Callback on any removal, not just evictions. (7db1b40a) · Commits · e / os / android_frameworks_base

api/current.xml

+24 −5

Original line number	Diff line number	Diff line
		@@ -206578,7 +206578,7 @@
		synchronized="false"
		static="false"
		final="false"
		deprecated="not deprecated"
		deprecated="deprecated"
		visibility="protected"
		>
		<parameter name="key" type="K">
		@@ -206586,11 +206586,30 @@
		<parameter name="value" type="V">
		</parameter>
		</method>
		<method name="entryRemoved"
		return="void"
		abstract="false"
		native="false"
		synchronized="false"
		static="false"
		final="false"
		deprecated="not deprecated"
		visibility="protected"
		>
		<parameter name="evicted" type="boolean">
		</parameter>
		<parameter name="key" type="K">
		</parameter>
		<parameter name="oldValue" type="V">
		</parameter>
		<parameter name="newValue" type="V">
		</parameter>
		</method>
		<method name="evictAll"
		return="void"
		abstract="false"
		native="false"
		synchronized="true"
		synchronized="false"
		static="false"
		final="true"
		deprecated="not deprecated"
		@@ -206612,7 +206631,7 @@
		return="V"
		abstract="false"
		native="false"
		synchronized="true"
		synchronized="false"
		static="false"
		final="true"
		deprecated="not deprecated"
		@@ -206658,7 +206677,7 @@
		return="V"
		abstract="false"
		native="false"
		synchronized="true"
		synchronized="false"
		static="false"
		final="true"
		deprecated="not deprecated"
		@@ -206684,7 +206703,7 @@
		return="V"
		abstract="false"
		native="false"
		synchronized="true"
		synchronized="false"
		static="false"
		final="true"
		deprecated="not deprecated"

core/java/android/util/LruCache.java

+122 −42

Original line number	Diff line number	Diff line
		@@ -26,8 +26,7 @@ import java.util.Map;
		* become eligible for garbage collection.
		*
		* <p>If your cached values hold resources that need to be explicitly released,
		* override {@link #entryEvicted}. This method is only invoked when values are
		* evicted. Values replaced by calls to {@link #put} must be released manually.
		* override {@link #entryRemoved}.
		*
		* <p>If a cache miss should be computed on demand for the corresponding keys,
		* override {@link #create}. This simplifies the calling code, allowing it to
		@@ -88,29 +87,52 @@ public class LruCache<K, V> {
		* head of the queue. This returns null if a value is not cached and cannot
		* be created.
		*/
		public synchronized final V get(K key) {
		public final V get(K key) {
		if (key == null) {
		throw new NullPointerException("key == null");
		}

		V result = map.get(key);
		if (result != null) {
		V mapValue;
		synchronized (this) {
		mapValue = map.get(key);
		if (mapValue != null) {
		hitCount++;
		return result;
		return mapValue;
		}

		missCount++;
		}

		/*
		* Attempt to create a value. This may take a long time, and the map
		* may be different when create() returns. If a conflicting value was
		* added to the map while create() was working, we leave that value in
		* the map and release the created value.
		*/

		// TODO: release the lock while calling this potentially slow user code
		result = create(key);
		V createdValue = create(key);
		if (createdValue == null) {
		return null;
		}

		if (result != null) {
		synchronized (this) {
		createCount++;
		size += safeSizeOf(key, result);
		map.put(key, result);
		mapValue = map.put(key, createdValue);

		if (mapValue != null) {
		// There was a conflict so undo that last put
		map.put(key, mapValue);
		} else {
		size += safeSizeOf(key, createdValue);
		}
		}

		if (mapValue != null) {
		entryRemoved(false, key, createdValue, mapValue);
		return mapValue;
		} else {
		trimToSize(maxSize);
		return createdValue;
		}
		return result;
		}

		/**
		@@ -120,41 +142,60 @@ public class LruCache<K, V> {
		* @return the previous value mapped by {@code key}. Although that entry is
		* no longer cached, it has not been passed to {@link #entryEvicted}.
		*/
		public synchronized final V put(K key, V value) {
		public final V put(K key, V value) {
		if (key == null \|\| value == null) {
		throw new NullPointerException("key == null \|\| value == null");
		}

		V previous;
		synchronized (this) {
		putCount++;
		size += safeSizeOf(key, value);
		V previous = map.put(key, value);
		previous = map.put(key, value);
		if (previous != null) {
		size -= safeSizeOf(key, previous);
		}
		}

		if (previous != null) {
		entryRemoved(false, key, previous, value);
		}

		trimToSize(maxSize);
		return previous;
		}

		/**
		* @param maxSize the maximum size of the cache before returning. May be -1
		* to evict even 0-sized elements.
		*/
		private void trimToSize(int maxSize) {
		while (size > maxSize) {
		Map.Entry<K, V> toEvict = map.eldest(); // equal to map.entrySet().iterator().next();
		while (true) {
		K key;
		V value;
		synchronized (this) {
		if (size < 0 \|\| (map.isEmpty() && size != 0)) {
		throw new IllegalStateException(getClass().getName()
		+ ".sizeOf() is reporting inconsistent results!");
		}

		if (size <= maxSize) {
		break;
		}

		Map.Entry<K, V> toEvict = map.eldest();
		if (toEvict == null) {
		break; // map is empty; if size is not 0 then throw an error below
		break;
		}

