType, Multiplicity.REQUIRED, false, null);
+    }
+
     public static AttributeDefinition createUniqueRequiredAttrDef(String name,
                                                                   IDataType dataType) {
         return new AttributeDefinition(name, dataType.getName(),