GUI -- Beginnings of structure for topology Overlay API.
- Re-implemented RequestSummary / ShowSummary in Alt implementation.

Change-Id: Idb86c7bf3ede8f8815abcb488bbf9b0a7041ef79
diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/topo/overlay/AbstractSummaryGenerator.java b/web/gui/src/main/java/org/onosproject/ui/impl/topo/overlay/AbstractSummaryGenerator.java
new file mode 100644
index 0000000..ce840bd
--- /dev/null
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/topo/overlay/AbstractSummaryGenerator.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.
+ *
+ */
+
+package org.onosproject.ui.impl.topo.overlay;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.text.DecimalFormat;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Base implementation of a {@link SummaryGenerator}. Provides convenience
+ * methods for compiling a list of properties to be displayed in the summary
+ * panel on the UI.
+ */
+public abstract class AbstractSummaryGenerator implements SummaryGenerator {
+    private static final String NUMBER_FORMAT = "#,###";
+    private static final DecimalFormat DF = new DecimalFormat(NUMBER_FORMAT);
+    private static final ObjectMapper MAPPER = new ObjectMapper();
+
+    private final List<Prop> props = new ArrayList<>();
+    private String iconId;
+    private String title;
+
+    /**
+     * Constructs a summary generator without specifying the icon ID or title.
+     * It is expected that the title (and optionally the icon ID) will be set
+     * later via {@link #title(String)} (and {@link #iconId(String)}), before
+     * {@link #buildObjectNode()} is invoked to generate the message payload.
+     */
+    public AbstractSummaryGenerator() {
+    }
+
+    /**
+     * Constructs a summary generator that uses the specified iconId ID and
+     * title in its generated output.
+     *
+     * @param iconId iconId ID
+     * @param title title
+     */
+    public AbstractSummaryGenerator(String iconId, String title) {
+        this.iconId = iconId;
+        this.title = title;
+    }
+
+    /**
+     * Subclasses need to provide an implementation.
+     *
+     * @return the summary payload
+     */
+    @Override
+    public abstract ObjectNode generateSummary();
+
+    /**
+     * Formats the given number into a string, using comma separator.
+     *
+     * @param number the number
+     * @return formatted as a string
+     */
+    protected String format(Number number) {
+        return DF.format(number);
+    }
+
+    /**
+     * Sets the iconId ID to use.
+     *
+     * @param iconId iconId ID
+     */
+    protected void iconId(String iconId) {
+        this.iconId = iconId;
+    }
+
+    /**
+     * Sets the summary panel title.
+     *
+     * @param title the title
+     */
+    protected void title(String title) {
+        this.title = title;
+    }
+
+    /**
+     * Clears out the cache of properties.
+     */
+    protected void clearProps() {
+        props.clear();
+    }
+
+    /**
+     * Adds a property to the summary. Note that the value is converted to
+     * a string by invoking the <code>toString()</code> method on it.
+     *
+     * @param label the label
+     * @param value the value
+     */
+    protected void prop(String label, Object value) {
+        props.add(new Prop(label, value));
+    }
+
+    /**
+     * Adds a separator to the summary; when rendered on the client, a visible
+     * break between properties.
+     */
+    protected void separator() {
+        props.add(new Prop("-", ""));
+    }
+
+    /**
+     * Builds an object node from the current state of the summary generator.
+     *
+     * @return summary payload as JSON object node
+     */
+    protected ObjectNode buildObjectNode() {
+        ObjectNode result = MAPPER.createObjectNode();
+        // NOTE: "id" and "type" are currently used for title and iconID
+        //  so that this structure can be "re-used" with detail panel payloads
+        result.put("id", title).put("type", iconId);
+
+        ObjectNode pnode = MAPPER.createObjectNode();
+        ArrayNode porder = MAPPER.createArrayNode();
+
+        for (Prop p : props) {
+            porder.add(p.label);
+            pnode.put(p.label, p.value);
+        }
+        result.set("propOrder", porder);
+        result.set("props", pnode);
+
+        return result;
+    }
+
+    // ===================================================================
+
+    /**
+     * Abstraction of a property, that is, a label-value pair.
+     */
+    private static class Prop {
+        private final String label;
+        private final String value;
+
+        public Prop(String label, Object value) {
+            this.label = label;
+            this.value = value.toString();
+        }
+    }
+}