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feature: Added ObservableProperty and ObservableList

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MikeMitterer committed Nov 2, 2018
1 parent 6e0f459 commit 7e0120ac086b20f9560c52f8843ba4cbc96517e4
Showing with 650 additions and 0 deletions.
  1. +357 −0 lib/observable/ObservableList.dart
  2. +273 −0 lib/observable/ObservableProperty.dart
  3. +20 −0 test/unit/observable/Observable_test.dart
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/*
* Copyright (c) 2015, Michael Mitterer (office@mikemitterer.at),
* IT-Consulting and Development Limited.
*
* All Rights Reserved.
*
* 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.
*/

part of m4d_core;

enum ListChangeType {
ADD, INSERT, UPDATE, REMOVE, CLEAR
}

typedef bool UpdateItem<T>(final dom.HtmlElement element, final T item);

/// Propagated if List changes
class ListChangedEvent<T> {
/// [changetype] shows what changed
final ListChangeType changetype;

/// [item] is set on ADD, REMOVE and UPDATE
final T item;

/// [prevItem] is set on UPDATE and defines the old Entry
/// It is also set on INSERT. It defines the previous items a the given index
final T prevItem;

/// Index in der Original-Liste (_innerList)
final int index;

ListChangedEvent(this.changetype,{ final T this.item, final this.prevItem, final this.index: -1 });
}

/// List that sends [ListChangeEvents] to the listener if this list changes
/// Supported methods:
/// Add, insert, update ([]), remove, clear, removeAll
///
/// @Component
/// class MyComponent extends MdlTemplateComponent {
///
/// final ObservableList<RecordsPerDay> records = new ObservableList<RecordsPerDay>(
/// updateCallback: _updateListItem);
///
/// void _init() {
///
/// render().then((_) {
/// _bindStoreActions();
/// });
/// }
///
/// void _bindStoreActions() {
/// if(_store == null) { return;}
///
/// _store.onChange.listen((final DataStoreChangedEvent event) {
/// _updateView();
/// });
/// }
///
/// void _updateView() {
///
/// if(records.length != _store.records.length) {
/// records.clear();
/// records.addAll(_store.records);
///
/// } else {
/// final List<RecordsPerDay> _storeRecords = _store.records;
/// for (int index = 0; index < _storeRecords.length; index++) {
///
/// // Triggers _updateListItem!!! in MaterialRepeat
/// records[index] = _storeRecords[index];
/// }
/// }
/// }
///
/// static bool _updateListItem(final dom.HtmlElement element, final RecordsPerDay item, final RecordsPerDay prevItem) {
/// if(element == null) {
/// return false;
/// }
/// final dom.SpanElement date = element.querySelector(".date");
/// final dom.SpanElement records = element.querySelector(".records");
/// date.text = item.date.toString();
/// records.text = item.records.toString();
/// return true;
/// }
///
/// @override
/// final String template = "...";
/// }
///
class ObservableList<T> extends ListBase<T> {
final Logger _logger = new Logger('mdlobservable.ObservableList');

final List<T> _innerList = new List();
final List<T> _filterBackup = new List();

StreamController<ListChangedEvent<T>> _onChange;

UpdateItem _updateCallback;

/// If [updateCallback] is given it will be called from [MaterialRepeat]
/// if the list updates
ObservableList({final UpdateItem updateCallback /*: _defaultUpdateCallback*/ })
: _updateCallback = updateCallback {
if(_updateCallback == null) {
_updateCallback = _defaultUpdateCallback;
}
}

/// Propagated Event-Listener
Stream<ListChangedEvent<T>> get onChange {
if(_onChange == null) {
_onChange = new StreamController<ListChangedEvent<T>>.broadcast(
onCancel: () => _onChange = null);
}
return _onChange.stream;
}

int get length => _innerList.length;

void set length(int length) {
_innerList.length = length;
}

/// Updates the internal List.
void operator []=(int index, T value) {
_fire(new ListChangedEvent<T>(ListChangeType.UPDATE,
item: value,
prevItem: _innerList[index],
index: index ));

_innerList[index] = value;
}

T operator [](int index) => _innerList[index];

void add(final T value) {
_innerList.add(value);

_fire(new ListChangedEvent<T>(
ListChangeType.ADD,
item: value,
index: _innerList.indexOf(value)));
}

void addAll(Iterable<T> all) {
_innerList.addAll(all);
all.forEach((final element) {
_fire(new ListChangedEvent<T>(
ListChangeType.ADD,
item: element,
index: _innerList.indexOf(element)));
});
}

void addIfAbsent(final T value) {
if(!_innerList.contains(value)) {
add(value);
}
}

