Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 163 insertions, 0 deletions

diff --git a/guava/src/com/google/common/cache/LoadingCache.java b/guava/src/com/google/common/cache/LoadingCache.java
new file mode 100644
index 0000000..05b1312
--- /dev/null
+++ b/guava/src/com/google/common/cache/LoadingCache.java
@@ -0,0 +1,163 @@
+/*
+ * 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.base.Function;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.util.concurrent.ExecutionError;
+import com.google.common.util.concurrent.UncheckedExecutionException;
+
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ExecutionException;
+
+/**
+ * A semi-persistent mapping from keys to values. Values are automatically loaded by the cache,
+ * and are stored in the cache until either evicted or manually invalidated.
+ *
+ * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
+ * by multiple concurrent threads.
+ *
+ * <p>When evaluated as a {@link Function}, a cache yields the same result as invoking
+ * {@link #getUnchecked}.
+ *
+ * <p>Note that while this class is still annotated as {@link Beta}, the API is frozen from a
+ * consumer's standpoint. In other words existing methods are all considered {@code non-Beta} and
+ * won't be changed without going through an 18 month deprecation cycle; however new methods may be
+ * added at any time.
+ *
+ * @author Charles Fry
+ * @since 11.0
+ */
+@Beta
+@GwtCompatible
+public interface LoadingCache<K, V> extends Cache<K, V>, Function<K, V> {
+
+  /**
+   * Returns the value associated with {@code key} in this cache, first loading that value if
+   * necessary. No observable state associated with this cache is modified until loading completes.
+   *
+   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
+   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that
+   * multiple threads can concurrently load values for distinct keys.
+   *
+   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
+   * into the cache. Newly loaded values are added to the cache using
+   * {@code Cache.asMap().putIfAbsent} after loading has completed; if another value was associated
+   * with {@code key} while the new value was loading then a removal notification will be sent for
+   * the new value.
+   *
+   * <p>If the cache loader associated with this cache is known not to throw checked
+   * exceptions, then prefer {@link #getUnchecked} over this method.
+   *
+   * @throws ExecutionException if a checked exception was thrown while loading the value
+   * @throws UncheckedExecutionException if an unchecked exception was thrown while loading the
+   *     value
+   * @throws ExecutionError if an error was thrown while loading the value
+   */
+  V get(K key) throws ExecutionException;
+
+  /**
+   * Returns the value associated with {@code key} in this cache, first loading that value if
+   * necessary. No observable state associated with this cache is modified until loading
+   * completes. Unlike {@link #get}, this method does not throw a checked exception, and thus should
+   * only be used in situations where checked exceptions are not thrown by the cache loader.
+   *
+   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
+   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that
+   * multiple threads can concurrently load values for distinct keys.
+   *
+   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
+   * into the cache. Newly loaded values are added to the cache using
+   * {@code Cache.asMap().putIfAbsent} after loading has completed; if another value was associated
+   * with {@code key} while the new value was loading then a removal notification will be sent for
+   * the new value.
+   *
+   * <p><b>Warning:</b> this method silently converts checked exceptions to unchecked exceptions,
+   * and should not be used with cache loaders which throw checked exceptions. In such cases use
+   * {@link #get} instead.
+   *
+   * @throws UncheckedExecutionException if an exception was thrown while loading the value,
+   *     regardless of whether the exception was checked or unchecked
+   * @throws ExecutionError if an error was thrown while loading the value
+   */
+  V getUnchecked(K key);
+
+  /**
+   * Returns a map of the values associated with {@code keys}, creating or retrieving those values
+   * if necessary. The returned map contains entries that were already cached, combined with newly
+   * loaded entries; it will never contain null keys or values.
+   *
+   * <p>Caches loaded by a {@link CacheLoader} will issue a single request to
+   * {@link CacheLoader#loadAll} for all keys which are not already present in the cache. All
+   * entries returned by {@link CacheLoader#loadAll} will be stored in the cache, over-writing
+   * any previously cached values. This method will throw an exception if
+   * {@link CacheLoader#loadAll} returns {@code null}, returns a map containing null keys or values,
+   * or fails to return an entry for each requested key.
+   *
+   * <p>Note that duplicate elements in {@code keys}, as determined by {@link Object#equals}, will
+   * be ignored.
+   *
+   * @throws ExecutionException if a checked exception was thrown while loading the values
+   * @throws UncheckedExecutionException if an unchecked exception was thrown while loading the
+   *     values
+   * @throws ExecutionError if an error was thrown while loading the values
+   * @since 11.0
+   */
+  ImmutableMap<K, V> getAll(Iterable<? extends K> keys) throws ExecutionException;
+
+  /**
+   * Discouraged. Provided to satisfy the {@code Function} interface; use {@link #get} or
+   * {@link #getUnchecked} instead.
+   *
+   * @throws UncheckedExecutionException if an exception was thrown while loading the value,
+   *     regardless of whether the exception was checked or unchecked
+   * @throws ExecutionError if an error was thrown while loading the value
+   */
+  @Override
+  V apply(K key);
+
+  /**
+   * Loads a new value for key {@code key}, possibly asynchronously. While the new value is loading
+   * the previous value (if any) will continue to be returned by {@code get(key)} unless it is
+   * evicted. If the new value is loaded successfully it will replace the previous value in the
+   * cache; if an exception is thrown while refreshing the previous value will remain, <i>and the
+   * exception will be logged (using {@link java.util.logging.Logger}) and swallowed</i>.
+   *
+   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#reload} if the
+   * cache currently contains a value for {@code key}, and {@link CacheLoader#load} otherwise.
+   * Loading is asynchronous only if {@link CacheLoader#reload} was overridden with an
+   * asynchronous implementation.
+   *
+   * <p>Returns without doing anything if another thread is currently loading the value for
+   * {@code key}. If the cache loader associated with this cache performs refresh asynchronously
+   * then this method may return before refresh completes.
+   *
+   * @since 11.0
+   */
+  void refresh(K key);
+
+  /**
+   * {@inheritDoc}
+   *
+   * <p><b>Note that although the view <i>is</i> modifiable, no method on the returned map will ever
+   * cause entries to be automatically loaded.</b>
+   */
+  @Override
+  ConcurrentMap<K, V> asMap();
+}