feat(jdk8): move files to new folder to avoid resources compiled.

jdkSrc/jdk8/java/util/concurrent/ConcurrentMap.java

@@ -0,0 +1,517 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+package java.util.concurrent;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+/**
+ * A {@link java.util.Map} providing thread safety and atomicity
+ * guarantees.
+ *
+ * <p>Memory consistency effects: As with other concurrent
+ * collections, actions in a thread prior to placing an object into a
+ * {@code ConcurrentMap} as a key or value
+ * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
+ * actions subsequent to the access or removal of that object from
+ * the {@code ConcurrentMap} in another thread.
+ *
+ * <p>This interface is a member of the
+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ * @param <K> the type of keys maintained by this map
+ * @param <V> the type of mapped values
+ */
+public interface ConcurrentMap<K, V> extends Map<K, V> {
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implNote This implementation assumes that the ConcurrentMap cannot
+     * contain null values and {@code get()} returning null unambiguously means
+     * the key is absent. Implementations which support null values
+     * <strong>must</strong> override this default implementation.
+     *
+     * @throws ClassCastException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default V getOrDefault(Object key, V defaultValue) {
+        V v;
+        return ((v = get(key)) != null) ? v : defaultValue;
+    }
+
+   /**
+     * {@inheritDoc}
+     *
+     * @implSpec The default implementation is equivalent to, for this
+     * {@code map}:
+     * <pre> {@code
+     * for ((Map.Entry<K, V> entry : map.entrySet())
+     *     action.accept(entry.getKey(), entry.getValue());
+     * }</pre>
+     *
+     * @implNote The default implementation assumes that
+     * {@code IllegalStateException} thrown by {@code getKey()} or
+     * {@code getValue()} indicates that the entry has been removed and cannot
+     * be processed. Operation continues for subsequent entries.
+     *
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default void forEach(BiConsumer<? super K, ? super V> action) {
+        Objects.requireNonNull(action);
+        for (Map.Entry<K, V> entry : entrySet()) {
+            K k;
+            V v;
+            try {
+                k = entry.getKey();
+                v = entry.getValue();
+            } catch(IllegalStateException ise) {
+                // this usually means the entry is no longer in the map.
+                continue;
+            }
+            action.accept(k, v);
+        }
+    }
+
+    /**
+     * If the specified key is not already associated
+     * with a value, associate it with the given value.
+     * This is equivalent to
+     *  <pre> {@code
+     * if (!map.containsKey(key))
+     *   return map.put(key, value);
+     * else
+     *   return map.get(key);
+     * }</pre>
+     *
+     * except that the action is performed atomically.
+     *
+     * @implNote This implementation intentionally re-abstracts the
+     * inappropriate default provided in {@code Map}.
+     *
+     * @param key key with which the specified value is to be associated
+     * @param value value to be associated with the specified key
+     * @return the previous value associated with the specified key, or
+     *         {@code null} if there was no mapping for the key.
+     *         (A {@code null} return can also indicate that the map
+     *         previously associated {@code null} with the key,
+     *         if the implementation supports null values.)
+     * @throws UnsupportedOperationException if the {@code put} operation
+     *         is not supported by this map
+     * @throws ClassCastException if the class of the specified key or value
+     *         prevents it from being stored in this map
+     * @throws NullPointerException if the specified key or value is null,
+     *         and this map does not permit null keys or values
+     * @throws IllegalArgumentException if some property of the specified key
+     *         or value prevents it from being stored in this map
+     */
+     V putIfAbsent(K key, V value);
+
+    /**
+     * Removes the entry for a key only if currently mapped to a given value.
+     * This is equivalent to
+     *  <pre> {@code
+     * if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
+     *   map.remove(key);
+     *   return true;
+     * } else
+     *   return false;
+     * }</pre>
+     *
+     * except that the action is performed atomically.
+     *
+     * @implNote This implementation intentionally re-abstracts the
+     * inappropriate default provided in {@code Map}.
+     *
+     * @param key key with which the specified value is associated
+     * @param value value expected to be associated with the specified key
+     * @return {@code true} if the value was removed
+     * @throws UnsupportedOperationException if the {@code remove} operation
+     *         is not supported by this map
+     * @throws ClassCastException if the key or value is of an inappropriate
+     *         type for this map
+     *         (<a href="../Collection.html#optional-restrictions">optional</a>)
+     * @throws NullPointerException if the specified key or value is null,
+     *         and this map does not permit null keys or values
+     *         (<a href="../Collection.html#optional-restrictions">optional</a>)
+     */
+    boolean remove(Object key, Object value);
+
+    /**
+     * Replaces the entry for a key only if currently mapped to a given value.
+     * This is equivalent to
+     *  <pre> {@code
+     * if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) {
+     *   map.put(key, newValue);
+     *   return true;
+     * } else
+     *   return false;
+     * }</pre>
+     *
+     * except that the action is performed atomically.
