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diff --git a/app/src/main/java/org/dmfs/provider/tasks/TaskContract.java b/app/src/main/java/org/dmfs/provider/tasks/TaskContract.java
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+/*
+ * Copyright (C) 2012 Marten Gajda <marten@dmfs.org>
+ *
+ * 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.dmfs.provider.tasks;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import android.content.ContentResolver;
+import android.net.Uri;
+
+
+/**
+ * Task contract. This class defines the interface to the task provider.
+ * <p>
+ * TODO: Add missing javadoc.
+ * </p>
+ * <p>
+ * TODO: Specify extended properties
+ * </p>
+ * <p>
+ * TODO: Add CONTENT_URI for the attachment store.
+ * </p>
+ * <p>
+ * TODO: Also, we could use some refactoring...
+ * </p>
+ * 
+ * @author Marten Gajda <marten@dmfs.org>
+ * @author Tobias Reinsch <tobias@dmfs.org>
+ */
+public final class TaskContract
+{
+
+	private static Map<String, UriFactory> sUriFactories = new HashMap<String, UriFactory>(4);
+
+	/**
+	 * URI parameter to signal that the caller is a sync adapter.
+	 */
+	public static final String CALLER_IS_SYNCADAPTER = "caller_is_syncadapter";
+
+	/**
+	 * URI parameter to signal the request of the extended properties of a task.
+	 */
+	public static final String LOAD_PROPERTIES = "load_properties";
+
+	/**
+	 * URI parameter to submit the account name of the account we operate on.
+	 */
+	public static final String ACCOUNT_NAME = "account_name";
+
+	/**
+	 * URI parameter to submit the account type of the account we operate on.
+	 */
+	public static final String ACCOUNT_TYPE = "account_type";
+
+	/**
+	 * Account type for local, unsynced task lists.
+	 */
+	public static final String LOCAL_ACCOUNT = "LOCAL";
+
+
+	/**
+	 * Private constructor to prevent instantiation.
+	 */
+	private TaskContract()
+	{
+	}
+
+
+	/**
+	 * Get the base content {@link Uri} using the given authority.
+	 * 
+	 * @param authority
+	 *            The authority.
+	 * @return A {@link Uri}.
+	 */
+	public final static Uri getContentUri(String authority)
+	{
+		return getUriFactory(authority).getUri();
+	}
+
+	/**
+	 * A set of columns for synchronization purposes. These columns exist in {@link Tasks} and in {@link TaskLists} but have different meanings. Only sync
+	 * adapters are allowed to change these values.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface CommonSyncColumns
+	{
+
+		/**
+		 * A unique Sync ID as set by the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String _SYNC_ID = "_sync_id";
+
+		/**
+		 * Sync version as set by the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC_VERSION = "sync_version";
+
+		/**
+		 * Indicates that a task or a task list has been changed.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String _DIRTY = "_dirty";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC1 = "sync1";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC2 = "sync2";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC3 = "sync3";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC4 = "sync4";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC5 = "sync5";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC6 = "sync6";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC7 = "sync7";
+
+		/**
+		 * A general purpose column for the sync adapter.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SYNC8 = "sync8";
+
+	}
+
+	/**
+	 * Additional sync columns for task lists.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface TaskListSyncColumns
+	{
+
+		/**
+		 * The name of the account this list belongs to. This field is write-once.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String ACCOUNT_NAME = "account_name";
+
+		/**
+		 * The type of the account this list belongs to. This field is write-once.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String ACCOUNT_TYPE = "account_type";
+	}
+
+	/**
+	 * Additional sync columns for tasks.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface TaskSyncColumns
+	{
+		/**
+		 * The UID of a task. This is field can be changed by a sync adapter only.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String _UID = "_uid";
+
+		/**
+		 * Deleted flag of a task. This is set to <code>1</code> by the content provider when a task app deletes a task. The sync adapter has to remove the task
+		 * again to finish the removal. This value is <strong>read-only</strong>.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String _DELETED = "_deleted";
+	}
+
+	/**
+	 * Data columns of task lists.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface TaskListColumns
+	{
+
+		/**
+		 * List ID.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String _ID = "_id";
+
+		/**
+		 * The name of the task list.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String LIST_NAME = "list_name";
+
+		/**
+		 * The color of this list as integer (0xaarrggbb). Only the sync adapter can change this.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String LIST_COLOR = "list_color";
+
+		/**
+		 * The access level a user has on this list. <strong>This value is not used yet, sync adapters should set it to <code>0</code></strong>.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String ACCESS_LEVEL = "list_access_level";
+
+		/**
+		 * Indicates that a task list is set to be visible.
