JRef+JsonPointer implementation as ObjectMapper module. #5920

src/test/java/module-info.java

@@ -82,6 +82,7 @@
     opens tools.jackson.databind.ext.xml;
     opens tools.jackson.databind.format;
     opens tools.jackson.databind.interop;
+    opens tools.jackson.databind.jref;
     opens tools.jackson.databind.jsonschema;
     opens tools.jackson.databind.jsontype.deduct;
     opens tools.jackson.databind.jsontype.deftyping;

src/test/java/tools/jackson/databind/jref/JRefAbstractTest.java

@@ -0,0 +1,44 @@
+package tools.jackson.databind.jref;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.regex.Pattern;
+
+import tools.jackson.databind.JRefModule;
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
+
+public class JRefAbstractTest {
+
+    public static boolean TRACE = false;
+
+    public static JsonMapper.Builder jsonMapperBuilder() {
+        return JsonMapper.builder();
+    }
+
+    protected ObjectMapper buildObjectMapperJRef() {
+        return jsonMapperBuilder().addModule(new JRefModule()).build();
+    }
+
+    protected ObjectMapper buildObjectMapperNoJRef() {
+        return jsonMapperBuilder().build();
+    }
+
+    static long countMatches(String text, String target) {
+        if (text == null || target == null || target.isEmpty())
+            return 0;
+        String quotedTarget = Pattern.quote(target);
+
+        return Pattern.compile(quotedTarget).matcher(text).results().count();
+    }
+
+    protected void assertJRefCount(String input, long expectedJRefs) {
+        assertEquals(expectedJRefs, countMatches(input, "$ref"));
+    }
+
+    void trace(String method, String s) {
+        if (TRACE) {
+            System.out.println(method + "." + s);
+        }
+    }
+}

