[WIP][ONOS-3722] Augment TableModel with Annotations Mechanism

Change-Id: I815ce0b0fde254dd730153c34905d9454f019d9a
diff --git a/core/api/src/main/java/org/onosproject/ui/table/TableModel.java b/core/api/src/main/java/org/onosproject/ui/table/TableModel.java
index d0fccb6..bf5d95d 100644
--- a/core/api/src/main/java/org/onosproject/ui/table/TableModel.java
+++ b/core/api/src/main/java/org/onosproject/ui/table/TableModel.java
@@ -22,6 +22,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -57,7 +58,7 @@
     private final Map<String, CellComparator> comparators = new HashMap<>();
     private final Map<String, CellFormatter> formatters = new HashMap<>();
     private final List<Row> rows = new ArrayList<>();
-
+    private final Map<String, Annot> annotations = new HashMap<>();
 
     /**
      * Constructs a table (devoid of data) with the given column IDs.
@@ -124,6 +125,28 @@
     }
 
     /**
+     * Inserts a new annotation.
+     *
+     * @param key key of annotation
+     * @param value value of annotation
+     */
+    public void addAnnotation(String key, Object value) {
+        Annot annot = new Annot(key, value);
+        annotations.put(key, annot);
+    }
+
+    /**
+     * Returns the annotations in this table.
+     *
+     * @return annotations
+     */
+    public Collection<Annot> getAnnotations() {
+        Collection<Annot> annots = new ArrayList<>(annotations.size());
+        annotations.forEach((k, v) -> annots.add(v));
+        return annots;
+    }
+
+    /**
      * Sets a cell comparator for the specified column.
      *
      * @param columnId column identifier
@@ -233,6 +256,53 @@
     }
 
     /**
+     * Model of an annotation.
+     */
+    public class Annot {
+        private final String key;
+        private final Object value;
+
+        /**
+         * Constructs an annotation with the given key and value.
+         *
+         * @param key the key
+         * @param value the value
+         */
+        public Annot(String key, Object value) {
+            this.key = key;
+            this.value = value;
+        }
+
+        /**
+         * Returns the annotation's key.
+         *
+         * @return key
+         */
+        public String key() {
+            return key;
+        }
+
+        /**
+         * Returns the annotation's value.
+         *
+         * @return value
+         */
+        public Object value() {
+            return value;
+        }
+
+        /**
+         * Returns the value as a string.
+         * This default implementation uses the value's toString() method.
+         *
+         * @return the value as a string
+         */
+        public String valueAsString() {
+            return value.toString();
+        }
+    }
+
+    /**
      * Model of a row.
      */
     public class Row {
diff --git a/core/api/src/main/java/org/onosproject/ui/table/TableRequestHandler.java b/core/api/src/main/java/org/onosproject/ui/table/TableRequestHandler.java
index b8d4857..43700db 100644
--- a/core/api/src/main/java/org/onosproject/ui/table/TableRequestHandler.java
+++ b/core/api/src/main/java/org/onosproject/ui/table/TableRequestHandler.java
@@ -25,6 +25,8 @@
  */
 public abstract class TableRequestHandler extends RequestHandler {
 
+    private static final String ANNOTS = "annots";
+    private static final String NO_ROWS_MSG_KEY = "no_rows_msg";
     private final String respType;
     private final String nodeName;
 
@@ -53,8 +55,11 @@
         String sortDir = JsonUtils.string(payload, "sortDir", "asc");
         tm.sort(sortCol, TableModel.sortDir(sortDir));
 
+        addTableConfigAnnotations(tm);
+
         ObjectNode rootNode = MAPPER.createObjectNode();
-        rootNode.set(nodeName, TableUtils.generateArrayNode(tm));
+        rootNode.set(nodeName, TableUtils.generateRowArrayNode(tm));
+        rootNode.set(ANNOTS, TableUtils.generateAnnotObjectNode(tm));
         sendMessage(respType, 0, rootNode);
     }
 