@override
void insert(int index, T element) {
RangeError.checkValueInInterval(index, 0, length, "index");

if(index == _innerList.length) {
add(element);

} else {
if(index == 0) {

_fire(new ListChangedEvent<T>(
ListChangeType.INSERT,
item: element,
index: index ));

_innerList.insert(index,element);

} else {

_fire(new ListChangedEvent<T>(
ListChangeType.INSERT,
item: element,
prevItem: _innerList[index],
index: index));

_innerList.insert(index,element);
}
}
}

@override
void clear() {
_clearList();
_clearFilter();
}

@override
void removeRange(int start, int end) {
RangeError.checkValidRange(start, end, this.length);
for(int index = start;index < end;index++) {
_fire(new ListChangedEvent<T>(
ListChangeType.REMOVE,
item: _innerList[index],
index: index ));
}
_innerList.removeRange(start,end);
}

@override
bool remove(final Object element) {
_fire(new ListChangedEvent<T>(
ListChangeType.REMOVE,
item: element as T,
index: _innerList.indexOf(element as T) ));

return _innerList.remove(element);
}

@override
void removeWhere(bool test(final T element)) {
final List<T> itemsToRemove = new List<T>();

_innerList.forEach((final T element) {
if(test(element)) {
itemsToRemove.add(element);
}
});

itemsToRemove.forEach((final T element) => remove(element));
}

@override
void retainWhere(bool test(final T element)) {
final List<T> itemsToRemove = new List<T>();

_innerList.forEach((final T element) {
// remove items where test fails
if(test(element) == false) {
itemsToRemove.add(element);
}
});

itemsToRemove.forEach((final T element) => remove(element));
}

/// Filter items in list
///
/// final String text = filter.value.trim();
///
/// if(text.isNotEmpty) {
/// components.filter((final HackintoshComponent element) => element.name.contains(text));
/// } else {
/// components.resetFilter();
/// }
///
void filter(bool test(final T element)) {
if(_filterBackup.isEmpty) {
_filterBackup.addAll(_innerList);
}

_clearList();
addAll(_filterBackup.where(test));
}

/// Resets the item-List to it's original stand
void resetFilter() {
if(_filterBackup.isNotEmpty) {
_clearList();

addAll(_filterBackup);
_filterBackup.clear();
}
}

/// Called by MaterialRepeat do make fast updates
bool update(final dom.HtmlElement element, final T item)
=> _updateCallback(element,item);

/// ADD, INSERT, UPDATE, REMOVE, CLEAR
ObservableList<T> where(bool test(final T element)) {
_logger.info("Where called!!!!!!!!!!!!!!!");

final newList = new ObservableList<T>();
onChange.listen((final ListChangedEvent event) {
if(event.changetype != ListChangeType.CLEAR && test(event.item)) {
// ignore: missing_enum_constant_in_switch
switch(event.changetype) {
case ListChangeType.ADD:
newList.add(event.item);
break;
case ListChangeType.INSERT:
//newList.insert(event.index,event.item);
newList.add(event.item);

_logger.info("Items1: ${newList.length}");
break;
// case ListChangeType.UPDATE:
// if(newList.contains(event.item)) {
// //final index = newList.
// newList.update(event., item)
// }
// newList.add(event.item);
// break;
case ListChangeType.REMOVE:
newList.remove(event.item);
break;
}
}
if(event.changetype == ListChangeType.CLEAR) {
newList.clear();
}
});

return newList;
}

//- private -----------------------------------------------------------------------------------

void _fire(final ListChangedEvent<T> event) {
if( _onChange != null && _onChange.hasListener) {
_onChange.add(event);
}
}

/// Remove all items from list (DOM + innerList)
void _clearList() {
_fire(new ListChangedEvent<T>(ListChangeType.CLEAR));
_innerList.clear();
}

/// Remove items backed up items for filter
void _clearFilter() {
_filterBackup.clear();
}

/// Default Callback for updating the UI
///
/// It returns false which indicates that MaterialRepeater should call it's own
/// update routines
// @ToDo: https://github.com/dart-lang/sdk/issues/28996
static bool _defaultUpdateCallback/*<T>*/(final dom.HtmlElement element, final /* T */ item) {
return false;
}

}
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