+		 * <p>
+		 * Value: Integer (0 or 1)
+		 * </p>
+		 */
+		public static final String VISIBLE = "visible";
+
+		/**
+		 * Indicates that a task list is set to be synced.
+		 * <p>
+		 * Value: Integer (0 or 1)
+		 * </p>
+		 */
+		public static final String SYNC_ENABLED = "sync_enabled";
+
+		/**
+		 * The email address of the list owner.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String OWNER = "list_owner";
+
+	}
+
+	/**
+	 * The task list table holds one entry for each task list.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public static final class TaskLists implements TaskListColumns, TaskListSyncColumns, CommonSyncColumns
+	{
+		static final String CONTENT_URI_PATH = "tasklists";
+
+		/**
+		 * The default sort order.
+		 */
+		public static final String DEFAULT_SORT_ORDER = ACCOUNT_NAME + ", " + LIST_NAME;
+
+		/**
+		 * An array of columns only a sync adapter is allowed to change.
+		 */
+		public static final String[] SYNC_ADAPTER_COLUMNS = new String[] { ACCESS_LEVEL, _DIRTY, OWNER, SYNC1, SYNC2, SYNC3, SYNC4, SYNC5, SYNC6, SYNC7, SYNC8,
+			_SYNC_ID, SYNC_VERSION, };
+
+
+		/**
+		 * Get the task list content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+	}
+
+	/**
+	 * Task data columns. Defines all the values a task can have at most once.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface TaskColumns
+	{
+
+		/**
+		 * The row id of a task. This value is <strong>read-only</strong>
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String _ID = "_id";
+
+		/**
+		 * The id of the list this task belongs to. This value is <strong>write-once</strong> and must not be <code>null</code>.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String LIST_ID = "list_id";
+
+		/**
+		 * The title of the task.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String TITLE = "title";
+
+		/**
+		 * The location of the task.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String LOCATION = "location";
+
+		/**
+		 * A geographic location related to the task. The should be a string in the format "longitude,latitude".
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String GEO = "geo";
+
+		/**
+		 * The description of a task.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String DESCRIPTION = "description";
+
+		/**
+		 * An URL for this task. Must be a valid URL if not <code>null</code>-
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String URL = "url";
+
+		/**
+		 * The email address of the organizer if any, {@code null} otherwise.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String ORGANIZER = "organizer";
+
+		/**
+		 * The priority of a task. This is an Integer between zero and 9. Zero means there is no priority set. 1 is the highest priority and 9 the lowest.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String PRIORITY = "priority";
+
+		/**
+		 * The default value of {@link #PRIORITY}.
+		 */
+		public static final int PRIORITY_DEFAULT = 0;
+
+		/**
+		 * The classification of a task. This value must be either <code>null</code> or one of {@link #CLASSIFICATION_PUBLIC}, {@link #CLASSIFICATION_PRIVATE},
+		 * {@link #CLASSIFICATION_CONFIDENTIAL}.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String CLASSIFICATION = "class";
+
+		/**
+		 * Classification value for public tasks.
+		 */
+		public static final int CLASSIFICATION_PUBLIC = 0;
+
+		/**
+		 * Classification value for private tasks.
+		 */
+		public static final int CLASSIFICATION_PRIVATE = 1;
+
+		/**
+		 * Classification value for confidential tasks.
+		 */
+		public static final int CLASSIFICATION_CONFIDENTIAL = 2;
+
+		/**
+		 * Default value of {@link #CLASSIFICATION}.
+		 */
+		public static final Integer CLASSIFICATION_DEFAULT = null;
+
+		/**
+		 * Date of completion of this task in milliseconds since the epoch or {@code null} if this task has not been completed yet.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String COMPLETED = "completed";
+
+		/**
+		 * Indicates that the date of completion is an all-day date.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String COMPLETED_IS_ALLDAY = "completed_is_allday";
+
+		/**
+		 * A number between 0 and 100 that indicates the progress of the task or <code>null</code>.
