ImmutableCollection (Eclipse Collections API

All Superinterfaces:

InternalIterable<T>, Iterable<T>, RichIterable<T>

All Known Subinterfaces:

ImmutableBag<T>, ImmutableBagIterable<T>, ImmutableList<T>, ImmutableSet<T>, ImmutableSetIterable<T>, ImmutableSortedBag<T>, ImmutableSortedSet<T>
```
public interface ImmutableCollection<T>
extends RichIterable<T>
```
ImmutableCollection is the common interface between ImmutableList, ImmutableSet and ImmutableBag. The ImmutableCollection interface is "contractually immutable" in that it does not have any mutating methods available on the public interface.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default <K,V> ImmutableMap<K,V>`	`aggregateBy(Function<? super T,? extends K> groupBy, Function0<? extends V> zeroValueFactory, Function2<? super V,? super T,? extends V> nonMutatingAggregator)` Applies an aggregate function over the iterable grouping results into a map based on the specific groupBy function.
`default <K,V> ImmutableMap<K,V>`	`aggregateInPlaceBy(Function<? super T,? extends K> groupBy, Function0<? extends V> zeroValueFactory, Procedure2<? super V,? super T> mutatingAggregator)` Applies an aggregate procedure over the iterable grouping results into a Map based on the specific groupBy function.
`Collection<T>`	`castToCollection()` This can be overridden in most implementations to just return this.
`<V> ImmutableCollection<V>`	`collect(Function<? super T,? extends V> function)` Returns a new collection with the results of applying the specified function on each element of the source collection.
`ImmutableBooleanCollection`	`collectBoolean(BooleanFunction<? super T> booleanFunction)` Returns a new primitive `boolean` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableByteCollection`	`collectByte(ByteFunction<? super T> byteFunction)` Returns a new primitive `byte` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableCharCollection`	`collectChar(CharFunction<? super T> charFunction)` Returns a new primitive `char` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableDoubleCollection`	`collectDouble(DoubleFunction<? super T> doubleFunction)` Returns a new primitive `double` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableFloatCollection`	`collectFloat(FloatFunction<? super T> floatFunction)` Returns a new primitive `float` iterable with the results of applying the specified function on each element of the source collection.
`<V> ImmutableCollection<V>`	`collectIf(Predicate<? super T> predicate, Function<? super T,? extends V> function)` Returns a new collection with the results of applying the specified function on each element of the source collection, but only for those elements which return true upon evaluation of the predicate.
`ImmutableIntCollection`	`collectInt(IntFunction<? super T> intFunction)` Returns a new primitive `int` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableLongCollection`	`collectLong(LongFunction<? super T> longFunction)` Returns a new primitive `long` iterable with the results of applying the specified function on each element of the source collection.
`ImmutableShortCollection`	`collectShort(ShortFunction<? super T> shortFunction)` Returns a new primitive `short` iterable with the results of applying the specified function on each element of the source collection.
`<P,V> ImmutableCollection<V>`	`collectWith(Function2<? super T,? super P,? extends V> function, P parameter)` Same as `RichIterable.collect(Function)` with a `Function2` and specified parameter which is passed to the block.
`default <V> ImmutableBag<V>`	`countBy(Function<? super T,? extends V> function)` This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
`default <V> ImmutableBag<V>`	`countByEach(Function<? super T,? extends Iterable<V>> function)` This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
`default <V,P> ImmutableBag<V>`	`countByWith(Function2<? super T,? super P,? extends V> function, P parameter)` This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
`<V> ImmutableCollection<V>`	`flatCollect(Function<? super T,? extends Iterable<V>> function)` `flatCollect` is a special case of `RichIterable.collect(Function)`.
`default <P,V> ImmutableCollection<V>`	`flatCollectWith(Function2<? super T,? super P,? extends Iterable<V>> function, P parameter)`
`<V> ImmutableMultimap<V,T>`	`groupBy(Function<? super T,? extends V> function)` For each element of the iterable, the function is evaluated and the results of these evaluations are collected into a new multimap, where the transformed value is the key and the original values are added to the same (or similar) species of collection as the source iterable.
`<V> ImmutableMultimap<V,T>`	`groupByEach(Function<? super T,? extends Iterable<V>> function)` Similar to `RichIterable.groupBy(Function)`, except the result of evaluating function will return a collection of keys for each value.
`default <V> ImmutableMap<V,T>`	`groupByUniqueKey(Function<? super T,? extends V> function)` For each element of the iterable, the function is evaluated, and the results of these evaluations are collected into a new map, where the transformed value is the key.
`ImmutableCollection<T>`	`newWith(T element)` This method is similar to the `with` method in `MutableCollection` with the difference that a new copy of this collection with the element appended will be returned.
`ImmutableCollection<T>`	`newWithAll(Iterable<? extends T> elements)` This method is similar to the `withAll` method in `MutableCollection` with the difference that a new copy of this collection with the elements appended will be returned.
`ImmutableCollection<T>`	`newWithout(T element)` This method is similar to the `without` method in `MutableCollection` with the difference that a new copy of this collection with the element removed will be returned.
`ImmutableCollection<T>`	`newWithoutAll(Iterable<? extends T> elements)` This method is similar to the `withoutAll` method in `MutableCollection` with the difference that a new copy of this collection with the elements removed will be returned.
`default Stream<T>`	`parallelStream()`
`PartitionImmutableCollection<T>`	`partition(Predicate<? super T> predicate)` Filters a collection into a PartitionedIterable based on the evaluation of the predicate.
`<P> PartitionImmutableCollection<T>`	`partitionWith(Predicate2<? super T,? super P> predicate, P parameter)` Filters a collection into a PartitionIterable based on the evaluation of the predicate.
`ImmutableCollection<T>`	`reject(Predicate<? super T> predicate)` Returns all elements of the source collection that return false when evaluating of the predicate.
`<P> ImmutableCollection<T>`	`rejectWith(Predicate2<? super T,? super P> predicate, P parameter)` Similar to `RichIterable.reject(Predicate)`, except with an evaluation parameter for the second generic argument in `Predicate2`.
`ImmutableCollection<T>`	`select(Predicate<? super T> predicate)` Returns all elements of the source collection that return true when evaluating the predicate.
`<S> ImmutableCollection<S>`	`selectInstancesOf(Class<S> clazz)` Returns all elements of the source collection that are instances of the Class `clazz`.
`<P> ImmutableCollection<T>`	`selectWith(Predicate2<? super T,? super P> predicate, P parameter)` Similar to `RichIterable.select(Predicate)`, except with an evaluation parameter for the second generic argument in `Predicate2`.
`default Spliterator<T>`	`spliterator()`
`default Stream<T>`	`stream()`
`<V> ImmutableObjectDoubleMap<V>`	`sumByDouble(Function<? super T,? extends V> groupBy, DoubleFunction<? super T> function)` Groups and sums the values using the two specified functions.
`<V> ImmutableObjectDoubleMap<V>`	`sumByFloat(Function<? super T,? extends V> groupBy, FloatFunction<? super T> function)` Groups and sums the values using the two specified functions.
`<V> ImmutableObjectLongMap<V>`	`sumByInt(Function<? super T,? extends V> groupBy, IntFunction<? super T> function)` Groups and sums the values using the two specified functions.
`<V> ImmutableObjectLongMap<V>`	`sumByLong(Function<? super T,? extends V> groupBy, LongFunction<? super T> function)` Groups and sums the values using the two specified functions.
`ImmutableCollection<T>`	`tap(Procedure<? super T> procedure)` Executes the Procedure for each element in the iterable and returns `this`.
`<S> ImmutableCollection<Pair<T,S>>`	`zip(Iterable<S> that)` Returns a `RichIterable` formed from this `RichIterable` and another `RichIterable` by combining corresponding elements in pairs.
`ImmutableCollection<Pair<T,Integer>>`	`zipWithIndex()` Zips this `RichIterable` with its indices.

