001 /*
002 * Java Genetic Algorithm Library (jenetics-3.9.0).
003 * Copyright (c) 2007-2017 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@gmx.at)
019 */
020 package org.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 org.jenetics.internal.collection.Empty;
031 import org.jenetics.internal.util.require;
032
033 /**
034 * Immutable, ordered, fixed sized sequence.
035 *
036 * @see MSeq
037 *
038 * @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
039 * @since 1.0
040 * @version 3.6
041 */
042 public interface ISeq<T>
043 extends
044 Seq<T>,
045 Copyable<MSeq<T>>
046 {
047
048 @Override
049 public ISeq<T> subSeq(final int start, final int end);
050
051 @Override
052 public ISeq<T> subSeq(final int start);
053
054 @Override
055 public <B> ISeq<B> map(final Function<? super T, ? extends B> mapper);
056
057 @SuppressWarnings("unchecked")
058 @Override
059 public default ISeq<T> append(final T... values) {
060 return append(ISeq.of(values));
061 }
062
063 @Override
064 public ISeq<T> append(final Iterable<? extends T> values);
065
066 @SuppressWarnings("unchecked")
067 @Override
068 public default ISeq<T> prepend(final T... values) {
069 return prepend(ISeq.of(values));
070 }
071
072 @Override
073 public ISeq<T> prepend(final Iterable<? extends T> values);
074
075 /**
076 * Return a shallow copy of this sequence. The sequence elements are not
077 * cloned.
078 *
079 * @return a shallow copy of this sequence.
080 */
081 @Override
082 public MSeq<T> copy();
083
084
085 /* *************************************************************************
086 * Some static factory methods.
087 * ************************************************************************/
088
089 /**
090 * Single instance of an empty {@code ISeq}.
091 *
092 * @since 3.3
093 */
094 public static final ISeq<?> EMPTY = Empty.ISEQ;
095
096 /**
097 * Return an empty {@code ISeq}.
098 *
099 * @since 3.3
100 *
101 * @param <T> the element type of the returned {@code ISeq}.
102 * @return an empty {@code ISeq}.
103 */
104 public static <T> ISeq<T> empty() {
105 return Empty.iseq();
106 }
107
108 /**
109 * Returns a {@code Collector} that accumulates the input elements into a
110 * new {@code ISeq}.
111 *
112 * @param <T> the type of the input elements
113 * @return a {@code Collector} which collects all the input elements into an
114 * {@code ISeq}, in encounter order
115 */
116 public static <T> Collector<T, ?, ISeq<T>> toISeq() {
117 return Collector.of(
118 (Supplier<List<T>>)ArrayList::new,
119 List::add,
120 (left, right) -> { left.addAll(right); return left; },
121 ISeq::of
122 );
123 }
124
125 /**
126 * Create a new {@code ISeq} from the given values.
127 *
128 * @param <T> the element type
129 * @param values the array values.
130 * @return a new {@code ISeq} with the given values.
131 * @throws NullPointerException if the {@code values} array is {@code null}.
132 */
133 @SafeVarargs
134 public static <T> ISeq<T> of(final T... values) {
135 return values.length == 0
136 ? empty()
137 : MSeq.of(values).toISeq();
138 }
139
140 /**
141 * Create a new {@code ISeq} from the given values.
142 *
143 * @param <T> the element type
144 * @param values the array values.
145 * @return a new {@code ISeq} with the given values.
146 * @throws NullPointerException if the {@code values} array is {@code null}.
147 */
148 @SuppressWarnings("unchecked")
149 public static <T> ISeq<T> of(final Iterable<? extends T> values) {
150 requireNonNull(values);
151
152 return values instanceof ISeq<?>
153 ? (ISeq<T>)values
154 : values instanceof MSeq<?>
155 ? ((MSeq<T>)values).toISeq()
156 : MSeq.<T>of(values).toISeq();
157 }
158
159 // /**
160 // * Create a new {@code ISeq} instance from the remaining elements of the
161 // * given iterator.
162 // *
163 // * @since 3.3
164 // *
165 // * @param <T> the element type.
166 // * @return a new {@code ISeq} with the given remaining values.
167 // * @throws NullPointerException if the {@code values} object is
168 // * {@code null}.
169 // */
170 // public static <T> ISeq<T> of(final Iterator<? extends T> values) {
171 // final MSeq<T> seq = MSeq.of(values);
172 // return seq.isEmpty() ? empty() : seq.toISeq();
173 // }
174
175 /**
176 * Creates a new sequence, which is filled with objects created be the given
177 * {@code supplier}.
178 *
179 * @since 3.2
180 *
181 * @param <T> the element type of the sequence
182 * @param supplier the {@code Supplier} which creates the elements, the
183 * returned sequence is filled with
184 * @param length the length of the returned sequence
185 * @return a new sequence filled with elements given by the {@code supplier}
186 * @throws NegativeArraySizeException if the given {@code length} is
187 * negative
188 * @throws NullPointerException if the given {@code supplier} is
189 * {@code null}
190 */
191 public static <T> ISeq<T> of(
192 final Supplier<? extends T> supplier,
193 final int length
194 ) {
195 requireNonNull(supplier);
196 require.nonNegative(length);
197
198 return length == 0
199 ? empty()
200 : MSeq.<T>ofLength(length).fill(supplier).toISeq();
201 }
202
203 /**
204 * Allows a safe (without compile warning) upcast from {@code B} to
205 * {@code A}. Since {@code ISeq} instances are immutable, an <i>upcast</i>
206 * will be always safe.
207 *
208 * <pre>{@code
209 * // The sequence which we want to case.
210 * final ISeq<? extends Number> ints = ISeq.of(1, 2, 3, 4, 5);
211 *
212 * // This casts are possible without warning.
213 * final ISeq<Object> objects = ISeq.upcast(ints);
214 * final ISeq<Number> numbers = ISeq.upcast(ints);
215 *
216 * // This cast will, of course, still fail.
217 * final ISeq<String> strings = ISeq.upcast(ints);
218 * final ISeq<Integer> integers = ISeq.upcast(ints);
219 * }</pre>
220 *
221 * @since 3.6
222 *
223 * @param seq the sequence to cast safely
224 * @param <A> the <i>super</i>-object type
225 * @param <B> the <i>sub</i>-object type
226 * @return the casted instance of the given {@code seq}
227 */
228 @SuppressWarnings("unchecked")
229 public static <A, B extends A> ISeq<A> upcast(final ISeq<B> seq) {
230 return (ISeq<A>)seq;
231 }
232
233 }
|