+		 * <p>
+		 * Value: Integer (0-100)
+		 * </p>
+		 */
+		public static final String PERCENT_COMPLETE = "percent_complete";
+
+		/**
+		 * The status of this task. One of {@link #STATUS_NEEDS_ACTION},{@link #STATUS_IN_PROCESS}, {@link #STATUS_COMPLETED}, {@link #STATUS_CANCELLED}.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String STATUS = "status";
+
+		/**
+		 * A specific status indicating that nothing has been done yet.
+		 */
+		public static final int STATUS_NEEDS_ACTION = 0;
+
+		/**
+		 * A specific status indicating that some work has been done.
+		 */
+		public static final int STATUS_IN_PROCESS = 1;
+
+		/**
+		 * A specific status indicating that the task is completed.
+		 */
+		public static final int STATUS_COMPLETED = 2;
+
+		/**
+		 * A specific status indicating that the task has been cancelled.
+		 */
+		public static final int STATUS_CANCELLED = 3;
+
+		/**
+		 * The default status is "needs action".
+		 */
+		public static final int STATUS_DEFAULT = STATUS_NEEDS_ACTION;
+
+		/**
+		 * A flag that indicates a task is new (i.e. not work has been done yet). This flag is <strong>read-only</strong>. Its value is <code>1</code> when
+		 * {@link #STATUS} equals {@link #STATUS_NEEDS_ACTION} and <code>0</code> otherwise.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String IS_NEW = "is_new";
+
+		/**
+		 * A flag that indicates a task is closed (no more work has to be done). This flag is <strong>read-only</strong>. Its value is <code>1</code> when
+		 * {@link #STATUS} equals {@link #STATUS_COMPLETED} or {@link #STATUS_CANCELLED} and <code>0</code> otherwise.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String IS_CLOSED = "is_closed";
+
+		/**
+		 * An individual color for this task in the format 0xaarrggbb or {@code null} to use {@link TaskListColumns#LIST_COLOR} instead.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String TASK_COLOR = "task_color";
+
+		/**
+		 * When this task starts in milliseconds since the epoch.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String DTSTART = "dtstart";
+
+		/**
+		 * Boolean: flag that indicates that this is an all-day task.
+		 */
+		public static final String IS_ALLDAY = "is_allday";
+
+		/**
+		 * When this task has been created in milliseconds since the epoch.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String CREATED = "created";
+
+		/**
+		 * When this task had been modified the last time in milliseconds since the epoch.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String LAST_MODIFIED = "last_modified";
+
+		/**
+		 * String: An Olson Id of the time zone of this task. If this value is <code>null</code>, it's automatically replaced by the local time zone.
+		 */
+		public static final String TZ = "tz";
+
+		/**
+		 * When this task is due in milliseconds since the epoch. Only one of {@link #DUE} or {@link #DURATION} must be supplied (or none of both if the task
+		 * has no due date).
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String DUE = "due";
+
+		/**
+		 * The duration of this task. Only one of {@link #DUE} or {@link #DURATION} must be supplied (or none of both if the task has no due date). Setting a
+		 * {@link #DURATION} is not allowed when {@link #DTSTART} is <code>null</code>. The Value must be a duration string as in <a
+		 * href="http://tools.ietf.org/html/rfc5545#section-3.3.6">RFC 5545 Section 3.3.6</a>.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String DURATION = "duration";
+
+		/**
+		 * A comma separated list of time Strings in RFC 5545 format (see <a href="http://tools.ietf.org/html/rfc5545#section-3.3.4">RFC 5545 Section 3.3.4</a>
+		 * and <a href="http://tools.ietf.org/html/rfc5545#section-3.3.5">RFC 5545 Section 3.3.5</a>) that contains dates of instances of e recurring task.
+		 * All-day tasks must use the DATE format specified in section 3.3.4 of RFC 5545.
+		 * 
+		 * This value must be {@code null} for exception instances.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String RDATE = "rdate";
+
+		/**
+		 * A comma separated list of time Strings in RFC 5545 format (see <a href="http://tools.ietf.org/html/rfc5545#section-3.3.4">RFC 5545 Section 3.3.4</a>
+		 * and <a href="http://tools.ietf.org/html/rfc5545#section-3.3.5">RFC 5545 Section 3.3.5</a>) that contains dates of exceptions of a recurring task.