Methods inherited from interface org.eclipse.collections.api.RichIterable
aggregateBy, allSatisfy, allSatisfyWith, anySatisfy, anySatisfyWith, appendString, appendString, appendString, asLazy, chunk, collect, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectIf, collectInt, collectLong, collectShort, collectWith, contains, containsAll, containsAllArguments, containsAllIterable, containsAny, containsAnyIterable, containsBy, containsNone, containsNoneIterable, count, countBy, countByEach, countByWith, countWith, detect, detectIfNone, detectOptional, detectWith, detectWithIfNone, detectWithOptional, each, flatCollect, flatCollectBoolean, flatCollectByte, flatCollectChar, flatCollectDouble, flatCollectFloat, flatCollectInt, flatCollectLong, flatCollectShort, flatCollectWith, forEach, getAny, getFirst, getLast, getOnly, groupBy, groupByAndCollect, groupByEach, groupByUniqueKey, injectInto, injectInto, injectInto, injectInto, injectInto, injectIntoDouble, injectIntoFloat, injectIntoInt, injectIntoLong, into, isEmpty, makeString, makeString, makeString, makeString, max, max, maxBy, maxByOptional, maxOptional, maxOptional, min, min, minBy, minByOptional, minOptional, minOptional, noneSatisfy, noneSatisfyWith, notEmpty, reduce, reduceInPlace, reduceInPlace, reject, rejectWith, select, selectWith, size, summarizeDouble, summarizeFloat, summarizeInt, summarizeLong, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toArray, toArray, toBag, toBiMap, toImmutableBag, toImmutableBiMap, toImmutableList, toImmutableMap, toImmutableSet, toImmutableSortedBag, toImmutableSortedBag, toImmutableSortedBagBy, toImmutableSortedList, toImmutableSortedList, toImmutableSortedListBy, toImmutableSortedSet, toImmutableSortedSet, toImmutableSortedSetBy, toList, toMap, toMap, toSet, toSortedBag, toSortedBag, toSortedBagBy, toSortedList, toSortedList, toSortedListBy, toSortedMap, toSortedMap, toSortedMapBy, toSortedSet, toSortedSet, toSortedSetBy, toString, zip, zipWithIndex