+     *
+     * @implNote This implementation intentionally re-abstracts the
+     * inappropriate default provided in {@code Map}.
+     *
+     * @param key key with which the specified value is associated
+     * @param oldValue value expected to be associated with the specified key
+     * @param newValue value to be associated with the specified key
+     * @return {@code true} if the value was replaced
+     * @throws UnsupportedOperationException if the {@code put} operation
+     *         is not supported by this map
+     * @throws ClassCastException if the class of a specified key or value
+     *         prevents it from being stored in this map
+     * @throws NullPointerException if a specified key or value is null,
+     *         and this map does not permit null keys or values
+     * @throws IllegalArgumentException if some property of a specified key
+     *         or value prevents it from being stored in this map
+     */
+    boolean replace(K key, V oldValue, V newValue);
+
+    /**
+     * Replaces the entry for a key only if currently mapped to some value.
+     * This is equivalent to
+     *  <pre> {@code
+     * if (map.containsKey(key)) {
+     *   return map.put(key, value);
+     * } else
+     *   return null;
+     * }</pre>
+     *
+     * except that the action is performed atomically.
+     *
+     * @implNote This implementation intentionally re-abstracts the
+     * inappropriate default provided in {@code Map}.
+     *
+     * @param key key with which the specified value is associated
+     * @param value value to be associated with the specified key
+     * @return the previous value associated with the specified key, or
+     *         {@code null} if there was no mapping for the key.
+     *         (A {@code null} return can also indicate that the map
+     *         previously associated {@code null} with the key,
+     *         if the implementation supports null values.)
+     * @throws UnsupportedOperationException if the {@code put} operation
+     *         is not supported by this map
+     * @throws ClassCastException if the class of the specified key or value
+     *         prevents it from being stored in this map
+     * @throws NullPointerException if the specified key or value is null,
+     *         and this map does not permit null keys or values
+     * @throws IllegalArgumentException if some property of the specified key
+     *         or value prevents it from being stored in this map
+     */
+    V replace(K key, V value);
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec
+     * <p>The default implementation is equivalent to, for this {@code map}:
+     * <pre> {@code
+     * for ((Map.Entry<K, V> entry : map.entrySet())
+     *     do {
+     *        K k = entry.getKey();
+     *        V v = entry.getValue();
+     *     } while(!replace(k, v, function.apply(k, v)));
+     * }</pre>
+     *
+     * The default implementation may retry these steps when multiple
+     * threads attempt updates including potentially calling the function
+     * repeatedly for a given key.
+     *
+     * <p>This implementation assumes that the ConcurrentMap cannot contain null
+     * values and {@code get()} returning null unambiguously means the key is
+     * absent. Implementations which support null values <strong>must</strong>
+     * override this default implementation.
+     *
+     * @throws UnsupportedOperationException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @throws ClassCastException {@inheritDoc}
+     * @throws IllegalArgumentException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
+        Objects.requireNonNull(function);
+        forEach((k,v) -> {
+            while(!replace(k, v, function.apply(k, v))) {
+                // v changed or k is gone
+                if ( (v = get(k)) == null) {
+                    // k is no longer in the map.
+                    break;
+                }
+            }
+        });
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec
+     * The default implementation is equivalent to the following steps for this
+     * {@code map}, then returning the current value or {@code null} if now
+     * absent:
+     *
+     * <pre> {@code
+     * if (map.get(key) == null) {
+     *     V newValue = mappingFunction.apply(key);
+     *     if (newValue != null)
+     *         return map.putIfAbsent(key, newValue);
+     * }
+     * }</pre>
+     *
+     * The default implementation may retry these steps when multiple
+     * threads attempt updates including potentially calling the mapping
+     * function multiple times.
+     *
+     * <p>This implementation assumes that the ConcurrentMap cannot contain null
+     * values and {@code get()} returning null unambiguously means the key is
+     * absent. Implementations which support null values <strong>must</strong>
+     * override this default implementation.
+     *
+     * @throws UnsupportedOperationException {@inheritDoc}
+     * @throws ClassCastException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default V computeIfAbsent(K key,
+            Function<? super K, ? extends V> mappingFunction) {
+        Objects.requireNonNull(mappingFunction);
+        V v, newValue;
+        return ((v = get(key)) == null &&
+                (newValue = mappingFunction.apply(key)) != null &&
+                (v = putIfAbsent(key, newValue)) == null) ? newValue : v;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec
+     * The default implementation is equivalent to performing the following
+     * steps for this {@code map}, then returning the current value or
+     * {@code null} if now absent. :
+     *
+     * <pre> {@code
+     * if (map.get(key) != null) {
+     *     V oldValue = map.get(key);
+     *     V newValue = remappingFunction.apply(key, oldValue);
+     *     if (newValue != null)
+     *         map.replace(key, oldValue, newValue);
+     *     else
+     *         map.remove(key, oldValue);
+     * }
+     * }</pre>
+     *
+     * The default implementation may retry these steps when multiple threads
+     * attempt updates including potentially calling the remapping function
+     * multiple times.