+		 * All-day tasks must use the DATE format specified in section 3.3.4 of RFC 5545.
+		 * 
+		 * This value must be {@code null} for exception instances.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String EXDATE = "exdate";
+
+		/**
+		 * A recurrence rule as specified in <a href="http://tools.ietf.org/html/rfc5545#section-3.3.10">RFC 5545 Section 3.3.10</a>.
+		 * 
+		 * This value must be {@code null} for exception instances.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String RRULE = "rrule";
+
+		/**
+		 * The _sync_id of the original event if this is an exception, <code>null</code> otherwise. Only one of {@link #ORIGINAL_INSTANCE_SYNC_ID} or
+		 * {@link #ORIGINAL_INSTANCE_ID} must be set if this task is an exception. The other one will be updated by the content provider.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String ORIGINAL_INSTANCE_SYNC_ID = "original_instance_sync_id";
+
+		/**
+		 * The row id of the original event if this is an exception, <code>null</code> otherwise. Only one of {@link #ORIGINAL_INSTANCE_SYNC_ID} or
+		 * {@link #ORIGINAL_INSTANCE_ID} must be set if this task is an exception. The other one will be updated by the content provider.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String ORIGINAL_INSTANCE_ID = "original_instance_id";
+
+		/**
+		 * The time in milliseconds since the Epoch of the original instance that is overridden by this instance or <code>null</code> if this task is not an
+		 * exception.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String ORIGINAL_INSTANCE_TIME = "original_instance_time";
+
+		/**
+		 * A flag indicating that the original instance was an all-day task.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 */
+		public static final String ORIGINAL_INSTANCE_ALLDAY = "original_instance_allday";
+
+		/**
+		 * The row id of the parent task. <code>null</code> if the task has no parent task.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String PARENT_ID = "parent_id";
+
+		/**
+		 * The sorting of this task under it's parent task.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 */
+		public static final String SORTING = "sorting";
+
+		/**
+		 * Indicates how many alarms a task has. <code>0</code> means the task has no alarms.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * 
+		 */
+		public static final String HAS_ALARMS = "has_alarms";
+	}
+
+	/**
+	 * Columns that are valid in a search query.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface TaskSearchColumns
+	{
+		/**
+		 * The score of a task in a search result. It's an indicator for the relevance of the task. Value is in (0, 1.0] where 0 would be "no relevance" at all
+		 * (though the result doesn't contain such tasks).
+		 * <p>
+		 * Value: Float
+		 * </p>
+		 */
+		public final static String SCORE = "score";
+	}
+
+	/**
+	 * The task table stores the data of all tasks.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public static final class Tasks implements TaskColumns, CommonSyncColumns, TaskSyncColumns, TaskSearchColumns
+	{
+		/**
+		 * The name of the account the task belongs to. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String ACCOUNT_NAME = TaskLists.ACCOUNT_NAME;
+
+		/**
+		 * The type of the account the task belongs to. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String ACCOUNT_TYPE = TaskLists.ACCOUNT_TYPE;
+
+		/**
+		 * The name of the list this task belongs to as integer (0xaarrggbb). This is auto-derived from the list the task belongs to. Do not write this value
+		 * here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_NAME = TaskLists.LIST_NAME;
+		/**
+		 * The color of the list this task belongs to as integer (0xaarrggbb). This is auto-derived from the list the task belongs to. Do not write this value
+		 * here. To change the color of an individual task use {@code TASK_COLOR} instead.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_COLOR = TaskLists.LIST_COLOR;
+
+		/**
+		 * The owner of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_OWNER = TaskLists.OWNER;
+
+		/**
+		 * The access level of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_ACCESS_LEVEL = TaskLists.ACCESS_LEVEL;
+
+		/**
+		 * The visibility of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String VISIBLE = "visible";
+
+		static final String CONTENT_URI_PATH = "tasks";
+
+		static final String SEARCH_URI_PATH = "tasks_search";
+
+		static final String SEARCH_QUERY_PARAMETER = "q";
+
+		public static final String DEFAULT_SORT_ORDER = DUE;
+
+		public static final String[] SYNC_ADAPTER_COLUMNS = new String[] { _DIRTY, SYNC1, SYNC2, SYNC3, SYNC4, SYNC5, SYNC6, SYNC7, SYNC8, _SYNC_ID,
+			SYNC_VERSION, };
+
+
+		/**
+		 * Get the tasks content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+
+		public final static Uri getSearchUri(String authority, String query)
+		{
+			Uri.Builder builder = getUriFactory(authority).getUri(SEARCH_URI_PATH).buildUpon();
+			builder.appendQueryParameter(SEARCH_QUERY_PARAMETER, Uri.encode(query));
+			return builder.build();
+		}
+	}
+
+	/**
+	 * Columns of a task instance.
