1 files changed, 73 insertions, 0 deletions
diff --git a/java/com/android/contacts/common/database/NoNullCursorAsyncQueryHandler.java b/java/com/android/contacts/common/database/NoNullCursorAsyncQueryHandler.java
new file mode 100644
index 000000000..d5e61354a
--- /dev/null
+++ b/java/com/android/contacts/common/database/NoNullCursorAsyncQueryHandler.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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 com.android.contacts.common.database;
+
+import android.content.AsyncQueryHandler;
+import android.content.ContentResolver;
+import android.database.Cursor;
+import android.net.Uri;
+
+/**
+ * An {@AsyncQueryHandler} that will never return a null cursor.
+ *
+ * <p>Instead, will return a {@link Cursor} with 0 records.
+ */
+public abstract class NoNullCursorAsyncQueryHandler extends AsyncQueryHandler {
+
+  public NoNullCursorAsyncQueryHandler(ContentResolver cr) {
+    super(cr);
+  }
+
+  @Override
+  public void startQuery(
+      int token,
+      Object cookie,
+      Uri uri,
+      String[] projection,
+      String selection,
+      String[] selectionArgs,
+      String orderBy) {
+    final CookieWithProjection projectionCookie = new CookieWithProjection(cookie, projection);
+    super.startQuery(token, projectionCookie, uri, projection, selection, selectionArgs, orderBy);
+  }
+
+  @Override
+  protected final void onQueryComplete(int token, Object cookie, Cursor cursor) {
+    CookieWithProjection projectionCookie = (CookieWithProjection) cookie;
+
+    super.onQueryComplete(token, projectionCookie.originalCookie, cursor);
+
+    if (cursor == null) {
+      cursor = new EmptyCursor(projectionCookie.projection);
+    }
+    onNotNullableQueryComplete(token, projectionCookie.originalCookie, cursor);
+  }
+
+  protected abstract void onNotNullableQueryComplete(int token, Object cookie, Cursor cursor);
+
+  /** Class to add projection to an existing cookie. */
+  private static class CookieWithProjection {
+
+    public final Object originalCookie;
+    public final String[] projection;
+
+    public CookieWithProjection(Object cookie, String[] projection) {
+      this.originalCookie = cookie;
+      this.projection = projection;
+    }
+  }
+}