@@ -72,6 +77,15 @@
     }
 
     /**
+     * Adds all annotations to table model.
+     *
+     * @param tm a table model
+     */
+    protected void addTableConfigAnnotations(TableModel tm) {
+        tm.addAnnotation(NO_ROWS_MSG_KEY, noRowsMessage());
+    }
+
+    /**
      * Returns the default column ID to be used when one is not supplied in
      * the payload as the column on which to sort.
      * <p>
@@ -92,6 +106,15 @@
     protected abstract String[] getColumnIds();
 
     /**
+     * Subclasses should return the message to display in the table when there
+     * are no rows to display. For example, a host table might return
+     * "No hosts found".
+     *
+     * @return the message
+     */
+    protected abstract String noRowsMessage();
+
+    /**
      * Subclasses should populate the table model by adding
      * {@link TableModel.Row rows}.
      * <pre>
@@ -108,4 +131,4 @@
      * @param payload request payload
      */
     protected abstract void populateTable(TableModel tm, ObjectNode payload);
-}
+}
\ No newline at end of file
diff --git a/core/api/src/main/java/org/onosproject/ui/table/TableUtils.java b/core/api/src/main/java/org/onosproject/ui/table/TableUtils.java
index eb2dff7..14c6743 100644
--- a/core/api/src/main/java/org/onosproject/ui/table/TableUtils.java
+++ b/core/api/src/main/java/org/onosproject/ui/table/TableUtils.java
@@ -32,12 +32,12 @@
     private TableUtils() { }
 
     /**
-     * Generates a JSON array node from a table model.
+     * Generates a JSON array node from the rows of the given table model.
      *
      * @param tm the table model
-     * @return the array node representation
+     * @return the array node representation of rows
      */
-    public static ArrayNode generateArrayNode(TableModel tm) {
+    public static ArrayNode generateRowArrayNode(TableModel tm) {
         ArrayNode array = MAPPER.createArrayNode();
         for (TableModel.Row r : tm.getRows()) {
             array.add(toJsonNode(r, tm));
@@ -45,6 +45,20 @@
         return array;
     }
 
+    /**
+     * Generates a JSON object node from the annotations of the given table model.
+     *
+     * @param tm the table model
+     * @return the object node representation of the annotations
+     */
+    public static ObjectNode generateAnnotObjectNode(TableModel tm) {
+        ObjectNode node = MAPPER.createObjectNode();
+        for (TableModel.Annot a : tm.getAnnotations()) {
+            node.put(a.key(), a.valueAsString());
+        }
+        return node;
+    }
+
     private static JsonNode toJsonNode(TableModel.Row row, TableModel tm) {
         ObjectNode result = MAPPER.createObjectNode();
         String[] keys = tm.getColumnIds();
diff --git a/core/api/src/test/java/org/onosproject/ui/table/TableModelTest.java b/core/api/src/test/java/org/onosproject/ui/table/TableModelTest.java
index 7524bcb..8c79a05 100644
--- a/core/api/src/test/java/org/onosproject/ui/table/TableModelTest.java
+++ b/core/api/src/test/java/org/onosproject/ui/table/TableModelTest.java
@@ -21,6 +21,8 @@
 import org.onosproject.ui.table.cell.DefaultCellFormatter;
 import org.onosproject.ui.table.cell.HexFormatter;
 
+import java.util.Collection;
+
 import static org.junit.Assert.*;
 
 /**
@@ -122,7 +124,6 @@
         assertEquals("bad cell", true, row.get(BAR));
     }
 
-
     private static final String ONE = "one";
     private static final String TWO = "two";
     private static final String THREE = "three";
@@ -313,7 +314,6 @@
         assertEquals("null sort dir", SortDir.ASC, TableModel.sortDir(null));
     }
 