+	 * 
+	 * @author Yannic Ahrens <yannic@dmfs.org>
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface InstanceColumns
+	{
+		/**
+		 * _ID of task this instance belongs to.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String TASK_ID = "task_id";
+
+		/**
+		 * The start date of an instance in milliseconds since the epoch or <code>null</code> if the instance has no start date. At present this is read only.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String INSTANCE_START = "instance_start";
+
+		/**
+		 * The due date of an instance in milliseconds since the epoch or <code>null</code> if the instance has no due date. At present this is read only.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String INSTANCE_DUE = "instance_due";
+
+		/**
+		 * This column should be used in an order clause to sort instances by due date. It contains a slightly modified start date that takes allday tasks into
+		 * account.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String INSTANCE_START_SORTING = "instance_start_sorting";
+
+		/**
+		 * This column should be used in an order clause to sort instances by due date. It contains a slightly modified due date that takes allday tasks into
+		 * account.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String INSTANCE_DUE_SORTING = "instance_due_sorting";
+
+		/**
+		 * The duration of an instance in milliseconds or <code>null</code> if the instance has only one of start or due date or none of both. At present this
+		 * is read only.
+		 * <p>
+		 * Value: Long
+		 * </p>
+		 */
+		public static final String INSTANCE_DURATION = "instance_duration";
+
+	}
+
+	/**
+	 * Instances of a task. At present this table is read only. Currently it contains exactly one entry per task (and task exception), so it's merely a copy of
+	 * {@link Tasks}.
+	 * <p>
+	 * TODO: Insert all instances of recurring the tasks.
+	 * </p>
+	 * <p>
+	 * TODO: In later releases it's planned to provide a convenient interface to add, change or delete task instances via this URI.
+	 * </p>
+	 * 
+	 * @author Yannic Ahrens <yannic@dmfs.org>
+	 */
+	public static final class Instances implements TaskColumns, InstanceColumns
+	{
+
+		/**
+		 * The name of the account the task belongs to. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String ACCOUNT_NAME = TaskLists.ACCOUNT_NAME;
+
+		/**
+		 * The type of the account the task belongs to. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String ACCOUNT_TYPE = TaskLists.ACCOUNT_TYPE;
+
+		/**
+		 * The name of the list this task belongs to as integer (0xaarrggbb). This is auto-derived from the list the task belongs to. Do not write this value
+		 * here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_NAME = TaskLists.LIST_NAME;
+		/**
+		 * The color of the list this task belongs to as integer (0xaarrggbb). This is auto-derived from the list the task belongs to. Do not write this value
+		 * here. To change the color of an individual task use {@code TASK_COLOR} instead.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_COLOR = TaskLists.LIST_COLOR;
+
+		/**
+		 * The owner of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: String
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_OWNER = TaskLists.OWNER;
+
+		/**
+		 * The access level of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String LIST_ACCESS_LEVEL = TaskLists.ACCESS_LEVEL;
+
+		/**
+		 * The visibility of the list this task belongs. This is auto-derived from the list the task belongs to. Do not write this value here.
+		 * <p>
+		 * Value: Integer
+		 * </p>
+		 * <p>
+		 * read-only
+		 * </p>
+		 */
+		public static final String VISIBLE = "visible";
+
+		static final String CONTENT_URI_PATH = "instances";
+
+		public static final String DEFAULT_SORT_ORDER = INSTANCE_DUE_SORTING;
+
+
+		/**
+		 * Get the instances content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+	}
+
+	/**
+	 * Available values in Categories.
+	 * 
+	 * Categories are per account. It's up to the front-end to ensure consistency of category colors across accounts.
