Add the Physical Web to Chrome on Android

chrome/android/java/src/org/chromium/chrome/browser/physicalweb/UrlManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/physicalweb/UrlManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/physicalweb/UrlManager.java b/chrome/android/java/src/org/chromium/chrome/browser/physicalweb/UrlManager.java
new file mode 100644
index 0000000000000000000000000000000000000000..30c093ffcd5202cbae4610089af23809924b8a58
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/physicalweb/UrlManager.java
@@ -0,0 +1,124 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.physicalweb;
+
+import android.app.Notification;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.res.Resources;
+import android.support.v4.app.NotificationCompat;
+import android.support.v4.app.NotificationManagerCompat;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.notifications.NotificationConstants;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * This class stores URLs and surfaces notifications to the user.
+ */
+public class UrlManager {
+    private static final String TAG = "PhysicalWeb";
+    private static final String PREFS_NAME = "org.chromium.chrome.browser.physicalweb.URL_CACHE";
+    private static final String PREFS_VERSION_KEY = "version";
+    private static final String PREFS_URLS_KEY = "urls";
+    private static final int PREFS_VERSION = 1;
+    private static UrlManager sInstance = null;
+    private final Context mContext;
+    private final NotificationManagerCompat mNotificationManager;
+
+    /**
+     * Construct the UrlManager.
+     * @param context An instance of android.content.Context
+     */
+    public UrlManager(Context context) {
+        mContext = context;
+        mNotificationManager = NotificationManagerCompat.from(context);
+    }
+
+    /**
+     * Get a singleton instance of this class.
+     * @param context An instance of android.content.Context.
+     * @return A singleton instance of this class.
+     */
+    public static UrlManager getInstance(Context context) {
+        if (sInstance == null) {
+            sInstance = new UrlManager(context);
+        }
+        return sInstance;
+    }
+
+    /**
+     * Add a URL to the store of URLs.
+     * This method additionally updates the Physical Web notification.
+     * @param url The URL to add.
+     */
+    public void addUrl(String url) {
+        Set<String> urls = getCachedUrls();
+        urls.add(url);
+        putCachedUrls(urls);
+        updateNotification(urls);
+    }
+
+    /**
+     * Remove a URL to the store of URLs.
+     * This method additionally updates the Physical Web notification.
+     * @param url The URL to remove.
+     */
+    public void removeUrl(String url) {
+        Set<String> urls = getCachedUrls();
+        urls.remove(url);
+        putCachedUrls(urls);
+        updateNotification(urls);
+    }
+
+    private Set<String> getCachedUrls() {
+        // Check the version.
+        SharedPreferences prefs = mContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
+        int prefsVersion = prefs.getInt(PREFS_VERSION_KEY, 0);
+        if (prefsVersion != PREFS_VERSION) {
+            return new HashSet<String>();
+        }
+
+        // Restore the cached urls.
+        return prefs.getStringSet(PREFS_URLS_KEY, new HashSet<String>());
+    }
+
+    private void putCachedUrls(Set<String> urls) {
+        // Write the version.
+        SharedPreferences prefs = mContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = prefs.edit();
+        editor.putInt(PREFS_VERSION_KEY, PREFS_VERSION);
+
+        // Write the urls.
+        editor.putStringSet(PREFS_URLS_KEY, urls);
+        editor.apply();
+    }
+
+    private void updateNotification(Set<String> urls) {
+        if (urls.isEmpty()) {
+            mNotificationManager.cancel(NotificationConstants.NOTIFICATION_ID_PHYSICAL_WEB);
+            return;
+        }
+
+        // Get values to display.
+        String displayUrl = urls.iterator().next();
+        Resources resources = mContext.getResources();
+        String title = resources.getQuantityString(R.plurals.physical_web_notification_title,
+                                                   urls.size(), urls.size());
+
+        // Create the notification.
+        Notification notification = new NotificationCompat.Builder(mContext)
+                .setSmallIcon(R.drawable.ic_physical_web_notification)
+                .setContentTitle(title)
+                .setContentText(displayUrl)
+                .setPriority(NotificationCompat.PRIORITY_MIN)
+                .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
+                .build();
+        mNotificationManager.notify(NotificationConstants.NOTIFICATION_ID_PHYSICAL_WEB,
+                                    notification);
+    }
+}