-
     @Test
     public void enumSort() {
         tm = new TableModel(FOO);
@@ -335,4 +335,83 @@
             assertEquals(UNEX_SORT + i, ordered[i], rows[i].get(FOO));
         }
     }
+
+    @Test
+    public void stringAnnotation() {
+        tm = new TableModel(FOO);
+        tm.addAnnotation(BAR, ZOO);
+        Collection<TableModel.Annot> annots = tm.getAnnotations();
+        assertEquals("wrong size", 1, annots.size());
+
+        TableModel.Annot annot = annots.iterator().next();
+        assertEquals("wrong key", BAR, annot.key());
+        assertEquals("wrong value", ZOO, annot.value());
+    }
+
+    private static final String K_INT = "int";
+    private static final String K_BOOL = "bool";
+    private static final String K_FLOAT = "float";
+    private static final String K_DOUBLE = "double";
+    private static final String K_ENUM = "enum";
+
+    private TableModel.Annot getAnnotation(Collection<TableModel.Annot> annots, String key) {
+        final TableModel.Annot[] annot = {null};
+        annots.forEach(a -> {
+            if (a.key().equals(key)) {
+                annot[0] = a;
+            }
+        });
+        return annot[0];
+    }
+
+    private void verifyCollectionContains(Collection<TableModel.Annot> annots,
+                                          String key, int i) {
+        TableModel.Annot a = getAnnotation(annots, key);
+        assertEquals("wrong int value", i, a.value());
+    }
+
+    private void verifyCollectionContains(Collection<TableModel.Annot> annots,
+                                          String key, boolean b) {
+        TableModel.Annot a = getAnnotation(annots, key);
+        assertEquals("wrong boolean value", b, a.value());
+    }
+
+    private void verifyCollectionContains(Collection<TableModel.Annot> annots,
+                                          String key, float f) {
+        TableModel.Annot a = getAnnotation(annots, key);
+        assertEquals("wrong float value", f, a.value());
+    }
+
+    private void verifyCollectionContains(Collection<TableModel.Annot> annots,
+                                          String key, double d) {
+        TableModel.Annot a = getAnnotation(annots, key);
+        assertEquals("wrong double value", d, a.value());
+    }
+
+    private void verifyCollectionContains(Collection<TableModel.Annot> annots,
+                                          String key, Enum<?> e) {
+        TableModel.Annot a = getAnnotation(annots, key);
+        assertEquals("wrong double value", e, a.value());
+    }
+
+    @Test
+    public void primitivesAnnotation() {
+        tm = new TableModel(FOO);
+        tm.addAnnotation(K_INT, 1);
+        tm.addAnnotation(K_BOOL, true);
+        tm.addAnnotation(K_FLOAT, 3.14f);
+        tm.addAnnotation(K_DOUBLE, 2.71828);
+        tm.addAnnotation(K_ENUM, StarWars.LUKE_SKYWALKER);
+
+        Collection<TableModel.Annot> annots = tm.getAnnotations();
+        assertEquals("wrong size", 5, annots.size());
+
+        verifyCollectionContains(annots, K_INT, 1);
+        verifyCollectionContains(annots, K_BOOL, true);
+        verifyCollectionContains(annots, K_FLOAT, 3.14f);
+        verifyCollectionContains(annots, K_DOUBLE, 2.71828);
+        verifyCollectionContains(annots, K_ENUM, StarWars.LUKE_SKYWALKER);
+    }
+
+    // TODO: add support for compound object value
 }
diff --git a/core/api/src/test/java/org/onosproject/ui/table/TableUtilsTest.java b/core/api/src/test/java/org/onosproject/ui/table/TableUtilsTest.java
index 4456dd3..66ac647 100644
--- a/core/api/src/test/java/org/onosproject/ui/table/TableUtilsTest.java
+++ b/core/api/src/test/java/org/onosproject/ui/table/TableUtilsTest.java
@@ -37,7 +37,7 @@
         tm.addRow().cell(FOO, 1).cell(BAR, 2);
         tm.addRow().cell(FOO, 3).cell(BAR, 4);
 
-        ArrayNode array = TableUtils.generateArrayNode(tm);
+        ArrayNode array = TableUtils.generateRowArrayNode(tm);
         Assert.assertEquals("wrong results", ARRAY_AS_STRING, array.toString());
     }