+     *
+     * <p>This implementation assumes that the ConcurrentMap cannot contain null
+     * values and {@code get()} returning null unambiguously means the key is
+     * absent. Implementations which support null values <strong>must</strong>
+     * override this default implementation.
+     *
+     * @throws UnsupportedOperationException {@inheritDoc}
+     * @throws ClassCastException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default V computeIfPresent(K key,
+            BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+        Objects.requireNonNull(remappingFunction);
+        V oldValue;
+        while((oldValue = get(key)) != null) {
+            V newValue = remappingFunction.apply(key, oldValue);
+            if (newValue != null) {
+                if (replace(key, oldValue, newValue))
+                    return newValue;
+            } else if (remove(key, oldValue))
+               return null;
+        }
+        return oldValue;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec
+     * The default implementation is equivalent to performing the following
+     * steps for this {@code map}, then returning the current value or
+     * {@code null} if absent:
+     *
+     * <pre> {@code
+     * V oldValue = map.get(key);
+     * V newValue = remappingFunction.apply(key, oldValue);
+     * if (oldValue != null ) {
+     *    if (newValue != null)
+     *       map.replace(key, oldValue, newValue);
+     *    else
+     *       map.remove(key, oldValue);
+     * } else {
+     *    if (newValue != null)
+     *       map.putIfAbsent(key, newValue);
+     *    else
+     *       return null;
+     * }
+     * }</pre>
+     *
+     * The default implementation may retry these steps when multiple
+     * threads attempt updates including potentially calling the remapping
+     * function multiple times.
+     *
+     * <p>This implementation assumes that the ConcurrentMap cannot contain null
+     * values and {@code get()} returning null unambiguously means the key is
+     * absent. Implementations which support null values <strong>must</strong>
+     * override this default implementation.
+     *
+     * @throws UnsupportedOperationException {@inheritDoc}
+     * @throws ClassCastException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default V compute(K key,
+            BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+        Objects.requireNonNull(remappingFunction);
+        V oldValue = get(key);
+        for(;;) {
+            V newValue = remappingFunction.apply(key, oldValue);
+            if (newValue == null) {
+                // delete mapping
+                if (oldValue != null || containsKey(key)) {
+                    // something to remove
+                    if (remove(key, oldValue)) {
+                        // removed the old value as expected
+                        return null;
+                    }
+
+                    // some other value replaced old value. try again.
+                    oldValue = get(key);
+                } else {
+                    // nothing to do. Leave things as they were.
+                    return null;
+                }
+            } else {
+                // add or replace old mapping
+                if (oldValue != null) {
+                    // replace
+                    if (replace(key, oldValue, newValue)) {
+                        // replaced as expected.
+                        return newValue;
+                    }
+
+                    // some other value replaced old value. try again.
+                    oldValue = get(key);
+                } else {
+                    // add (replace if oldValue was null)
+                    if ((oldValue = putIfAbsent(key, newValue)) == null) {
+                        // replaced
+                        return newValue;
+                    }
+
+                    // some other value replaced old value. try again.
+                }
+            }
+        }
+    }
+
+
+    /**
+     * {@inheritDoc}
+     *
+     * @implSpec
+     * The default implementation is equivalent to performing the following
+     * steps for this {@code map}, then returning the current value or
+     * {@code null} if absent:
+     *
+     * <pre> {@code
+     * V oldValue = map.get(key);
+     * V newValue = (oldValue == null) ? value :
+     *              remappingFunction.apply(oldValue, value);
+     * if (newValue == null)
+     *     map.remove(key);
+     * else
+     *     map.put(key, newValue);
+     * }</pre>
+     *
+     * <p>The default implementation may retry these steps when multiple
+     * threads attempt updates including potentially calling the remapping
+     * function multiple times.
+     *
+     * <p>This implementation assumes that the ConcurrentMap cannot contain null
+     * values and {@code get()} returning null unambiguously means the key is
+     * absent. Implementations which support null values <strong>must</strong>
+     * override this default implementation.
+     *
+     * @throws UnsupportedOperationException {@inheritDoc}
+     * @throws ClassCastException {@inheritDoc}
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.8
+     */
+    @Override
+    default V merge(K key, V value,
+            BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
+        Objects.requireNonNull(remappingFunction);
+        Objects.requireNonNull(value);
+        V oldValue = get(key);
+        for (;;) {
+            if (oldValue != null) {
+                V newValue = remappingFunction.apply(oldValue, value);
+                if (newValue != null) {
+                    if (replace(key, oldValue, newValue))
+                        return newValue;
+                } else if (remove(key, oldValue)) {
+                    return null;
+                }
+                oldValue = get(key);
+            } else {
+                if ((oldValue = putIfAbsent(key, value)) == null) {
+                    return value;
+                }
+            }
+        }
+    }
+}