src/test/java/tools/jackson/databind/jref/JRefArrayTest.java

@@ -0,0 +1,196 @@
+package tools.jackson.databind.jref;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Map;
+
+import tools.jackson.databind.ObjectMapper;
+
+import org.junit.jupiter.api.Test;
+
+public class JRefArrayTest extends JRefAbstractTest {
+
+    @Test
+    void testObjectArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Object o1 = new Object();
+        Object o2 = o1;
+        Object[] arr = new Object[] { o1, o2 };
+        String out = mapper.writeValueAsString(arr);
+        assertJRefCount(out, 1);
+        trace("testObjectArrayRef jrefserialized=", out);
+        Object[] oa = mapper.readValue(out, Object[].class);
+        assertTrue(oa[0] instanceof Map);
+        assertTrue(oa[1] instanceof Map);
+        assertEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void testStringArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        String o1 = new String("one");
+        String o2 = o1;
+        String[] arr = new String[] { o1, o2 };
+        String out = mapper.writeValueAsString(arr);
+        assertJRefCount(out, 1);
+        trace("testStringArrayRef jrefserialized=", out);
+        String[] oa = mapper.readValue(out, String[].class);
+        assertTrue(oa[0] instanceof String);
+        assertTrue(oa[1] instanceof String);
+        assertEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void test2DObjectArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Object o1 = new Object();
+        Object o2 = o1;
+        Object[] arr1 = new Object[] { o1, o2 };
+        Object[] arr2 = arr1;
+        String out = mapper.writeValueAsString(new Object[][] { arr1, arr2 });
+        assertJRefCount(out, 2);
+        trace("test2DObjectArrayRef jrefserialized=", out);
+        Object[][] oa = mapper.readValue(out, Object[][].class);
+        assertTrue(oa[0][0] instanceof Map);
+        assertTrue(oa[0][1] instanceof Map);
+        assertEquals(oa[0], oa[1]);
+        assertArrayEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void test2DStringArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        String o1 = new String("one");
+        String o2 = o1;
+        String[] arr1 = new String[] { o1, o2 };
+        String[] arr2 = arr1;
+        String out = mapper.writeValueAsString(new String[][] { arr1, arr2 });
+        assertJRefCount(out, 2);
+        trace("test2DStringArrayRef jrefserialized=", out);
+        String[][] oa = mapper.readValue(out, String[][].class);
+        assertTrue(oa[0][0] instanceof String);
+        assertTrue(oa[0][1] instanceof String);
+        assertEquals(oa[0], oa[1]);
+        assertArrayEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void testIntegerArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Integer o1 = Integer.valueOf(100);
+        Integer o2 = o1;
+        Integer[] arr = new Integer[] { o1, o2 };
+        String out = mapper.writeValueAsString(arr);
+        assertJRefCount(out, 1);
+        trace("testIntegerArrayRef jrefserialized=", out);
+        Integer[] oa = mapper.readValue(out, Integer[].class);
+        assertTrue(oa[0] instanceof Integer);
+        assertTrue(oa[1] instanceof Integer);
+        assertEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void test2DIntegerArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Integer o1 = Integer.valueOf(5);
+        Integer o2 = o1;
+        Integer[] arr1 = new Integer[] { o1, o2 };
+        Integer[] arr2 = arr1;
+        String out = mapper.writeValueAsString(new Integer[][] { arr1, arr2 });
+        assertJRefCount(out, 2);
+        trace("test2DStringArrayRef jrefserialized=", out);
+        Integer[][] oa = mapper.readValue(out, Integer[][].class);
+        assertTrue(oa[0][0] instanceof Integer);
+        assertTrue(oa[0][1] instanceof Integer);
+        assertEquals(oa[0], oa[1]);
+        assertArrayEquals(oa[0], oa[1]);
+    }
+
+    @Test
+    void test3DObjectArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Object o1 = new Object();
+        Object o2 = o1;
+        Object[] arr1 = new Object[] { o1, o2 };
+        Object[][] arr2d = new Object[][] { arr1, arr1 };
+        Object[][][] arr3d = new Object[][][] { arr2d, arr2d };
+
+        String out = mapper.writeValueAsString(arr3d);
+        assertJRefCount(out, 3);
+        trace("test3DObjectArrayRef jrefserialized=", out);
+
+        Object[][][] oa = mapper.readValue(out, Object[][][].class);
+        assertEquals(oa[0], oa[1]);
+        assertEquals(oa[0][0], oa[0][1]);
+        assertEquals(oa[0][0][0], oa[0][0][1]);
+        assertTrue(oa[0][0][0] instanceof Map);
+    }
+
+    @Test
+    void test3DStringArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        String s1 = new String("test");
+        String[] arr1 = new String[] { s1, s1 };
+        String[][] arr2d = new String[][] { arr1, arr1 };
+        String[][][] arr3d = new String[][][] { arr2d, arr2d };
+
+        String out = mapper.writeValueAsString(arr3d);
+        assertJRefCount(out, 3);
+        trace("test3DStringArrayRef jrefserialized=", out);
+
+        String[][][] oa = mapper.readValue(out, String[][][].class);
+        assertArrayEquals(oa[0], oa[1]);
+        assertArrayEquals(oa[0][0], oa[0][1]);
+        assertEquals(oa[0][0][0], oa[0][0][1]);
+        assertTrue(oa[0][0][0] instanceof String);
+    }
+
+    @Test
+    void test4DObjectArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        Object o1 = new Object();
+        Object[] arr1 = new Object[] { o1 };
+        Object[][] arr2 = new Object[][] { arr1 };
+        Object[][][] arr3 = new Object[][][] { arr2 };
+        Object[][][][] arr4 = new Object[][][][] { arr3, arr3 };
+
+        String out = mapper.writeValueAsString(arr4);
+        assertJRefCount(out, 1);
+        trace("test4DObjectArrayRef jrefserialized=", out);
+
+        Object[][][][] oa = mapper.readValue(out, Object[][][][].class);
+        assertEquals(oa[0], oa[1]);
+        assertEquals(oa[0][0], oa[1][0]);
+        assertEquals(oa[0][0][0], oa[1][0][0]);
+        assertTrue(oa[0][0][0][0] instanceof Map);
+    }
+
+    @Test
+    void test4DStringArrayRef() throws Exception {
+        ObjectMapper mapper = buildObjectMapperJRef();
+        String s1 = new String("deep");
+        String s2 = new String("thoughts");
+        String[] arr1 = new String[] { s1, s2, s2 };
+        String[] arr1a = arr1;
+        String[][] arr2 = new String[][] { arr1, arr1a };
+        String[][] arr2a = arr2;
+        String[][][] arr3 = new String[][][] { arr2, arr2a };
+        String[][][] arr3a = arr3;
+        String[][][][] arr4 = new String[][][][] { arr3, arr3a, arr3 };
+
+        String out = mapper.writeValueAsString(arr4);
+        assertJRefCount(out, 5);
+        trace("test4DStringArrayRef jrefserialized=", out);
+
+        String[][][][] oa = mapper.readValue(out, String[][][][].class);
+        assertArrayEquals(oa[0], oa[1]);
+        assertArrayEquals(oa[0], oa[2]);
+        assertArrayEquals(oa[0][0], oa[0][1]);
+        assertArrayEquals(oa[0][0][0], oa[0][0][1]);
+        assertEquals(oa[0][0][0][0], "deep");
+        assertEquals(oa[0][0][0][1], "thoughts");
+
+    }
+}