Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 275 insertions, 0 deletions

diff --git a/guava/src/com/google/common/cache/AbstractCache.java b/guava/src/com/google/common/cache/AbstractCache.java
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+/*
+ * Copyright (C) 2011 The Guava Authors
+ *
+ * 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 com.google.common.cache;
+
+import com.google.common.annotations.Beta;
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+
+import java.util.Map;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ExecutionException;
+
+/**
+ * This class provides a skeletal implementation of the {@code Cache} interface to minimize the
+ * effort required to implement this interface.
+ *
+ * <p>To implement a cache, the programmer needs only to extend this class and provide an
+ * implementation for the {@link #put} and {@link #getIfPresent} methods. {@link #getAllPresent} is
+ * implemented in terms of {@link #getIfPresent}; {@link #putAll} is implemented in terms of
+ * {@link #put}, {@link #invalidateAll(Iterable)} is implemented in terms of {@link #invalidate}.
+ * The method {@link #cleanUp} is a no-op. All other methods throw an
+ * {@link UnsupportedOperationException}.
+ *
+ * @author Charles Fry
+ * @since 10.0
+ */
+@Beta
+@GwtCompatible
+public abstract class AbstractCache<K, V> implements Cache<K, V> {
+
+  /** Constructor for use by subclasses. */
+  protected AbstractCache() {}
+
+  /**
+   * @since 11.0
+   */
+  @Override
+  public V get(K key, Callable<? extends V> valueLoader) throws ExecutionException {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * This implementation of {@code getAllPresent} lacks any insight into the internal cache data
+   * structure, and is thus forced to return the query keys instead of the cached keys. This is only
+   * possible with an unsafe cast which requires {@code keys} to actually be of type {@code K}.
+   *
+   * {@inheritDoc}
+   *
+   * @since 11.0
+   */
+  @Override
+  public ImmutableMap<K, V> getAllPresent(Iterable<?> keys) {
+    Map<K, V> result = Maps.newLinkedHashMap();
+    for (Object key : keys) {
+      if (!result.containsKey(key)) {
+        @SuppressWarnings("unchecked")
+        K castKey = (K) key;
+        result.put(castKey, getIfPresent(key));
+      }
+    }
+    return ImmutableMap.copyOf(result);
+  }
+
+  /**
+   * @since 11.0
+   */
+  @Override
+  public void put(K key, V value) {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @since 12.0
+   */
+  @Override
+  public void putAll(Map<? extends K, ? extends V> m) {
+    for (Map.Entry<? extends K, ? extends V> entry : m.entrySet()) {
+      put(entry.getKey(), entry.getValue());
+    }
+  }
+
+  @Override
+  public void cleanUp() {}
+
+  @Override
+  public long size() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void invalidate(Object key) {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @since 11.0
+   */
+  @Override
+  public void invalidateAll(Iterable<?> keys) {
+    for (Object key : keys) {
+      invalidate(key);
+    }
+  }
+
+  @Override
+  public void invalidateAll() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public CacheStats stats() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public ConcurrentMap<K, V> asMap() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Accumulates statistics during the operation of a {@link Cache} for presentation by {@link
+   * Cache#stats}. This is solely intended for consumption by {@code Cache} implementors.
+   *
+   * @since 10.0
+   */
+  @Beta
+  public interface StatsCounter {
+    /**
+     * Records cache hits. This should be called when a cache request returns a cached value.
+     *
+     * @param count the number of hits to record
+     * @since 11.0
+     */
+    public void recordHits(int count);
+
+    /**
+     * Records cache misses. This should be called when a cache request returns a value that was
+     * not found in the cache. This method should be called by the loading thread, as well as by
+     * threads blocking on the load. Multiple concurrent calls to {@link Cache} lookup methods with
+     * the same key on an absent value should result in a single call to either
+     * {@code recordLoadSuccess} or {@code recordLoadException} and multiple calls to this method,
+     * despite all being served by the results of a single load operation.
+     *
+     * @param count the number of misses to record
+     * @since 11.0
+     */
+    public void recordMisses(int count);
+
+    /**
+     * Records the successful load of a new entry. This should be called when a cache request
+     * causes an entry to be loaded, and the loading completes successfully. In contrast to
+     * {@link #recordMisses}, this method should only be called by the loading thread.
+     *
+     * @param loadTime the number of nanoseconds the cache spent computing or retrieving the new
+     *     value
+     */
+    public void recordLoadSuccess(long loadTime);
+
+    /**
+     * Records the failed load of a new entry. This should be called when a cache request causes
+     * an entry to be loaded, but an exception is thrown while loading the entry. In contrast to
+     * {@link #recordMisses}, this method should only be called by the loading thread.
+     *
+     * @param loadTime the number of nanoseconds the cache spent computing or retrieving the new
+     *     value prior to an exception being thrown
+     */
+    public void recordLoadException(long loadTime);
+
+    /**
+     * Records the eviction of an entry from the cache. This should only been called when an entry
+     * is evicted due to the cache's eviction strategy, and not as a result of manual {@linkplain
+     * Cache#invalidate invalidations}.
+     */
+    public void recordEviction();
+
+    /**
+     * Returns a snapshot of this counter's values. Note that this may be an inconsistent view, as
+     * it may be interleaved with update operations.
+     */
+    public CacheStats snapshot();
+  }
+
+  /**
+   * A thread-safe {@link StatsCounter} implementation for use by {@link Cache} implementors.
+   *
+   * @since 10.0
+   */
+  @Beta
+  public static final class SimpleStatsCounter implements StatsCounter {
+    private final LongAdder hitCount = new LongAdder();
+    private final LongAdder missCount = new LongAdder();
+    private final LongAdder loadSuccessCount = new LongAdder();
+    private final LongAdder loadExceptionCount = new LongAdder();
+    private final LongAdder totalLoadTime = new LongAdder();
+    private final LongAdder evictionCount = new LongAdder();
+
+    /**
+     * Constructs an instance with all counts initialized to zero.
+     */
+    public SimpleStatsCounter() {}
+
+    /**
+     * @since 11.0
+     */
+    @Override
+    public void recordHits(int count) {
+      hitCount.add(count);
+    }
+
+    /**
+     * @since 11.0
+     */
+    @Override
+    public void recordMisses(int count) {
+      missCount.add(count);
+    }
+
+    @Override
+    public void recordLoadSuccess(long loadTime) {
+      loadSuccessCount.increment();
+      totalLoadTime.add(loadTime);
+    }
+
+    @Override
+    public void recordLoadException(long loadTime) {
+      loadExceptionCount.increment();
+      totalLoadTime.add(loadTime);
+    }
+
+    @Override
+    public void recordEviction() {
+      evictionCount.increment();
+    }
+
+    @Override
+    public CacheStats snapshot() {
+      return new CacheStats(
+          hitCount.sum(),
+          missCount.sum(),
+          loadSuccessCount.sum(),
+          loadExceptionCount.sum(),
+          totalLoadTime.sum(),
+          evictionCount.sum());
+    }
+
+    /**
+     * Increments all counters by the values in {@code other}.
+     */
+    public void incrementBy(StatsCounter other) {
+      CacheStats otherStats = other.snapshot();
+      hitCount.add(otherStats.hitCount());
+      missCount.add(otherStats.missCount());
+      loadSuccessCount.add(otherStats.loadSuccessCount());
+      loadExceptionCount.add(otherStats.loadExceptionCount());
+      totalLoadTime.add(otherStats.totalLoadTime());
+      evictionCount.add(otherStats.evictionCount());
+    }
+  }
+}