Dart Documentationclean_dataExceptedDataSetView

ExceptedDataSetView class

Represents a read-only data set that is a result of an minus operation of two sets.

class ExceptedDataSetView extends FilteredDataSetBase {

 /**
  * Creates a new data set from [source1] and [source2] only with elements that appear in A but not B.
  */
 ExceptedDataSetView(DataSetView source1,
     DataSetView source2): super([source1, source2]);

 bool _shouldContain(dataObj) =>
   sources[0].contains(dataObj) && !sources[1].contains(dataObj);


}

Extends

DataSetView > TransformedDataSet > FilteredDataSetBase > ExceptedDataSetView

Constructors

new ExceptedDataSetView(DataSetView source1, DataSetView source2) #

Creates a new data set from source1 and source2 only with elements that appear in A but not B.

ExceptedDataSetView(DataSetView source1,
   DataSetView source2): super([source1, source2]);

Properties

final E first #

mixed in from IterableMixin

Returns the first element.

If this is empty throws a StateError. Otherwise this method is equivalent to this.elementAt(0)

docs inherited from Iterable<E>
E get first {
 Iterator it = iterator;
 if (!it.moveNext()) {
   throw new StateError("No elements");
 }
 return it.current;
}

final bool isEmpty #

mixed in from IterableMixin

Returns true if there is no element in this collection.

docs inherited from Iterable<E>
bool get isEmpty => !iterator.moveNext();

final bool isNotEmpty #

mixed in from IterableMixin

Returns true if there is at least one element in this collection.

docs inherited from Iterable<E>
bool get isNotEmpty => !isEmpty;

final Iterator iterator #

inherited from DataSetView

Returns an Iterator that iterates over this Iterable object.

docs inherited from Iterable
Iterator get iterator => _data.iterator;

final E last #

mixed in from IterableMixin

Returns the last element.

If this is empty throws a StateError.

docs inherited from Iterable<E>
E get last {
 Iterator it = iterator;
 if (!it.moveNext()) {
   throw new StateError("No elements");
 }
 E result;
 do {
   result = it.current;
 } while(it.moveNext());
 return result;
}

final int length #

inherited from DataSetView

Returns the number of elements in this.

Counting all elements may be involve running through all elements and can therefore be slow.

docs inherited from Iterable
int get length => _data.length;

final Stream<dynamic> onBeforeAdd #

Stream populated with DataMapView events before any data object is added.

Stream<dynamic> get onBeforeAdd {
 if(_onBeforeAddedController == null) {
   _onBeforeAddedController =
       new StreamController.broadcast(sync: true);
 }
 return _onBeforeAddedController.stream;
}

final Stream<dynamic> onBeforeRemove #

Stream populated with DataMapView events before any data object is removed.

Stream<dynamic> get onBeforeRemove {
 if(_onBeforeRemovedController == null) {
   _onBeforeRemovedController =
       new StreamController.broadcast(sync: true);
 }
 return _onBeforeRemovedController.stream;
}

final Stream<ChangeSet> onChange #

Stream populated with ChangeSet events whenever the collection or any of data object contained gets changed.

Stream<ChangeSet> get onChange {
 if(_onChangeController == null) {
   _onChangeController =
       new StreamController.broadcast();
 }
 return _onChangeController.stream;
}

final Stream<Map> onChangeSync #

Stream populated with {'change': ChangeSet, 'author': dynamic} events synchronously at the moment when the collection or any data object contained gets changed.

Stream<Map> get onChangeSync => _onChangeSyncController.stream;

final E single #

mixed in from IterableMixin

Returns the single element in this.

If this is empty or has more than one element throws a StateError.

docs inherited from Iterable<E>
E get single {
 Iterator it = iterator;
 if (!it.moveNext()) throw new StateError("No elements");
 E result = it.current;
 if (it.moveNext()) throw new StateError("More than one element");
 return result;
}

List<dynamic> sources #

mixed in from TransformedDataBase

The source ChangeNotificationsMixin this collection is derived from.

