add helpers for trait ser/de

typesystem/src/main/scala/org/apache/hadoop/metadata/typesystem/json/Serialization.scala

@@ -19,7 +19,7 @@
 package org.apache.hadoop.metadata.typesystem.json
 
 import org.apache.hadoop.metadata.typesystem._
-import org.apache.hadoop.metadata.typesystem.persistence.{Id, ReferenceableInstance}
+import org.apache.hadoop.metadata.typesystem.persistence.{StructInstance, Id, ReferenceableInstance}
 import org.apache.hadoop.metadata.typesystem.types.DataTypes.{ArrayType, MapType, TypeCategory}
 import org.apache.hadoop.metadata.typesystem.types._
 import org.json4s.JsonAST.JInt
@@ -271,6 +271,13 @@ object Serialization {
         write(value)
     }
 
+    def toJson(value: ITypedInstance): String = {
+      implicit val formats = org.json4s.native.Serialization.formats(NoTypeHints) + new TypedStructSerializer +
+        new TypedReferenceableInstanceSerializer + new BigDecimalSerializer + new BigIntegerSerializer
+
+      write(value)
+    }
+
     def toJsonPretty(value: ITypedReferenceableInstance): String = {
         implicit val formats = org.json4s.native.Serialization.formats(NoTypeHints) + new TypedStructSerializer +
             new TypedReferenceableInstanceSerializer + new BigDecimalSerializer + new BigIntegerSerializer
@@ -284,4 +291,11 @@ object Serialization {
 
         read[ReferenceableInstance](jsonStr)
     }
+
+  def traitFromJson(jsonStr: String): ITypedInstance = {
+    implicit val formats = org.json4s.native.Serialization.formats(NoTypeHints) + new TypedStructSerializer +
+      new TypedReferenceableInstanceSerializer + new BigDecimalSerializer + new BigIntegerSerializer
+
+    read[StructInstance](jsonStr)
+  }
 }

typesystem/src/test/java/org/apache/hadoop/metadata/typesystem/json/SerializationJavaTest.java

@@ -21,8 +21,7 @@ package org.apache.hadoop.metadata.typesystem.json;
 import com.google.common.collect.ImmutableList;
 import org.apache.hadoop.metadata.BaseTest;
 import org.apache.hadoop.metadata.MetadataException;
-import org.apache.hadoop.metadata.typesystem.ITypedReferenceableInstance;
-import org.apache.hadoop.metadata.typesystem.Referenceable;
+import org.apache.hadoop.metadata.typesystem.*;
 import org.apache.hadoop.metadata.typesystem.types.AttributeDefinition;
 import org.apache.hadoop.metadata.typesystem.types.ClassType;
 import org.apache.hadoop.metadata.typesystem.types.DataTypes;
@@ -148,4 +147,28 @@ public class SerializationJavaTest extends BaseTest {
         Assert.assertEquals(hrDept2.toString(), hrDeptStr);
 
     }
+
+    @Test
+    public void testTrait() throws MetadataException {
+
+        TypeSystem ts = getTypeSystem();
+        HierarchicalTypeDefinition<TraitType> securityClearanceTypeDef = createTraitTypeDef(
+                "SecurityClearance2",
+                ImmutableList.<String>of(),
+                createRequiredAttrDef("level", DataTypes.INT_TYPE)
+        );
+
+        ts.defineTypes(ImmutableList.<StructTypeDefinition>of(),
+                ImmutableList.<HierarchicalTypeDefinition<TraitType>>of(securityClearanceTypeDef),
+                ImmutableList.<HierarchicalTypeDefinition<ClassType>>of());
+
+
+        Struct s = new Struct("SecurityClearance2");
+        s.set("level", 1);
+        TraitType tType = ts.getDataType(TraitType.class, "SecurityClearance2");
+        ITypedInstance t = tType.convert(s, Multiplicity.REQUIRED);
+        String jsonStr = Serialization$.MODULE$.toJson(t);
+        ITypedInstance t2 = Serialization$.MODULE$.traitFromJson(jsonStr);
+        Assert.assertEquals(t.toString(), t2.toString());
+    }
 }
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