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/*
* Copyright (C) 2002-2024 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.chars;
import java.util.Collection;
import static it.unimi.dsi.fastutil.Size64.sizeOf;
import it.unimi.dsi.fastutil.ints.IntIterator;
import it.unimi.dsi.fastutil.ints.IntSpliterator;
/**
* A type-specific {@link Collection}; provides some additional methods that use polymorphism to
* avoid (un)boxing.
*
*
* Additionally, this class defines strengthens (again) {@link #iterator()}.
*
*
* This interface specifies reference equality semantics (members will be compared equal with
* {@code ==} instead of {@link Object#equals(Object) equals}), which may result in breaks in
* contract if attempted to be used with non reference-equality semantics based {@link Collection}s.
* For example, a {@code aReferenceCollection.equals(aObjectCollection)} may return different a
* different result then {@code aObjectCollection.equals(aReferenceCollection)}, in violation of
* {@link Object#equals equals}'s contract requiring it being symmetric.
*
* @see Collection
*/
public interface CharCollection extends Collection, CharIterable {
/**
* Returns a type-specific iterator on the elements of this collection.
*
* @apiNote This specification strengthens the one given in {@link java.lang.Iterable#iterator()},
* which was already strengthened in the corresponding type-specific class, but was
* weakened by the fact that this interface extends {@link Collection}.
*
* @return a type-specific iterator on the elements of this collection.
*/
@Override
CharIterator iterator();
/**
* Returns a widened primitive iterator on the elements of this collection.
*
*
*
* This method is provided for the purpose of APIs that expect only the JDK's primitive iterators,
* of which there are only {@code int}, {@code long}, and {@code double}.
*
*
* WARNING: This is not the same as converting the source to a sequence of code
* points. This returned instance literally performs {@code (int)(charValue)} casts. Surrogate pairs
* will be left as separate elements instead of combined into a single element with the code point
* it represents. See {@link Character} for more discussion on code points, char values, and
* surrogate pairs.
*
* @return a widened primitive iterator on the elements of this collection.
* @since 8.5.0
*/
@Override
default IntIterator intIterator() {
return CharIterable.super.intIterator();
}
// If you change these default spliterator methods, you will likely need to update Iterable, List,
// Set, and SortedSet too
/**
* Returns a type-specific spliterator on the elements of this collection.
*
*
* See {@link java.util.Collection#spliterator()} for more documentation on the requirements of the
* returned spliterator.
*
* @apiNote This specification strengthens the one given in
* {@link java.util.Collection#spliterator()}.
*
* Also, this is generally the only {@code spliterator} method subclasses should override.
*
* @implSpec The default implementation returns a late-binding spliterator (see
* {@link java.util.Spliterator Spliterator} for documentation on what binding policies
* mean) that wraps this instance's type specific {@link #iterator}.
*
* Additionally, it reports {@link java.util.Spliterator#SIZED Spliterator.SIZED}
*
* @implNote As this default implementation wraps the iterator, and {@link java.util.Iterator} is an
* inherently linear API, the returned spliterator will yield limited performance gains
* when run in parallel contexts, as the returned spliterator's
* {@link java.util.Spliterator#trySplit() trySplit()} will have linear runtime.
*
* @return a type-specific spliterator on the elements of this collection.
* @since 8.5.0
*/
@Override
default CharSpliterator spliterator() {
return CharSpliterators.asSpliterator(iterator(), sizeOf(this), CharSpliterators.COLLECTION_SPLITERATOR_CHARACTERISTICS);
}
/**
* Returns widened primitive spliterator on the elements of this collection.
*
*
*
* This method is provided for the purpose of APIs that expect only the JDK's primitive
* spliterators, of which there are only {@code int}, {@code long}, and {@code double}.
*
*
* WARNING: This is not the same as converting the source to a sequence of code
* points. This returned instance literally performs {@code (int)(charValue)} casts. Surrogate pairs
* will be left as separate elements instead of combined into a single element with the code point
* it represents. See {@link Character} for more discussion on code points, char values, and
* surrogate pairs.
*
* @return a widened primitive spliterator on the elements of this collection.
* @since 8.5.0
*/
@Override
default IntSpliterator intSpliterator() {
return CharIterable.super.intSpliterator();
}
/**
* Ensures that this collection contains the specified element (optional operation).
*
* @see Collection#add(Object)
*/
boolean add(char key);
/**
* Returns {@code true} if this collection contains the specified element.
*
* @see Collection#contains(Object)
*/
boolean contains(char key);
/**
* Removes a single instance of the specified element from this collection, if it is present
* (optional operation).
*
*
* Note that this method should be called {@link java.util.Collection#remove(Object) remove()}, but
* the clash with the similarly named index-based method in the {@link java.util.List} interface
* forces us to use a distinguished name. For simplicity, the set interfaces reinstates
* {@code remove()}.
*
* @see Collection#remove(Object)
*/
boolean rem(char key);
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default boolean add(final Character key) {
return add((key).charValue());
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default boolean contains(final Object key) {
if (key == null) return false;
return contains(((Character)(key)).charValue());
}
/**
* {@inheritDoc}
*
* @deprecated Please use (and implement) the {@code rem()} method instead.