List<dynamic> sources

final StreamController_onBeforeAddedController #

inherited from DataSetView
final StreamController_onBeforeAddedController =
   new StreamController.broadcast(sync: true)

Methods

void addIndex([Iterable<String> indexedProps]) #

inherited from DataSetView

Adds indices on chosen properties. Indexed properties can be used to retrieve data by their value with the findBy method, or removed by their value with the removeBy method.

void addIndex([Iterable<String> indexedProps]) {

 if (indexedProps != null) {
   // initialize change listener; lazy
   if (_index.keys.length == 0) {
      _initIndexListener();
   }

   for (String prop in indexedProps) {
     if (!_index.containsKey(prop)) {
       // create and initialize the index
       _index[prop] = new HashIndex();
       _rebuildIndex(prop);
     }
   }
 }
}

bool any(bool f(E element)) #

mixed in from IterableMixin

Returns true if one element of this collection satisfies the predicate test. Returns false otherwise.

docs inherited from Iterable<E>
bool any(bool f(E element)) {
 for (E element in this) {
   if (f(element)) return true;
 }
 return false;
}

bool contains(dataObj) #

inherited from DataSetView

Returns true iff this set contains the given dataObj.

@param dataObj Data object to be searched for.

bool contains(dataObj) => _data.contains(dataObj);

void dispose() #

inherited from TransformedDataSet

Stream all new changes marked in ChangeSet.

docs inherited from DataSetView
void dispose() {
 _sourcesSubscription.forEach((subscription) => subscription.cancel());
 super.dispose();
}

E elementAt(int index) #

mixed in from IterableMixin

Returns the indexth element.

If this has fewer than index elements throws a RangeError.

Note: if this does not have a deterministic iteration order then the function may simply return any element without any iteration if there are at least index elements in this.

docs inherited from Iterable<E>
E elementAt(int index) {
 if (index is! int || index < 0) throw new RangeError.value(index);
 int remaining = index;
 for (E element in this) {
   if (remaining == 0) return element;
   remaining--;
 }
 throw new RangeError.value(index);
}

bool every(bool f(E element)) #

mixed in from IterableMixin

Returns true if every elements of this collection satisify the predicate test. Returns false otherwise.

docs inherited from Iterable<E>
bool every(bool f(E element)) {
 for (E element in this) {
   if (!f(element)) return false;
 }
 return true;
}

Iterable expand(Iterable f(E element)) #

mixed in from IterableMixin

Expands each element of this Iterable into zero or more elements.

The resulting Iterable runs through the elements returned by f for each element of this, in order.

The returned Iterable is lazy, and calls f for each element of this every time it's iterated.

docs inherited from Iterable<E>
Iterable expand(Iterable f(E element)) =>
   new ExpandIterable<E, dynamic>(this, f);

Iterable<DataMapView> findBy(String property, value) #

inherited from DataSetView

Finds all objects that have property equal to value in this set.

Iterable<DataMapView> findBy(String property, dynamic value) {
 if (!_index.containsKey(property)) {
   throw new NoIndexException('Property $property is not indexed.');
 }
 return _index[property][value];
}

dynamic firstWhere(bool test(E value), {Object orElse()}) #

mixed in from IterableMixin

Returns the first element that satisfies the given predicate test.

If none matches, the result of invoking the orElse function is returned. By default, when orElse is null, a StateError is thrown.

docs inherited from Iterable<E>
dynamic firstWhere(bool test(E value), { Object orElse() }) {
 for (E element in this) {
   if (test(element)) return element;
 }
 if (orElse != null) return orElse();
 throw new StateError("No matching element");
}

dynamic fold(initialValue, combine(previousValue, E element)) #

mixed in from IterableMixin

Reduces a collection to a single value by iteratively combining each element of the collection with an existing value using the provided function.

Use initialValue as the initial value, and the function combine to create a new value from the previous one and an element.

