Add StandardCoderObject to hide GSON internals

Added StandardCoderObject to hide GSON's JsonElement so that classes
are not dependent on the use of JsonElement, making it easier to switch
out serialization mechanisms in the future.

Added a test for field-not-found.
Converted tabs to spaces in json test file.

Simplified StandardCoderObject and added methods to Coder for
translating to and from StandardCoderObject.

Removed a test for a method that no longer exists.
Added more tests to a test case.

Change-Id: I5123dc3f17c940ded431ef7f9ccd8c4bff6b1c5f
Issue-ID: POLICY-1444
Signed-off-by: Jim Hahn <jrh3@att.com>

2 files changed, 137 insertions, 0 deletions

diff --git a/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderObjectTest.java b/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderObjectTest.java
new file mode 100644
index 00000000..44086f30
--- /dev/null
+++ b/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderObjectTest.java
@@ -0,0 +1,89 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.utils.coder;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import org.junit.Before;
+import org.junit.Test;
+
+public class StandardCoderObjectTest {
+    private static final Gson gson = new Gson();
+
+    private static final String PROP1 = "abc";
+    private static final String PROP2 = "ghi";
+    private static final String PROP2b = "jkl";
+    private static final String VAL1 = "def";
+    private static final String VAL2 = "mno";
+    private static final String JSON = "{'abc':'def','ghi':{'jkl':'mno'}}".replace('\'', '"');
+
+    private StandardCoderObject sco;
+
+    /**
+     * Creates a standard object, populated with some data.
+     *
+     * @throws Exception if an error occurs
+     */
+    @Before
+    public void setUp() throws Exception {
+        sco = new StandardCoderObject(gson.fromJson(JSON, JsonElement.class));
+    }
+
+    @Test
+    public void testStandardCoderObject() {
+        assertNull(new StandardCoderObject().getData());
+    }
+
+    @Test
+    public void testStandardCoderObjectJsonElement() {
+        assertNotNull(sco.getData());
+        assertEquals(JSON, gson.toJson(sco.getData()));
+    }
+
+    @Test
+    public void testGetString() throws Exception {
+        // one field
+        assertEquals(VAL1, sco.getString(PROP1));
+
+        // multiple fields
+        assertEquals(VAL2, sco.getString(PROP2, PROP2b));
+
+        // not found
+        assertNull(sco.getString("xyz"));
+
+        // read from null object
+        assertNull(new StandardCoderObject().getString());
+        assertNull(new StandardCoderObject().getString(PROP1));
+
+        JsonElement obj = gson.fromJson("{'abc':[]}".replace('\'', '"'), JsonElement.class);
+        sco = new StandardCoderObject(obj);
+
+        // not a primitive
+        assertNull(sco.getString(PROP1));
+
+        // not a JSON object
+        assertNull(sco.getString(PROP1, PROP2));
+    }
+}
diff --git a/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderTest.java b/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderTest.java
index 25cce748..7583d776 100644
--- a/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderTest.java
+++ b/utils/src/test/java/org/onap/policy/common/utils/coder/StandardCoderTest.java
@@ -22,6 +22,7 @@ package org.onap.policy.common.utils.coder;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
@@ -196,4 +197,51 @@ public class StandardCoderTest {
         assertThatThrownBy(() -> coder.decode(file, JsonElement.class)).isInstanceOf(CoderException.class)
                         .hasCause(ioe);
     }
+
+    @Test
+    public void testToStandard() throws Exception {
+        MyObject obj = new MyObject();
+        obj.abc = "xyz";
+        StandardCoderObject sco = coder.toStandard(obj);
+        assertNotNull(sco.getData());
+        assertEquals("{'abc':'xyz'}".replace('\'', '"'), sco.getData().toString());
+
+        // class instead of object -> exception
+        assertThatThrownBy(() -> coder.toStandard(String.class)).isInstanceOf(CoderException.class);
+    }
+
+    @Test
+    public void testFromStandard() throws Exception {
+        MyObject obj = new MyObject();
+        obj.abc = "pdq";
+        StandardCoderObject sco = coder.toStandard(obj);
+
+        MyObject obj2 = coder.fromStandard(sco, MyObject.class);
+        assertEquals(obj.toString(), obj2.toString());
+
+        // null class -> exception
+        assertThatThrownBy(() -> coder.fromStandard(sco, null)).isInstanceOf(CoderException.class);
+    }
+
+    @Test
+    public void testStandardTypeAdapter() throws Exception {
+        String json = "{'abc':'def'}".replace('\'', '"');
+        StandardCoderObject sco = coder.fromJson(json, StandardCoderObject.class);
+        assertNotNull(sco.getData());
+        assertEquals(json, sco.getData().toString());
+        assertEquals(json, coder.toJson(sco));
+
+        // invalid json -> exception
+        assertThatThrownBy(() -> coder.fromJson(new StringReader("["), StandardCoderObject.class));
+    }
+
+
+    private static class MyObject {
+        private String abc;
+
+        @Override
+        public String toString() {
+            return "MyObject [abc=" + abc + "]";
+        }
+    }
 }