*/
@Deprecated
@Override
default boolean remove(final Object key) {
if (key == null) return false;
return rem(((Character)(key)).charValue());
}
/**
* Returns a primitive type array containing the items of this collection.
*
* @return a primitive type array containing the items of this collection.
* @see Collection#toArray()
*/
char[] toCharArray();
/**
* Returns a primitive type array containing the items of this collection.
*
*
* Note that, contrarily to {@link Collection#toArray(Object[])}, this methods just writes all
* elements of this collection: no special value will be added after the last one.
*
* @param a if this array is big enough, it will be used to store this collection.
* @return a primitive type array containing the items of this collection.
* @see Collection#toArray(Object[])
* @deprecated Please use {@code toArray()} instead—this method is redundant and will be
* removed in the future.
*/
@Deprecated
default char[] toCharArray(char a[]) {
return toArray(a);
}
/**
* Returns an array containing all of the elements in this collection; the runtime type of the
* returned array is that of the specified array.
*
*
* Note that, contrarily to {@link Collection#toArray(Object[])}, this methods just writes all
* elements of this collection: no special value will be added after the last one.
*
* @param a if this array is big enough, it will be used to store this collection.
* @return a primitive type array containing the items of this collection.
* @see Collection#toArray(Object[])
*/
char[] toArray(char a[]);
/**
* Adds all elements of the given type-specific collection to this collection.
*
* @param c a type-specific collection.
* @see Collection#addAll(Collection)
* @return {@code true} if this collection changed as a result of the call.
*/
boolean addAll(CharCollection c);
/**
* Checks whether this collection contains all elements from the given type-specific collection.
*
* @param c a type-specific collection.
* @see Collection#containsAll(Collection)
* @return {@code true} if this collection contains all elements of the argument.
*/
boolean containsAll(CharCollection c);
/**
* Remove from this collection all elements in the given type-specific collection.
*
* @param c a type-specific collection.
* @see Collection#removeAll(Collection)
* @return {@code true} if this collection changed as a result of the call.
*/
boolean removeAll(CharCollection c);
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default boolean removeIf(final java.util.function.Predicate filter) {
return removeIf(filter instanceof CharPredicate ? ((CharPredicate)filter) : (CharPredicate)key -> filter.test(Character.valueOf(it.unimi.dsi.fastutil.SafeMath.safeIntToChar(key))));
}
/**
* Remove from this collection all elements which satisfy the given predicate.
*
* @param filter a predicate which returns {@code true} for elements to be removed.
* @see Collection#removeIf(java.util.function.Predicate)
* @return {@code true} if any elements were removed.
* @apiNote Implementing classes should generally override this method, and take the default
* implementation of the other overloads which will delegate to this method (after proper
* conversions).
*/
default boolean removeIf(final CharPredicate filter) {
java.util.Objects.requireNonNull(filter);
boolean removed = false;
final CharIterator each = iterator();
while (each.hasNext()) {
if (filter.test(each.nextChar())) {
each.remove();
removed = true;
}
}
return removed;
}
/**
* Remove from this collection all elements which satisfy the given predicate.
*
* @param filter a predicate which returns {@code true} for elements to be removed.
* @see Collection#removeIf(java.util.function.Predicate)
* @return {@code true} if any elements were removed.
* @implNote Unless the argument is type-specific, this method will introduce an intermediary lambda
* to perform widening casts. Please use the type-specific overload to avoid this
* overhead.
*/
@SuppressWarnings("overloads")
default boolean removeIf(final java.util.function.IntPredicate filter) {
return removeIf(filter instanceof CharPredicate ? (CharPredicate)filter : (CharPredicate)filter::test);
}
/**
* Retains in this collection only elements from the given type-specific collection.
*
* @param c a type-specific collection.
* @see Collection#retainAll(Collection)
* @return {@code true} if this collection changed as a result of the call.
*/
boolean retainAll(CharCollection c);
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default java.util.stream.Stream stream() {
return Collection.super.stream();
}
/**
* Return a primitive stream over the elements, performing widening casts if needed.
*
*
* WARNING: This is not the same as converting the source to a sequence of code
* points. This returned instance literally performs {@code (int)(charValue)} casts. Surrogate pairs
* will be left as separate elements instead of combined into a single element with the code point
* it represents. See {@link Character} for more discussion on code points, char values, and
* surrogate pairs.
*
* @return a primitive stream over the elements.
* @see Collection#stream()
* @see java.util.stream.IntStream
*/
default java.util.stream.IntStream intStream() {
return java.util.stream.StreamSupport.intStream(intSpliterator(), false);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default java.util.stream.Stream parallelStream() {
return Collection.super.parallelStream();
}
/**
* Return a parallel primitive stream over the elements, performing widening casts if needed.
*
*
* WARNING: This is not the same as converting the source to a sequence of code
* points. This returned instance literally performs {@code (int)(charValue)} casts. Surrogate pairs
* will be left as separate elements instead of combined into a single element with the code point
* it represents. See {@link Character} for more discussion on code points, char values, and
* surrogate pairs.
*
* @return a parallel primitive stream over the elements.
* @see Collection#parallelStream()
* @see java.util.stream.IntStream
*/
default java.util.stream.IntStream intParallelStream() {
return java.util.stream.StreamSupport.intStream(intSpliterator(), true);
}
}