Methods inherited from interface org.eclipse.collections.api.InternalIterable
forEach, forEachWith, forEachWithIndex

Methods inherited from interface java.lang.Iterable
iterator

- Method Detail
  - newWith
```
ImmutableCollection<T> newWith(T element)
```
    This method is similar to the with method in MutableCollection with the difference that a new copy of this collection with the element appended will be returned.
  - newWithout
```
ImmutableCollection<T> newWithout(T element)
```
    This method is similar to the without method in MutableCollection with the difference that a new copy of this collection with the element removed will be returned.
  - newWithAll
```
ImmutableCollection<T> newWithAll(Iterable<? extends T> elements)
```
    This method is similar to the withAll method in MutableCollection with the difference that a new copy of this collection with the elements appended will be returned.
  - newWithoutAll
```
ImmutableCollection<T> newWithoutAll(Iterable<? extends T> elements)
```
    This method is similar to the withoutAll method in MutableCollection with the difference that a new copy of this collection with the elements removed will be returned.
  - tap
```
ImmutableCollection<T> tap(Procedure<? super T> procedure)
```
    Description copied from interface: RichIterable
    Executes the Procedure for each element in the iterable and returns this.
    Example using a Java 8 lambda expression:
```
 RichIterable<Person> tapped =
     people.tap(person -> LOGGER.info(person.getName()));
 
```
    Specified by:
    
    tap in interface RichIterable<T>
    
    See Also:
    
    RichIterable.each(Procedure), RichIterable.forEach(Procedure)
  - select
```
ImmutableCollection<T> select(Predicate<? super T> predicate)
```
    Description copied from interface: RichIterable
    Returns all elements of the source collection that return true when evaluating the predicate. This method is also commonly called filter.
    Example using a Java 8 lambda expression:
```
 RichIterable<Person> selected =
     people.select(person -> person.getAddress().getCity().equals("London"));
 
```
    Specified by:
    
    select in interface RichIterable<T>
  - selectWith
```
<P> ImmutableCollection<T> selectWith(Predicate2<? super T,? super P> predicate,
                                      P parameter)
```
    Description copied from interface: RichIterable
    Similar to RichIterable.select(Predicate), except with an evaluation parameter for the second generic argument in Predicate2.
    E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years
    Example using a Java 8 lambda expression:
```
 RichIterable<Person> selected =
     people.selectWith((Person person, Integer age) -> person.getAge()>= age, Integer.valueOf(18));
 