+	 * 
+	 * @author Marten Gajda <marten@dmfs.org>
+	 */
+	public interface CategoriesColumns
+	{
+
+		public static final String _ID = "_id";
+
+		public static final String ACCOUNT_NAME = "account_name";
+
+		public static final String ACCOUNT_TYPE = "account_type";
+
+		public static final String NAME = "name";
+
+		public static final String COLOR = "color";
+	}
+
+	public static final class Categories implements CategoriesColumns
+	{
+
+		static final String CONTENT_URI_PATH = "categories";
+
+		public static final String DEFAULT_SORT_ORDER = NAME;
+
+
+		/**
+		 * Get the categories content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+	}
+
+	public interface AlarmsColumns
+	{
+		public static final String ALARM_ID = "alarm_id";
+
+		public static final String LAST_TRIGGER = "last_trigger";
+
+		public static final String NEXT_TRIGGER = "next_trigger";
+	}
+
+	public static final class Alarms implements AlarmsColumns
+	{
+
+		static final String CONTENT_URI_PATH = "alarms";
+
+
+		/**
+		 * Get the alarms content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+	}
+
+	public interface PropertySyncColumns
+	{
+		public static final String SYNC1 = "prop_sync1";
+
+		public static final String SYNC2 = "prop_sync2";
+
+		public static final String SYNC3 = "prop_sync3";
+
+		public static final String SYNC4 = "prop_sync4";
+
+		public static final String SYNC5 = "prop_sync5";
+
+		public static final String SYNC6 = "prop_sync6";
+
+		public static final String SYNC7 = "prop_sync7";
+
+		public static final String SYNC8 = "prop_sync8";
+	}
+
+	public interface PropertyColumns
+	{
+
+		public static final String PROPERTY_ID = "property_id";
+
+		public static final String TASK_ID = "task_id";
+
+		public static final String MIMETYPE = "mimetype";
+
+		public static final String VERSION = "prop_version";
+
+		public static final String DATA0 = "data0";
+
+		public static final String DATA1 = "data1";
+
+		public static final String DATA2 = "data2";
+
+		public static final String DATA3 = "data3";
+
+		public static final String DATA4 = "data4";
+
+		public static final String DATA5 = "data5";
+
+		public static final String DATA6 = "data6";
+
+		public static final String DATA7 = "data7";
+
+		public static final String DATA8 = "data8";
+
+		public static final String DATA9 = "data9";
+
+		public static final String DATA10 = "data10";
+
+		public static final String DATA11 = "data11";
+
+		public static final String DATA12 = "data12";
+
+		public static final String DATA13 = "data13";
+
+		public static final String DATA14 = "data14";
+
+		public static final String DATA15 = "data15";
+	}
+
+	public static final class Properties implements PropertySyncColumns, PropertyColumns
+	{
+
+		static final String CONTENT_URI_PATH = "properties";
+
+		public static final String DEFAULT_SORT_ORDER = DATA0;
+
+
+		/**
+		 * Get the properties content {@link Uri} using the given authority.
+		 * 
+		 * @param authority
+		 *            The authority.
+		 * @return A {@link Uri}.
+		 */
+		public final static Uri getContentUri(String authority)
+		{
+			return getUriFactory(authority).getUri(CONTENT_URI_PATH);
+		}
+
+	}
+
+	public interface Property
+	{
+		/**
+		 * Attached documents.
+		 * <p>
+		 * <strong>Note:<strong> Attachments are write-once. To change an attachment you'll have to remove and re-add it.
+		 * </p>
+		 * 
+		 * @author Marten Gajda <marten@dmfs.org>
+		 */
+		public static interface Attachment extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/attachment";
+
+			/**
+			 * URL of the attachment. This is the link that points to the attached resource.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String URL = DATA1;
+
+			/**
+			 * The display name of the attachment, if any.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String DISPLAY_NAME = DATA2;
+
+			/**
+			 * Content-type of the attachment.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String FORMAT = DATA3;
+
+			/**
+			 * File size of the attachment or <code>-1</code> if unknown.
+			 * <p>
+			 * Value: Long
+			 * </p>
+			 */
+			public final static String SIZE = DATA4;
+
+			/**
+			 * A content {@link Uri} that can be used to retrieve the attachment. Sync adapters can set this field if they know how to download the attachment
+			 * without going through the browser.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String CONTENT_URI = DATA5;
+
+		}
+
+		public static interface Attendee extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/attendee";
+
+			/**
+			 * Name of the contact, if known.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String NAME = DATA0;
+
+			/**
+			 * Email address of the contact.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String EMAIL = DATA1;
+
+			public final static String ROLE = DATA2;
+
+			public final static String STATUS = DATA3;
+
+			public final static String RSVP = DATA4;
+		}
+
+		/**
+		 * Categories are immutable. For creation is either the category id or name necessary
+		 * 
+		 */
+		public static interface Category extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/category";
+
+			/**
+			 * Row id of the category.
