001 /*
002 * Java Genetic Algorithm Library (jenetics-5.1.0).
003 * Copyright (c) 2007-2019 Franz Wilhelmstötter
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 * Author:
018 * Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
019 */
020 package io.jenetics.util;
021
022 import static java.util.Objects.requireNonNull;
023
024 import java.util.ArrayList;
025 import java.util.List;
026 import java.util.function.Function;
027 import java.util.function.Supplier;
028 import java.util.stream.Collector;
029
030 import io.jenetics.internal.collection.Empty;
031 import io.jenetics.internal.collection.Empty.EmptyISeq;
032 import io.jenetics.internal.util.require;
033
034 /**
035 * Immutable, ordered, fixed sized sequence.
036 *
037 * @see MSeq
038 *
039 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
040 * @since 1.0
041 * @version 4.2
042 */
043 public interface ISeq<T>
044 extends
045 Seq<T>,
046 Copyable<MSeq<T>>
047 {
048
049 @Override
050 public ISeq<T> subSeq(final int start, final int end);
051
052 @Override
053 public ISeq<T> subSeq(final int start);
054
055 @Override
056 public <B> ISeq<B> map(final Function<? super T, ? extends B> mapper);
057
058 @SuppressWarnings("unchecked")
059 @Override
060 public default ISeq<T> append(final T... values) {
061 return append(ISeq.of(values));
062 }
063
064 @Override
065 public ISeq<T> append(final Iterable<? extends T> values);
066
067 @SuppressWarnings("unchecked")
068 @Override
069 public default ISeq<T> prepend(final T... values) {
070 return prepend(ISeq.of(values));
071 }
072
073 @Override
074 public ISeq<T> prepend(final Iterable<? extends T> values);
075
076 /**
077 * Return a shallow copy of this sequence. The sequence elements are not
078 * cloned.
079 *
080 * @return a shallow copy of this sequence.
081 */
082 @Override
083 public MSeq<T> copy();
084
085
086 /* *************************************************************************
087 * Some static helper methods.
088 * ************************************************************************/
089
090 /**
091 * Return a sequence whose elements are all the elements of the first
092 * element followed by all the elements of the sequence.
093 *
094 * @since 5.0
095 *
096 * @param a the first element
097 * @param b the appending sequence
098 * @param <T> the type of the sequence elements
099 * @return the concatenation of the two inputs
100 * @throws NullPointerException if one of the second arguments is
101 * {@code null}
102 */
103 @SuppressWarnings("unchecked")
104 public static <T> ISeq<T> concat(
105 final T a,
106 final ISeq<? extends T> b
107 ) {
108 return ((ISeq<T>)b).prepend(a);
109 }
110
111 /**
112 * Return a sequence whose elements are all the elements of the first
113 * sequence followed by all the elements of the vararg array.
114 *
115 * @since 5.0
116 *
117 * @param a the first sequence
118 * @param b the vararg elements
119 * @param <T> the type of the sequence elements
120 * @return the concatenation of the two inputs
121 * @throws NullPointerException if one of the arguments is {@code null}
122 */
123 @SuppressWarnings("unchecked")
124 public static <T> ISeq<T> concat(
125 final ISeq<? extends T> a,
126 final T... b
127 ) {
128 return ((ISeq<T>)a).append(b);
129 }
130
131 /**
132 * Return a sequence whose elements are all the elements of the first
133 * sequence followed by all the elements of the second sequence.
134 *
135 * @since 5.0
136 *
137 * @param a the first sequence
138 * @param b the second sequence
139 * @param <T> the type of the sequence elements
140 * @return the concatenation of the two input sequences
141 * @throws NullPointerException if one of the arguments is {@code null}
142 */
143 @SuppressWarnings("unchecked")
144 public static <T> ISeq<T> concat(
145 final ISeq<? extends T> a,
146 final ISeq<? extends T> b
147 ) {
148 return ((ISeq<T>)a).append(b);
149 }
150
151 /* *************************************************************************
152 * Some static factory methods.
153 * ************************************************************************/
154
155 /**
156 * Single instance of an empty {@code ISeq}.
157 *
158 * @since 3.3
159 */
160 public static final ISeq<?> EMPTY = EmptyISeq.INSTANCE;
161
162 /**
163 * Return an empty {@code ISeq}.
164 *
165 * @since 3.3
166 *
167 * @param <T> the element type of the returned {@code ISeq}.
168 * @return an empty {@code ISeq}.
169 */
170 public static <T> ISeq<T> empty() {
171 return Empty.iseq();
172 }
173
174 /**
175 * Returns a {@code Collector} that accumulates the input elements into a
176 * new {@code ISeq}.