```
    Specified by:
    
    selectWith in interface RichIterable<T>
    
    Parameters:
    
    predicate - a Predicate2 to use as the select criteria
    
    parameter - a parameter to pass in for evaluation of the second argument P in predicate
    
    See Also:
    
    RichIterable.select(Predicate)
  - reject
```
ImmutableCollection<T> reject(Predicate<? super T> predicate)
```
    Description copied from interface: RichIterable
    Returns all elements of the source collection that return false when evaluating of the predicate. This method is also sometimes called filterNot and is the equivalent of calling iterable.select(Predicates.not(predicate)).
    Example using a Java 8 lambda expression:
```
 RichIterable<Person> rejected =
     people.reject(person -> person.person.getLastName().equals("Smith"));
 
```
    Specified by:
    
    reject in interface RichIterable<T>
    
    Parameters:
    
    predicate - a Predicate to use as the reject criteria
    
    Returns:
    
    a RichIterable that contains elements that cause Predicate.accept(Object) method to evaluate to false
  - rejectWith
```
<P> ImmutableCollection<T> rejectWith(Predicate2<? super T,? super P> predicate,
                                      P parameter)
```
    Description copied from interface: RichIterable
    Similar to RichIterable.reject(Predicate), except with an evaluation parameter for the second generic argument in Predicate2.
    E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years
    Example using a Java 8 lambda expression:
```
 RichIterable<Person> rejected =
     people.rejectWith((Person person, Integer age) -> person.getAge() < age, Integer.valueOf(18));
 
```
    Specified by:
    
    rejectWith in interface RichIterable<T>
    
    Parameters:
    
    predicate - a Predicate2 to use as the select criteria
    
    parameter - a parameter to pass in for evaluation of the second argument P in predicate
    
    See Also:
    
    RichIterable.select(Predicate)
  - partition
```
PartitionImmutableCollection<T> partition(Predicate<? super T> predicate)
```
    Description copied from interface: RichIterable
    Filters a collection into a PartitionedIterable based on the evaluation of the predicate.
    Example using a Java 8 lambda expression:
```
 PartitionIterable<Person> newYorkersAndNonNewYorkers =
     people.partition(person -> person.getAddress().getState().getName().equals("New York"));
 
```
    Specified by:
    
    partition in interface RichIterable<T>
  - partitionWith
```
<P> PartitionImmutableCollection<T> partitionWith(Predicate2<? super T,? super P> predicate,
                                                  P parameter)
```
    Description copied from interface: RichIterable
    Filters a collection into a PartitionIterable based on the evaluation of the predicate.
    Example using a Java 8 lambda expression:
```
 PartitionIterable<Person> newYorkersAndNonNewYorkers =
     people.partitionWith((Person person, String state) -> person.getAddress().getState().getName().equals(state), "New York");
 
```
    Specified by:
    
    partitionWith in interface RichIterable<T>
  - selectInstancesOf
```
<S> ImmutableCollection<S> selectInstancesOf(Class<S> clazz)
```
    Description copied from interface: RichIterable
    Returns all elements of the source collection that are instances of the Class clazz.
```
 RichIterable<Integer> integers =
     List.mutable.with(new Integer(0), new Long(0L), new Double(0.0)).selectInstancesOf(Integer.class);
 
```
    Specified by:
    