+			 * <p>
+			 * Value: Long
+			 * </p>
+			 */
+			public final static String CATEGORY_ID = DATA0;
+
+			/**
+			 * The name of the category
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String CATEGORY_NAME = DATA1;
+
+			/**
+			 * The decimal coded color of the category
+			 * <p>
+			 * Value: Integer
+			 * </p>
+			 * <p>
+			 * read-only
+			 * </p>
+			 */
+			public final static String CATEGORY_COLOR = DATA2;
+		}
+
+		public static interface Comment extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/comment";
+
+			/**
+			 * Comment text.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String COMMENT = DATA0;
+
+			/**
+			 * Language code of the comment as defined in <a href="https://tools.ietf.org/html/rfc5646">RFC5646</a> or <code>null</code>.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String LANGUAGE = DATA1;
+		}
+
+		public static interface Contact extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/contact";
+
+			public final static String NAME = DATA0;
+
+			public final static String LANGUAGE = DATA1;
+		}
+
+		/**
+		 * Relations of a task.
+		 * <p>
+		 * When writing a relation, exactly one of {@link #RELATED_ID}, {@link #RELATED_UID} or {@link #RELATED_URI} must be given. {@link #RELATED_CONTENT_URI}
+		 * will be populated automatically if possible.
+		 * </p>
+		 */
+		public static interface Relation extends PropertyColumns
+		{
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/relation";
+
+			/**
+			 * The row id of the related task. May be <code>-1</code> if the property doesn't refer to a task in this database or if it doesn't refer to a task
+			 * at all.
+			 * <p>
+			 * Value: long
+			 * </p>
+			 */
+			public final static String RELATED_ID = DATA1;
+
+			/**
+			 * The relation type. This must be the ordinal value of a {@link RelType}.
+			 * <p>
+			 * Value: int
+			 * </p>
+			 */
+			public final static String RELATED_TYPE = DATA2;
+
+			/**
+			 * The UID of the related object.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String RELATED_UID = DATA3;
+
+			/**
+			 * The URI of a related object.
+			 * <p>
+			 * Value: String (URI)
+			 * </p>
+			 */
+			public final static String RELATED_URI = DATA4;
+
+			/**
+			 * The URI of a related object in another Android content provider. If the object is a task in this database, this is <code>null</code>. If the
+			 * related object is an event or note this field may contain the content URI to the object.
+			 * <p>
+			 * Value: String (URI)
+			 * </p>
+			 * <p>
+			 * This field is read-only.
+			 * </p>
+			 */
+			public final static String RELATED_CONTENT_URI = DATA5;
+
+			/**
+			 * An optional gap value for temporal relationships.
+			 * <p>
+			 * Value: duration string
+			 * </p>
+			 */
+			public final static String GAP = DATA6;
+
+			/**
+			 * Valid values for the {@link Relation#RELATED_TYPE} field. Note that the field actually takes the ordinal value of these.
+			 */
+			public enum RelType
+			{
+				/**
+				 * The related object is the parent of the object owning this relation.
+				 */
+				PARENT,
+
+				/**
+				 * The related object is the child of the object owning this relation.
+				 */
+				CHILD,
+
+				/**
+				 * The related object is a sibling of the object owning this relation.
+				 */
+				SIBLING,
+
+				DEPENDS_ON,
+
+				REFID,
+
+				STRUCTURED_CATEGORY,
+
+				FINISHTOSTART,
+
+				FINISHTOFINISH,
+
+				STARTTOFINISH,
+
+				STARTTOSTART;
+			}
+		}
+
+		public static interface Alarm extends PropertyColumns
+		{
+
+			public static final int ALARM_TYPE_NOTHING = 0;
+
+			public static final int ALARM_TYPE_MESSAGE = 1;
+
+			public static final int ALARM_TYPE_EMAIL = 2;
+
+			public static final int ALARM_TYPE_SMS = 3;
+
+			public static final int ALARM_TYPE_SOUND = 4;
+
+			public static final int ALARM_REFERENCE_DUE_DATE = 1;
+
+			public static final int ALARM_REFERENCE_START_DATE = 2;
+
+			/**
+			 * The mime-type of this property.