		K key = toEvict.getKey();
		V value = toEvict.getValue();
		key = toEvict.getKey();
		value = toEvict.getValue();
		map.remove(key);
		size -= safeSizeOf(key, value);
		evictionCount++;

		// TODO: release the lock while calling this potentially slow user code
		entryEvicted(key, value);
		}

		if (size < 0 \|\| (map.isEmpty() && size != 0)) {
		throw new IllegalStateException(getClass().getName()
		+ ".sizeOf() is reporting inconsistent results!");
		entryEvicted(key, value);
		}
		}

		@@ -164,28 +205,67 @@ public class LruCache<K, V> {
		* @return the previous value mapped by {@code key}. Although that entry is
		* no longer cached, it has not been passed to {@link #entryEvicted}.
		*/
		public synchronized final V remove(K key) {
		public final V remove(K key) {
		if (key == null) {
		throw new NullPointerException("key == null");
		}

		V previous = map.remove(key);
		V previous;
		synchronized (this) {
		previous = map.remove(key);
		if (previous != null) {
		size -= safeSizeOf(key, previous);
		}
		}

		if (previous != null) {
		entryRemoved(false, key, previous, null);
		}

		return previous;
		}

		/**
		* Called for entries that have reached the tail of the least recently used
		* queue and are be removed. The default implementation does nothing.
		* Calls {@link #entryRemoved}.
		*
		* @deprecated replaced by entryRemoved
		*/
		protected void entryEvicted(K key, V value) {}
		@Deprecated
		protected void entryEvicted(K key, V value) {
		entryRemoved(true, key, value, null);
		}

		/**
		* Called for entries that have been evicted or removed. This method is
		* invoked when a value is evicted to make space, removed by a call to
		* {@link #remove}, or replaced by a call to {@link #put}. The default
		* implementation does nothing.
		*
		* <p>The method is called without synchronization: other threads may
		* access the cache while this method is executing.
		*
		* @param evicted true if the entry is being removed to make space, false
		* if the removal was caused by a {@link #put} or {@link #remove}.
		* @param newValue the new value for {@code key}, if it exists. If non-null,
		* this removal was caused by a {@link #put}. Otherwise it was caused by
		* an eviction or a {@link #remove}.
		*/
		protected void entryRemoved(boolean evicted, K key, V oldValue, V newValue) {}

		/**
		* Called after a cache miss to compute a value for the corresponding key.
		* Returns the computed value or null if no value can be computed. The
		* default implementation returns null.
		*
		* <p>The method is called without synchronization: other threads may
		* access the cache while this method is executing.
		*
		* <p>If a value for {@code key} exists in the cache when this method
		* returns, the created value will be released with {@link #entryRemoved}
		* and discarded. This can occur when multiple threads request the same key
		* at the same time (causing multiple values to be created), or when one
		* thread calls {@link #put} while another is creating a value for the same
		* key.
		*/
		protected V create(K key) {
		return null;
		@@ -213,7 +293,7 @@ public class LruCache<K, V> {
		/**
		* Clear the cache, calling {@link #entryEvicted} on each removed entry.
		*/
		public synchronized final void evictAll() {
		public final void evictAll() {
		trimToSize(-1); // -1 will evict 0-sized elements
		}

core/tests/coretests/src/android/util/LruCacheTest.java

+113 −28

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@ package android.util;

		import java.util.ArrayList;
		import java.util.Arrays;
		import java.util.Collections;
		import java.util.List;
		import java.util.Map;
		import junit.framework.TestCase;
		@@ -166,22 +167,16 @@ public final class LruCacheTest extends TestCase {
		}

		public void testEntryEvictedWhenFull() {
		List<String> expectedEvictionLog = new ArrayList<String>();
		final List<String> evictionLog = new ArrayList<String>();
		LruCache<String, String> cache = new LruCache<String, String>(3) {
		@Override protected void entryEvicted(String key, String value) {
		evictionLog.add(key + "=" + value);
		}
		};
		List<String> log = new ArrayList<String>();
		LruCache<String, String> cache = newRemovalLogCache(log);

		cache.put("a", "A");
		cache.put("b", "B");
		cache.put("c", "C");
		assertEquals(expectedEvictionLog, evictionLog);
		assertEquals(Collections.<String>emptyList(), log);

		cache.put("d", "D");
		expectedEvictionLog.add("a=A");
		assertEquals(expectedEvictionLog, evictionLog);
		assertEquals(Arrays.asList("a=A"), log);
		}

		/**
		@@ -309,19 +304,14 @@ public final class LruCacheTest extends TestCase {
		}

		public void testEvictAll() {
		final List<String> evictionLog = new ArrayList<String>();
		LruCache<String, String> cache = new LruCache<String, String>(10) {
		@Override protected void entryEvicted(String key, String value) {
		evictionLog.add(key + "=" + value);
		}
		};