Example of calculating the sum of an iterable:

iterable.fold(0, (prev, element) => prev + element);
docs inherited from Iterable<E>
dynamic fold(var initialValue,
            dynamic combine(var previousValue, E element)) {
 var value = initialValue;
 for (E element in this) value = combine(value, element);
 return value;
}

void forEach(void f(E element)) #

mixed in from IterableMixin

Applies the function f to each element of this collection.

docs inherited from Iterable<E>
void forEach(void f(E element)) {
 for (E element in this) f(element);
}

String join([String separator = ""]) #

mixed in from IterableMixin

Converts each element to a String and concatenates the strings.

Converts each element to a String by calling Object.toString on it. Then concatenates the strings, optionally separated by the separator string.

docs inherited from Iterable<E>
String join([String separator = ""]) {
 Iterator<E> iterator = this.iterator;
 if (!iterator.moveNext()) return "";
 StringBuffer buffer = new StringBuffer();
 if (separator == null || separator == "") {
   do {
     buffer.write("${iterator.current}");
   } while (iterator.moveNext());
 } else {
   buffer.write("${iterator.current}");
   while (iterator.moveNext()) {
     buffer.write(separator);
     buffer.write("${iterator.current}");
   }
 }
 return buffer.toString();
}

dynamic lastWhere(bool test(E value), {Object orElse()}) #

mixed in from IterableMixin

Returns the last element that satisfies the given predicate test.

If none matches, the result of invoking the orElse function is returned. By default, when orElse is null, a StateError is thrown.

docs inherited from Iterable<E>
dynamic lastWhere(bool test(E value), { Object orElse() }) {
 E result = null;
 bool foundMatching = false;
 for (E element in this) {
   if (test(element)) {
     result = element;
     foundMatching = true;
   }
 }
 if (foundMatching) return result;
 if (orElse != null) return orElse();
 throw new StateError("No matching element");
}

DataSetView liveDifference(DataSetView other) #

inherited from DataSetView

Minuses the data set with another DataSetView to form a new, ExceptedDataSetView.

The set remains up-to-date w.r.t. to the source set via background synchronization.

DataSetView liveDifference(DataSetView other) {
 return new ExceptedDataSetView(this, other);
}

DataSetView liveIntersection(DataSetView other) #

inherited from DataSetView

Intersects the data set with another DataSetView to form a new, IntersectedSetView.

The set remains up-to-date w.r.t. to the source set via background synchronization.

DataSetView liveIntersection(DataSetView other) {
 return other == this
     ? this
         : new IntersectedDataSetView(this, other);
}

DataListView liveSort(int compare(a, b)) #

inherited from DataSetView

Sorts the data set with the given compare function.

DataListView liveSort(int compare(a, b)) {
 return new SortedDataListView(this, compare);
}

DataListView liveSortByKey(key(x)) #

inherited from DataSetView

Sorts the data set by comparing keys generated by key function.

DataListView liveSortByKey(key(x)) {
 return new SortedDataListView.fromKey(this, key);
}

DataSetView liveUnion(DataSetView other) #

inherited from DataSetView

Unions the data set with another DataSetView to form a new, UnionedSetView.

The set remains up-to-date w.r.t. to the source set via background synchronization.

DataSetView liveUnion(DataSetView other) {
 return other == this
     ? this
         : new UnionedDataSetView(this, other);
}

DataSetView liveWhere(test, [ChangeNotificationsMixin args = null]) #

inherited from DataSetView

Filters the data set w.r.t. the given filter function test.

The set remains up-to-date w.r.t. to the source set via background synchronization.

DataSetView liveWhere(test, [ChangeNotificationsMixin args = null]) {
 return new FilteredDataSetView(this, test, args);
}

Iterable map(f(E element)) #

mixed in from IterableMixin

Returns a lazy Iterable where each element e of this is replaced by the result of f(e).

This method returns a view of the mapped elements. As long as the returned Iterable is not iterated over, the supplied function f will not be invoked. The transformed elements will not be cached. Iterating multiple times over the the returned Iterable will invoke the supplied function f multiple times on the same element.

docs inherited from Iterable<E>
Iterable map(f(E element)) => new MappedIterable<E, dynamic>(this, f);

E reduce(E combine(E value, E element)) #

mixed in from IterableMixin

Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.