177 *
178 * @param <T> the type of the input elements
179 * @return a {@code Collector} which collects all the input elements into an
180 * {@code ISeq}, in encounter order
181 */
182 public static <T> Collector<T, ?, ISeq<T>> toISeq() {
183 return Collector.of(
184 (Supplier<List<T>>)ArrayList::new,
185 List::add,
186 (left, right) -> { left.addAll(right); return left; },
187 ISeq::of
188 );
189 }
190
191 /**
192 * Returns a {@code Collector} that accumulates the last {@code n} input
193 * elements into a new {@code ISeq}.
194 *
195 * @since 5.0
196 *
197 * @param maxSize the maximal size of the collected sequence
198 * @param <T> the type of the input elements
199 * @return a {@code Collector} which collects maximal {@code maxSize} of the
200 * input elements into an {@code ISeq}, in encounter order
201 * @throws IllegalArgumentException if the {@code maxSize} is negative
202 */
203 public static <T> Collector<T, ?, ISeq<T>> toISeq(final int maxSize) {
204 return Seqs.toSeq(maxSize, Buffer::toSeq);
205 }
206
207 /**
208 * Create a new {@code ISeq} from the given values.
209 *
210 * @param <T> the element type
211 * @param values the array values.
212 * @return a new {@code ISeq} with the given values.
213 * @throws NullPointerException if the {@code values} array is {@code null}.
214 */
215 @SafeVarargs
216 public static <T> ISeq<T> of(final T... values) {
217 return values.length == 0
218 ? empty()
219 : MSeq.of(values).toISeq();
220 }
221
222 /**
223 * Create a new {@code ISeq} from the given values.
224 *
225 * @param <T> the element type
226 * @param values the array values.
227 * @return a new {@code ISeq} with the given values.
228 * @throws NullPointerException if the {@code values} array is {@code null}.
229 */
230 @SuppressWarnings("unchecked")
231 public static <T> ISeq<T> of(final Iterable<? extends T> values) {
232 requireNonNull(values);
233
234 return values instanceof ISeq
235 ? (ISeq<T>)values
236 : values instanceof MSeq
237 ? ((MSeq<T>)values).toISeq()
238 : MSeq.<T>of(values).toISeq();
239 }
240
241 // /**
242 // * Create a new {@code ISeq} instance from the remaining elements of the
243 // * given iterator.
244 // *
245 // * @since 3.3
246 // *
247 // * @param <T> the element type.
248 // * @return a new {@code ISeq} with the given remaining values.
249 // * @throws NullPointerException if the {@code values} object is
250 // * {@code null}.
251 // */
252 // public static <T> ISeq<T> of(final Iterator<? extends T> values) {
253 // final MSeq<T> seq = MSeq.of(values);
254 // return seq.isEmpty() ? empty() : seq.toISeq();
255 // }
256
257 /**
258 * Creates a new sequence, which is filled with objects created be the given
259 * {@code supplier}.
260 *
261 * @since 3.2
262 *
263 * @param <T> the element type of the sequence
264 * @param supplier the {@code Supplier} which creates the elements, the
265 * returned sequence is filled with
266 * @param length the length of the returned sequence
267 * @return a new sequence filled with elements given by the {@code supplier}
268 * @throws NegativeArraySizeException if the given {@code length} is
269 * negative
270 * @throws NullPointerException if the given {@code supplier} is
271 * {@code null}
272 */
273 public static <T> ISeq<T> of(
274 final Supplier<? extends T> supplier,
275 final int length
276 ) {
277 requireNonNull(supplier);
278 require.nonNegative(length);
279
280 return length == 0
281 ? empty()
282 : MSeq.<T>ofLength(length).fill(supplier).toISeq();
283 }
284
285 /**
286 * Allows a safe (without compile warning) upcast from {@code B} to
287 * {@code A}. Since {@code ISeq} instances are immutable, an <i>upcast</i>
288 * will be always safe.
289 *
290 * <pre>{@code
291 * // The sequence which we want to case.
292 * final ISeq<? extends Number> ints = ISeq.of(1, 2, 3, 4, 5);
293 *
294 * // This casts are possible without warning.
295 * final ISeq<Object> objects = ISeq.upcast(ints);
296 * final ISeq<Number> numbers = ISeq.upcast(ints);
297 *
298 * // This cast will, of course, still fail.
299 * final ISeq<String> strings = ISeq.upcast(ints);
300 * final ISeq<Integer> integers = ISeq.upcast(ints);
301 * }</pre>
302 *
303 * @since 3.6
304 *
305 * @param seq the sequence to cast safely
306 * @param <A> the <i>super</i>-object type
307 * @param <B> the <i>sub</i>-object type
308 * @return the casted instance of the given {@code seq}
309 */
310 @SuppressWarnings("unchecked")
311 public static <A, B extends A> ISeq<A> upcast(final ISeq<B> seq) {
312 return (ISeq<A>)seq;
313 }
314
315 }
|