		List<String> log = new ArrayList<String>();
		LruCache<String, String> cache = newRemovalLogCache(log);
		cache.put("a", "A");
		cache.put("b", "B");
		cache.put("c", "C");
		cache.evictAll();
		assertEquals(0, cache.size());
		assertEquals(Arrays.asList("a=A", "b=B", "c=C"), evictionLog);
		assertEquals(Arrays.asList("a=A", "b=B", "c=C"), log);
		}

		public void testEvictAllEvictsSizeZeroElements() {
		@@ -337,16 +327,6 @@ public final class LruCacheTest extends TestCase {
		assertSnapshot(cache);
		}

		public void testRemoveDoesNotCallEntryEvicted() {
		LruCache<String, String> cache = new LruCache<String, String>(10) {
		@Override protected void entryEvicted(String key, String value) {
		fail();
		}
		};
		cache.put("a", "A");
		assertEquals("A", cache.remove("a"));
		}

		public void testRemoveWithCustomSizes() {
		LruCache<String, String> cache = new LruCache<String, String>(10) {
		@Override protected int sizeOf(String key, String value) {
		@@ -376,6 +356,99 @@ public final class LruCacheTest extends TestCase {
		}
		}

		public void testRemoveCallsEntryRemoved() {
		List<String> log = new ArrayList<String>();
		LruCache<String, String> cache = newRemovalLogCache(log);
		cache.put("a", "A");
		cache.remove("a");
		assertEquals(Arrays.asList("a=A>null"), log);
		}

		public void testPutCallsEntryRemoved() {
		List<String> log = new ArrayList<String>();
		LruCache<String, String> cache = newRemovalLogCache(log);
		cache.put("a", "A");
		cache.put("a", "A2");
		assertEquals(Arrays.asList("a=A>A2"), log);
		}

		public void testEntryRemovedIsCalledWithoutSynchronization() {
		LruCache<String, String> cache = new LruCache<String, String>(3) {
		@Override protected void entryRemoved(
		boolean evicted, String key, String oldValue, String newValue) {
		assertFalse(Thread.holdsLock(this));
		}
		};

		cache.put("a", "A");
		cache.put("a", "A2"); // replaced
		cache.put("b", "B");
		cache.put("c", "C");
		cache.put("d", "D"); // single eviction
		cache.remove("a"); // removed
		cache.evictAll(); // multiple eviction
		}

		public void testCreateIsCalledWithoutSynchronization() {
		LruCache<String, String> cache = new LruCache<String, String>(3) {
		@Override protected String create(String key) {
		assertFalse(Thread.holdsLock(this));
		return null;
		}
		};

		cache.get("a");
		}

		/**
		* Test what happens when a value is added to the map while create is
		* working. The map value should be returned by get(), and the created value
		* should be released with entryRemoved().
		*/
		public void testCreateWithConcurrentPut() {
		final List<String> log = new ArrayList<String>();
		LruCache<String, String> cache = new LruCache<String, String>(3) {
		@Override protected String create(String key) {
		put(key, "B");
		return "A";
		}
		@Override protected void entryRemoved(
		boolean evicted, String key, String oldValue, String newValue) {
		log.add(key + "=" + oldValue + ">" + newValue);
		}
		};

		assertEquals("B", cache.get("a"));
		assertEquals(Arrays.asList("a=A>B"), log);
		}

		/**
		* Test what happens when two creates happen concurrently. The result from
		* the first create to return is returned by both gets. The other created
		* values should be released with entryRemove().
		*/
		public void testCreateWithConcurrentCreate() {
		final List<String> log = new ArrayList<String>();
		LruCache<String, Integer> cache = new LruCache<String, Integer>(3) {
		int callCount = 0;
		@Override protected Integer create(String key) {
		if (callCount++ == 0) {
		assertEquals(2, get(key).intValue());
		return 1;
		} else {
		return 2;
		}
		}
		@Override protected void entryRemoved(
		boolean evicted, String key, Integer oldValue, Integer newValue) {
		log.add(key + "=" + oldValue + ">" + newValue);
		}
		};

		assertEquals(2, cache.get("a").intValue());
		assertEquals(Arrays.asList("a=1>2"), log);
		}

		private LruCache<String, String> newCreatingCache() {
		return new LruCache<String, String>(3) {
		@Override protected String create(String key) {
		@@ -384,6 +457,18 @@ public final class LruCacheTest extends TestCase {
		};
		}

		private LruCache<String, String> newRemovalLogCache(final List<String> log) {
		return new LruCache<String, String>(3) {
		@Override protected void entryRemoved(
		boolean evicted, String key, String oldValue, String newValue) {
		String message = evicted
		? (key + "=" + oldValue)
		: (key + "=" + oldValue + ">" + newValue);
		log.add(message);
		}
		};
		}

		private void assertHit(LruCache<String, String> cache, String key, String value) {
		assertEquals(value, cache.get(key));
		expectedHitCount++;