+			 */
+			public final static String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/alarm";
+
+			/**
+			 * Number of minutes from the reference date when the alarm goes off. If the value is < 0 the alarm will go off after the reference date.
+			 * <p>
+			 * Value: Integer
+			 * </p>
+			 */
+			public final static String MINUTES_BEFORE = DATA0;
+
+			/**
+			 * The reference date for the alarm. Either {@link ALARM_REFERENCE_DUE_DATE} or {@link ALARM_REFERENCE_START_DATE}.
+			 * <p>
+			 * Value: Integer
+			 * </p>
+			 */
+			public final static String REFERENCE = DATA1;
+
+			/**
+			 * A message that appears with the alarm.
+			 * <p>
+			 * Value: String
+			 * </p>
+			 */
+			public final static String MESSAGE = DATA2;
+
+			/**
+			 * The type of the alarm. Use the provided alarm types {@link ALARM_TYPE_MESSAGE}, {@link ALARM_TYPE_SOUND}, {@link ALARM_TYPE_NOTHING},
+			 * {@link ALARM_TYPE_EMAIL} and {@link ALARM_TYPE_SMS}.
+			 * <p>
+			 * Value: Integer
+			 * </p>
+			 */
+			public final static String ALARM_TYPE = DATA3;
+		}
+
+	}
+
+
+	private static synchronized UriFactory getUriFactory(String authority)
+	{
+		UriFactory uriFactory = sUriFactories.get(authority);
+		if (uriFactory == null)
+		{
+			uriFactory = new UriFactory(authority);
+			uriFactory.addUri(TaskLists.CONTENT_URI_PATH);
+			uriFactory.addUri(Tasks.CONTENT_URI_PATH);
+			uriFactory.addUri(Tasks.SEARCH_URI_PATH);
+			uriFactory.addUri(Instances.CONTENT_URI_PATH);
+			uriFactory.addUri(Categories.CONTENT_URI_PATH);
+			uriFactory.addUri(Alarms.CONTENT_URI_PATH);
+			uriFactory.addUri(Properties.CONTENT_URI_PATH);
+			sUriFactories.put(authority, uriFactory);
+
+		}
+		return uriFactory;
+	}
+}
diff --git a/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java b/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java
deleted file mode 120000
index f77e8c16..00000000
--- a/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java
+++ /dev/null
@@ -1 +0,0 @@
-/home/rfc2822/Entwicklung/Android/task-provider/src/org/dmfs/provider/tasks/UriFactory.java
\ No newline at end of file
diff --git a/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java b/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java
new file mode 100644
index 00000000..2e330b6a
--- /dev/null
+++ b/app/src/main/java/org/dmfs/provider/tasks/UriFactory.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2014 Marten Gajda <marten@dmfs.org>
+ *
+ * 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.dmfs.provider.tasks;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import android.net.Uri;
+
+
+public class UriFactory
+{
+	public final String authority;
+
+	private final Map<String, Uri> mUriMap = new HashMap<String, Uri>(16);
+
+
+	UriFactory(String authority)
+	{
+		this.authority = authority;
+		mUriMap.put((String) null, Uri.parse("content://" + authority));
+	}
+
+
+	void addUri(String path)
+	{
+		mUriMap.put(path, Uri.parse("content://" + authority + "/" + path));
+	}
+
+
+	public Uri getUri()
+	{
+		return mUriMap.get(null);
+	}
+
+
+	public Uri getUri(String path)
+	{
+		return mUriMap.get(path);
+	}
+}
diff --git a/app/src/main/res/drawable-hdpi/tasks.png b/app/src/main/res/drawable-hdpi/tasks.png
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diff --git a/app/src/main/res/drawable-mdpi/tasks.png b/app/src/main/res/drawable-mdpi/tasks.png
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diff --git a/app/src/main/res/drawable-xhdpi/tasks.png b/app/src/main/res/drawable-xhdpi/tasks.png
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diff --git a/app/src/main/res/drawable-xxhdpi/tasks.png b/app/src/main/res/drawable-xxhdpi/tasks.png
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