AI 143890: Fixes #1749387. Improve the pooling of the VelocityTracker class. This introduces a new, hidden, API for pooling objects easily.

  BUG=1749387

Automated import of CL 143890

6 files changed, 252 insertions, 0 deletions

diff --git a/core/java/android/util/FinitePool.java b/core/java/android/util/FinitePool.java
new file mode 100644
index 0000000..3ef8293
--- /dev/null
+++ b/core/java/android/util/FinitePool.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ * @hide
+ */
+class FinitePool<T extends Poolable<T>> implements Pool<T> {
+    /**
+     * Factory used to create new pool objects
+     */
+    private final PoolableManager<T> mManager;
+    /**
+     * Maximum number of objects in the pool
+     */
+    private final int mLimit;
+    /**
+     * If true, mLimit is ignored
+     */
+    private final boolean mInfinite;
+
+    /**
+     * Next object to acquire
+     */
+    private T mRoot;
+    /**
+     * Number of objects in the pool
+     */
+    private int mPoolCount;
+
+    FinitePool(PoolableManager<T> manager) {
+        mManager = manager;
+        mLimit = 0;
+        mInfinite = true;
+    }
+
+    FinitePool(PoolableManager<T> manager, int limit) {
+        if (limit <= 0) throw new IllegalArgumentException("The pool limit must be > 0");
+
+        mManager = manager;
+        mLimit = limit;
+        mInfinite = false;
+    }
+
+    public T acquire() {
+        T element;
+
+        if (mRoot != null) {
+            element = mRoot;
+            mRoot = element.getNextPoolable();
+            mPoolCount--;
+        } else {
+            element = mManager.newInstance();
+        }
+
+        if (element != null) {
+            element.setNextPoolable(null);
+            mManager.onAcquired(element);            
+        }
+
+        return element;
+    }
+
+    public void release(T element) {
+        if (mInfinite || mPoolCount < mLimit) {
+            mPoolCount++;
+            element.setNextPoolable(mRoot);
+            mRoot = element;
+        }
+        mManager.onReleased(element);
+    }
+}
diff --git a/core/java/android/util/Pool.java b/core/java/android/util/Pool.java
new file mode 100644
index 0000000..8cd4f3e
--- /dev/null
+++ b/core/java/android/util/Pool.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ * @hide
+ */
+public interface Pool<T extends Poolable<T>> {
+    public abstract T acquire();
+    public abstract void release(T element);
+}
diff --git a/core/java/android/util/PoolFactory.java b/core/java/android/util/PoolFactory.java
new file mode 100644
index 0000000..4f72bf7
--- /dev/null
+++ b/core/java/android/util/PoolFactory.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ * @hide
+ */
+public class PoolFactory {
+    private PoolFactory() {
+    }
+
+    public static <T extends Poolable<T>> Pool<T> simplePool(PoolableManager<T> manager) {
+        return new FinitePool<T>(manager);
+    }
+    
+    public static <T extends Poolable<T>> Pool<T> finitePool(PoolableManager<T> manager, int limit) {
+        return new FinitePool<T>(manager, limit);
+    }
+
+    public static <T extends Poolable<T>> Pool<T> synchronizedPool(Pool<T> pool) {
+        return new SynchronizedPool<T>(pool);
+    }
+
+    public static <T extends Poolable<T>> Pool<T> synchronizedPool(Pool<T> pool, Object lock) {
+        return new SynchronizedPool<T>(pool, lock);
+    }
+}
diff --git a/core/java/android/util/Poolable.java b/core/java/android/util/Poolable.java
new file mode 100644
index 0000000..fd9bd9b
--- /dev/null
+++ b/core/java/android/util/Poolable.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ * @hide
+ */
+public interface Poolable<T> {
+    void setNextPoolable(T element);
+    T getNextPoolable();
+}
diff --git a/core/java/android/util/PoolableManager.java b/core/java/android/util/PoolableManager.java
new file mode 100644
index 0000000..8773e63
--- /dev/null
+++ b/core/java/android/util/PoolableManager.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ * @hide
+ */
+public interface PoolableManager<T extends Poolable<T>> {
+    T newInstance();
+
+    void onAcquired(T element);
+    void onReleased(T element);
+}
diff --git a/core/java/android/util/SynchronizedPool.java b/core/java/android/util/SynchronizedPool.java
new file mode 100644
index 0000000..651e0c3
--- /dev/null
+++ b/core/java/android/util/SynchronizedPool.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+/**
+ *
+ * @hide
+ */
+class SynchronizedPool<T extends Poolable<T>> implements Pool<T> {
+    private final Pool<T> mPool;
+    private final Object mLock;
+
+    public SynchronizedPool(Pool<T> pool) {
+        mPool = pool;
+        mLock = this;
+    }
+
+    public SynchronizedPool(Pool<T> pool, Object lock) {
+        mPool = pool;
+        mLock = lock;
+    }
+
+    public T acquire() {
+        synchronized (mLock) {
+            return mPool.acquire();
+        }
+    }
+
+    public void release(T element) {
+        synchronized (mLock) {
+            mPool.release(element);
+        }
+    }
+}