    selectInstancesOf in interface RichIterable<T>
  - collect
```
<V> ImmutableCollection<V> collect(Function<? super T,? extends V> function)
```
    Description copied from interface: RichIterable
    Returns a new collection with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 RichIterable<String> names =
     people.collect(person -> person.getFirstName() + " " + person.getLastName());
 
```
    Specified by:
    
    collect in interface RichIterable<T>
  - collectBoolean
```
ImmutableBooleanCollection collectBoolean(BooleanFunction<? super T> booleanFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive boolean iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 BooleanIterable licenses =
     people.collectBoolean(person -> person.hasDrivingLicense());
 
```
    Specified by:
    
    collectBoolean in interface RichIterable<T>
  - collectByte
```
ImmutableByteCollection collectByte(ByteFunction<? super T> byteFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive byte iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 ByteIterable bytes =
     people.collectByte(person -> person.getCode());
 
```
    Specified by:
    
    collectByte in interface RichIterable<T>
  - collectChar
```
ImmutableCharCollection collectChar(CharFunction<? super T> charFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive char iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 CharIterable chars =
     people.collectChar(person -> person.getMiddleInitial());
 
```
    Specified by:
    
    collectChar in interface RichIterable<T>
  - collectDouble
```
ImmutableDoubleCollection collectDouble(DoubleFunction<? super T> doubleFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive double iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 DoubleIterable doubles =
     people.collectDouble(person -> person.getMilesFromNorthPole());
 
```
    Specified by:
    
    collectDouble in interface RichIterable<T>
  - collectFloat
```
ImmutableFloatCollection collectFloat(FloatFunction<? super T> floatFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive float iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 FloatIterable floats =
     people.collectFloat(person -> person.getHeightInInches());
 
```
    Specified by:
    
    collectFloat in interface RichIterable<T>
  - collectInt
```
ImmutableIntCollection collectInt(IntFunction<? super T> intFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive int iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 IntIterable ints =
     people.collectInt(person -> person.getAge());
 
```
    Specified by:
    
    collectInt in interface RichIterable<T>
  - collectLong
```
ImmutableLongCollection collectLong(LongFunction<? super T> longFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive long iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 LongIterable longs =
     people.collectLong(person -> person.getGuid());
 
```
    Specified by:
    
    collectLong in interface RichIterable<T>
  - collectShort
```
ImmutableShortCollection collectShort(ShortFunction<? super T> shortFunction)
```
    Description copied from interface: RichIterable
    Returns a new primitive short iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.
    Example using a Java 8 lambda expression:
```
 ShortIterable shorts =
     people.collectShort(person -> person.getNumberOfJunkMailItemsReceivedPerMonth());
 
```
    Specified by:
    
    collectShort in interface RichIterable<T>
  - collectWith
```
<P,V> ImmutableCollection<V> collectWith(Function2<? super T,? super P,? extends V> function,
                                         P parameter)
```
    Description copied from interface: RichIterable
    Same as RichIterable.collect(Function) with a Function2 and specified parameter which is passed to the block.
    Example using a Java 8 lambda expression:
```
 RichIterable<Integer> integers =
     Lists.mutable.with(1, 2, 3).collectWith((each, parameter) -> each + parameter, Integer.valueOf(1));
 
```
    Specified by:
    
    collectWith in interface RichIterable<T>
    
    Parameters:
    
    function - A Function2 to use as the collect transformation function
    
    parameter - A parameter to pass in for evaluation of the second argument P in function
    
    Returns:
    
    A new RichIterable that contains the transformed elements returned by Function2.value(Object, Object)
    
    See Also:
    
    RichIterable.collect(Function)
  - collectIf
```
<V> ImmutableCollection<V> collectIf(Predicate<? super T> predicate,
                                     Function<? super T,? extends V> function)
```
    Description copied from interface: RichIterable
    Returns a new collection with the results of applying the specified function on each element of the source collection, but only for those elements which return true upon evaluation of the predicate. This is the optimized equivalent of calling iterable.select(predicate).collect(function).
    Example using a Java 8 lambda and method reference:
```
 RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(e -> e != null, Object::toString);
 
```
    Example using Predicates factory:
```
 RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(Predicates.notNull(), Functions.getToString());
 
```
    Specified by:
    
    collectIf in interface RichIterable<T>
  - flatCollect
```
<V> ImmutableCollection<V> flatCollect(Function<? super T,? extends Iterable<V>> function)
```
    Description copied from interface: RichIterable
    flatCollect is a special case of RichIterable.collect(Function). With collect, when the Function returns a collection, the result is a collection of collections. flatCollect outputs a single "flattened" collection instead. This method is commonly called flatMap.
    Consider the following example where we have a Person class, and each Person has a list of Address objects. Take the following Function:
```
 Function<Person, List<Address>> addressFunction = Person::getAddresses;
 RichIterable<Person> people = ...;
 
```
    Using collect returns a collection of collections of addresses.
```
 RichIterable<List<Address>> addresses = people.collect(addressFunction);
 
```
    Using flatCollect returns a single flattened list of addresses.
```
 RichIterable<Address> addresses = people.flatCollect(addressFunction);
 
```
    Specified by:
    
    flatCollect in interface RichIterable<T>
    
    Parameters:
    
    function - The Function to apply
    
    Returns:
    
    a new flattened collection produced by applying the given function
  - flatCollectWith
```
default <P,V> ImmutableCollection<V> flatCollectWith(Function2<? super T,? super P,? extends Iterable<V>> function,
                                                     P parameter)
```
    Specified by:
    
    flatCollectWith in interface RichIterable<T>
    
    Since:
    
    9.2
  - sumByInt
```
<V> ImmutableObjectLongMap<V> sumByInt(Function<? super T,? extends V> groupBy,
                                       IntFunction<? super T> function)
```
    Description copied from interface: RichIterable
    
    Groups and sums the values using the two specified functions.
    
    Specified by:
    
    sumByInt in interface RichIterable<T>
  - sumByFloat
```
<V> ImmutableObjectDoubleMap<V> sumByFloat(Function<? super T,? extends V> groupBy,
                                           FloatFunction<? super T> function)
```
    Description copied from interface: RichIterable
    
    Groups and sums the values using the two specified functions.
    
    Specified by:
    
    sumByFloat in interface RichIterable<T>
  - sumByLong
```
<V> ImmutableObjectLongMap<V> sumByLong(Function<? super T,? extends V> groupBy,
                                        LongFunction<? super T> function)
```
    Description copied from interface: RichIterable
    
    Groups and sums the values using the two specified functions.
    
    Specified by:
    
    sumByLong in interface RichIterable<T>
  - sumByDouble
```
<V> ImmutableObjectDoubleMap<V> sumByDouble(Function<? super T,? extends V> groupBy,
                                            DoubleFunction<? super T> function)
```
    Description copied from interface: RichIterable
    
    Groups and sums the values using the two specified functions.
    
    Specified by:
    
    sumByDouble in interface RichIterable<T>
  - countBy
```
default <V> ImmutableBag<V> countBy(Function<? super T,? extends V> function)
```
    Description copied from interface: RichIterable
    
    This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
    
    Specified by:
    
    countBy in interface RichIterable<T>
    
    Since:
    
    9.0
  - countByWith
```
default <V,P> ImmutableBag<V> countByWith(Function2<? super T,? super P,? extends V> function,
                                          P parameter)
```
    Description copied from interface: RichIterable
    
    This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
    
    Specified by:
    
    countByWith in interface RichIterable<T>
    
    Since:
    
    9.0
  - countByEach
```
default <V> ImmutableBag<V> countByEach(Function<? super T,? extends Iterable<V>> function)
```
    Description copied from interface: RichIterable
    
    This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
    
    Specified by:
    
    countByEach in interface RichIterable<T>
    
    Since:
    
    10.0.0
  - groupBy
```
<V> ImmutableMultimap<V,T> groupBy(Function<? super T,? extends V> function)
```
    Description copied from interface: RichIterable
    For each element of the iterable, the function is evaluated and the results of these evaluations are collected into a new multimap, where the transformed value is the key and the original values are added to the same (or similar) species of collection as the source iterable.
    Example using a Java 8 method reference:
```
 Multimap<String, Person> peopleByLastName =
     people.groupBy(Person::getLastName);
 
```
    Specified by:
    
    groupBy in interface RichIterable<T>