Example of calculating the sum of an iterable:

iterable.reduce((value, element) => value + element);
docs inherited from Iterable<E>
E reduce(E combine(E value, E element)) {
 Iterator<E> iterator = this.iterator;
 if (!iterator.moveNext()) {
   throw new StateError("No elements");
 }
 E value = iterator.current;
 while (iterator.moveNext()) {
   value = combine(value, iterator.current);
 }
 return value;
}

E singleWhere(bool test(E value)) #

mixed in from IterableMixin

Returns the single element that satisfies test. If no or more than one element match then a StateError is thrown.

docs inherited from Iterable<E>
E singleWhere(bool test(E value)) {
 E result = null;
 bool foundMatching = false;
 for (E element in this) {
   if (test(element)) {
     if (foundMatching) {
       throw new StateError("More than one matching element");
     }
     result = element;
     foundMatching = true;
   }
 }
 if (foundMatching) return result;
 throw new StateError("No matching element");
}

Iterable<E> skip(int n) #

mixed in from IterableMixin

Returns an Iterable that skips the first n elements.

If this has fewer than n elements, then the resulting Iterable is empty.

It is an error if n is negative.

docs inherited from Iterable<E>
Iterable<E> skip(int n) {
 return new SkipIterable<E>(this, n);
}

Iterable<E> skipWhile(bool test(E value)) #

mixed in from IterableMixin

Returns an Iterable that skips elements while test is satisfied.

The filtering happens lazily. Every new Iterator of the returned Iterable iterates over all elements of this.

As long as the iterator's elements satisfy test they are discarded. Once an element does not satisfy the test the iterator stops testing and uses every later element unconditionally. That is, the elements of the returned Iterable are the elements of this starting from the first element that does not satisfy test.

docs inherited from Iterable<E>
Iterable<E> skipWhile(bool test(E value)) {
 return new SkipWhileIterable<E>(this, test);
}

Iterable<E> take(int n) #

mixed in from IterableMixin

Returns an Iterable with at most n elements.

The returned Iterable may contain fewer than n elements, if this contains fewer than n elements.

It is an error if n is negative.

docs inherited from Iterable<E>
Iterable<E> take(int n) {
 return new TakeIterable<E>(this, n);
}

Iterable<E> takeWhile(bool test(E value)) #

mixed in from IterableMixin

Returns an Iterable that stops once test is not satisfied anymore.

The filtering happens lazily. Every new Iterator of the returned Iterable starts iterating over the elements of this.

When the iterator encounters an element e that does not satisfy test, it discards e and moves into the finished state. That is, it does not get or provide any more elements.

docs inherited from Iterable<E>
Iterable<E> takeWhile(bool test(E value)) {
 return new TakeWhileIterable<E>(this, test);
}

List<E> toList({bool growable: true}) #

mixed in from IterableMixin

Creates a List containing the elements of this Iterable.

The elements are in iteration order. The list is fixed-length if growable is false.

docs inherited from Iterable<E>
List<E> toList({ bool growable: true }) =>
   new List<E>.from(this, growable: growable);

Set<E> toSet() #

mixed in from IterableMixin

Creates a Set containing the elements of this Iterable.

docs inherited from Iterable<E>
Set<E> toSet() => new Set<E>.from(this);

String toString() #

inherited from DataSetView

Returns a string representation of this object.

docs inherited from Object
String toString() => toList().toString();

void unattachListeners() #

inherited from DataSetView
void unattachListeners() {
 _onChangeController.close();
}

Iterable<E> where(bool f(E element)) #

mixed in from IterableMixin

Returns a lazy Iterable with all elements that satisfy the predicate test.

This method returns a view of the mapped elements. As long as the returned Iterable is not iterated over, the supplied function test will not be invoked. Iterating will not cache results, and thus iterating multiple times over the returned Iterable will invoke the supplied function test multiple times on the same element.

docs inherited from Iterable<E>
Iterable<E> where(bool f(E element)) => new WhereIterable<E>(this, f);