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src/java.base/share/classes/java/lang/Iterable.java

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   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.lang;
  26 
  27 import java.util.Iterator;
  28 import java.util.Objects;
  29 import java.util.Spliterator;
  30 import java.util.Spliterators;
  31 import java.util.function.Consumer;
  32 
  33 /**
  34  * Implementing this interface allows an object to be the target of
  35  * the "for-each loop" statement. See
  36  * <strong>
  37  * <a href="{@docRoot}/../technotes/guides/language/foreach.html">For-each Loop</a>
  38  * </strong>
  39  *
  40  * @param <T> the type of elements returned by the iterator
  41  *
  42  * @since 1.5
  43  * @jls 14.14.2 The enhanced for statement
  44  */
  45 public interface Iterable<T> {
  46     /**
  47      * Returns an iterator over elements of type {@code T}.
  48      *
  49      * @return an Iterator.
  50      */
  51     Iterator<T> iterator();
  52 
  53     /**
  54      * Performs the given action for each element of the {@code Iterable}
  55      * until all elements have been processed or the action throws an
  56      * exception.  Unless otherwise specified by the implementing class,
  57      * actions are performed in the order of iteration (if an iteration order
  58      * is specified).  Exceptions thrown by the action are relayed to the
  59      * caller.
  60      *
  61      * @implSpec
  62      * <p>The default implementation behaves as if:
  63      * <pre>{@code
  64      *     for (T t : this)
  65      *         action.accept(t);
  66      * }</pre>
  67      *
  68      * @param action The action to be performed for each element
  69      * @throws NullPointerException if the specified action is null
  70      * @since 1.8
  71      */
  72     default void forEach(Consumer<? super T> action) {
  73         Objects.requireNonNull(action);
  74         for (T t : this) {
  75             action.accept(t);




  76         }
  77     }
  78 
  79     /**
  80      * Creates a {@link Spliterator} over the elements described by this
  81      * {@code Iterable}.
  82      *
  83      * @implSpec
  84      * The default implementation creates an
  85      * <em><a href="../util/Spliterator.html#binding">early-binding</a></em>
  86      * spliterator from the iterable's {@code Iterator}.  The spliterator
  87      * inherits the <em>fail-fast</em> properties of the iterable's iterator.
  88      *
  89      * @implNote
  90      * The default implementation should usually be overridden.  The
  91      * spliterator returned by the default implementation has poor splitting
  92      * capabilities, is unsized, and does not report any spliterator
  93      * characteristics. Implementing classes can nearly always provide a
  94      * better implementation.
  95      *
  96      * @return a {@code Spliterator} over the elements described by this
  97      * {@code Iterable}.
  98      * @since 1.8
  99      */
 100     default Spliterator<T> spliterator() {
 101         return Spliterators.spliteratorUnknownSize(iterator(), 0);
 102     }
 103 }


   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package javany.lang;
  26 
  27 import javany.util.Iterator;
  28 import java.util.Objects;
  29 //import java.util.Spliterator;
  30 //import java.util.Spliterators;
  31 import javany.util.function.Consumer;
  32 
  33 /**
  34  * Implementing this interface allows an object to be the target of
  35  * the "for-each loop" statement. See
  36  * <strong>
  37  * <a href="{@docRoot}/../technotes/guides/language/foreach.html">For-each Loop</a>
  38  * </strong>
  39  *
  40  * @param <T> the type of elements returned by the iterator
  41  *
  42  * @since 1.5
  43  * @jls 14.14.2 The enhanced for statement
  44  */
  45 public interface Iterable<any T> {
  46     /**
  47      * Returns an iterator over elements of type {@code T}.
  48      *
  49      * @return an Iterator.
  50      */
  51     Iterator<T> iterator();
  52 
  53     /**
  54      * Performs the given action for each element of the {@code Iterable}
  55      * until all elements have been processed or the action throws an
  56      * exception.  Unless otherwise specified by the implementing class,
  57      * actions are performed in the order of iteration (if an iteration order
  58      * is specified).  Exceptions thrown by the action are relayed to the
  59      * caller.
  60      *
  61      * @implSpec
  62      * <p>The default implementation behaves as if:
  63      * <pre>{@code
  64      *     for (T t : this)
  65      *         action.accept(t);
  66      * }</pre>
  67      *
  68      * @param action The action to be performed for each element
  69      * @throws NullPointerException if the specified action is null
  70      * @since 1.8
  71      */
  72     default void forEach(Consumer<? super T> action) {
  73         Objects.requireNonNull(action);
  74 //        for (T t : this) {
  75 //            action.accept(t);
  76 //        }
  77         Iterator<T> iterator = iterator();
  78         while (iterator.hasNext()) {
  79             action.accept(iterator.next());
  80         }
  81     }
  82 
  83     /**
  84      * Creates a {@link Spliterator} over the elements described by this
  85      * {@code Iterable}.
  86      *
  87      * @implSpec
  88      * The default implementation creates an
  89      * <em><a href="../util/Spliterator.html#binding">early-binding</a></em>
  90      * spliterator from the iterable's {@code Iterator}.  The spliterator
  91      * inherits the <em>fail-fast</em> properties of the iterable's iterator.
  92      *
  93      * @implNote
  94      * The default implementation should usually be overridden.  The
  95      * spliterator returned by the default implementation has poor splitting
  96      * capabilities, is unsized, and does not report any spliterator
  97      * characteristics. Implementing classes can nearly always provide a
  98      * better implementation.
  99      *
 100      * @return a {@code Spliterator} over the elements described by this
 101      * {@code Iterable}.
 102      * @since 1.8
 103      */
 104 //    default Spliterator<T> spliterator() {
 105 //        return Spliterators.spliteratorUnknownSize(iterator(), 0);
 106 //    }
 107 }
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