  - groupByEach
```
<V> ImmutableMultimap<V,T> groupByEach(Function<? super T,? extends Iterable<V>> function)
```
    Description copied from interface: RichIterable
    
    Similar to RichIterable.groupBy(Function), except the result of evaluating function will return a collection of keys for each value.
    
    Specified by:
    
    groupByEach in interface RichIterable<T>
  - groupByUniqueKey
```
default <V> ImmutableMap<V,T> groupByUniqueKey(Function<? super T,? extends V> function)
```
    Description copied from interface: RichIterable
    
    For each element of the iterable, the function is evaluated, and the results of these evaluations are collected into a new map, where the transformed value is the key. The generated keys must each be unique, or else an exception is thrown.
    
    Specified by:
    
    groupByUniqueKey in interface RichIterable<T>
    
    See Also:
    
    RichIterable.groupBy(Function)
  - zip
```
<S> ImmutableCollection<Pair<T,S>> zip(Iterable<S> that)
```
    Description copied from interface: RichIterable
    
    Returns a RichIterable formed from this RichIterable and another RichIterable by combining corresponding elements in pairs. If one of the two RichIterables is longer than the other, its remaining elements are ignored.
    
    Specified by:
    
    zip in interface RichIterable<T>
    
    Type Parameters:
    
    S - the type of the second half of the returned pairs
    
    Parameters:
    
    that - The RichIterable providing the second half of each result pair
    
    Returns:
    
    A new RichIterable containing pairs consisting of corresponding elements of this RichIterable and that. The length of the returned RichIterable is the minimum of the lengths of this RichIterable and that.
  - zipWithIndex
```
ImmutableCollection<Pair<T,Integer>> zipWithIndex()
```
    Description copied from interface: RichIterable
    
    Zips this RichIterable with its indices.
    
    Specified by:
    
    zipWithIndex in interface RichIterable<T>
    
    Returns:
    
    A new RichIterable containing pairs consisting of all elements of this RichIterable paired with their index. Indices start at 0.
    
    See Also:
    
    RichIterable.zip(Iterable)
  - aggregateInPlaceBy
```
default <K,V> ImmutableMap<K,V> aggregateInPlaceBy(Function<? super T,? extends K> groupBy,
                                                   Function0<? extends V> zeroValueFactory,
                                                   Procedure2<? super V,? super T> mutatingAggregator)
```
    Description copied from interface: RichIterable
    
    Applies an aggregate procedure over the iterable grouping results into a Map based on the specific groupBy function. Aggregate results are required to be mutable as they will be changed in place by the procedure. A second function specifies the initial "zero" aggregate value to work with (i.e. new AtomicInteger(0)).
    
    Specified by:
    
    aggregateInPlaceBy in interface RichIterable<T>
  - aggregateBy
```
default <K,V> ImmutableMap<K,V> aggregateBy(Function<? super T,? extends K> groupBy,
                                            Function0<? extends V> zeroValueFactory,
                                            Function2<? super V,? super T,? extends V> nonMutatingAggregator)
```
    Description copied from interface: RichIterable
    
    Applies an aggregate function over the iterable grouping results into a map based on the specific groupBy function. Aggregate results are allowed to be immutable as they will be replaced in place in the map. A second function specifies the initial "zero" aggregate value to work with (i.e. Integer.valueOf(0)).
    
    Specified by:
    
    aggregateBy in interface RichIterable<T>
  - stream
```
default Stream<T> stream()
```
    Since:
    
    9.0
  - parallelStream
```
default Stream<T> parallelStream()
```
    Since:
    
    9.0
  - spliterator
```
default Spliterator<T> spliterator()
```
    Specified by:
    
    spliterator in interface Iterable<T>
    
    Since:
    
    9.0
  - castToCollection
```
Collection<T> castToCollection()
```
    This can be overridden in most implementations to just return this.
    
    Since:
    
    9.0

Interface ImmutableCollection<T>

Method Summary

Methods inherited from interface org.eclipse.collections.api.RichIterable

Methods inherited from interface org.eclipse.collections.api.InternalIterable

Methods inherited from interface java.lang.Iterable

Method Detail

newWith

newWithout

newWithAll

newWithoutAll

tap

select

selectWith

reject

rejectWith

partition

partitionWith

selectInstancesOf

collect

collectBoolean

collectByte

collectChar

collectDouble

collectFloat

collectInt

collectLong

collectShort

collectWith

collectIf

flatCollect

flatCollectWith

sumByInt

sumByFloat

sumByLong

sumByDouble

countBy

countByWith

countByEach

groupBy

groupByEach

groupByUniqueKey

zip

zipWithIndex

aggregateInPlaceBy

aggregateBy

stream

parallelStream

spliterator

castToCollection