Add a configurable version of the policy engine based on PFW

This patch adds a configurable version of the policy engine
based on the parameter framework.
This configurable engine shall be activated with a flag
USE_CONFIGURABLE_AUDIO_POLICY within BoardConfig.mk

This patch provides the generic configuration as an example.
This configuration provides the same user experience as the default
policy engine.

- Fix M Issue on configurable policy engine version.

- Remove the "empty static lib include trick" hack

The code was using a hack to import headers only through an empty lib.
This trick was used not only by the PFW and its plugin but also internally
with policy.

This patch removes this hack and either links againts the real libraries if exist
or point on the path of the header.
However, since header directories are not recursively detected on Andoid, we need to manually
add all necessary libraries. (for example libicuuc needed by libxml2)

- let the build system decide which compiler and which stl is to be used

- Disable by default Audio Policy Settings XML file generation at compilation time

In order not to depend on python tool for the configurable policy example,
this patch adds the generated Settings XML file and disables the generation
from .pfw files at compile time.
If the user wishes to regenerate it, he may use the pfw_rebuild_settings
option.

- Fix Clang issues within Configurable Audio Policy

Fix compilation issues revealed when switching to CLANG compiler
within the configurable version of policy engine.

Change-Id: I3edc26db94c0bf8a76430ab8081bae52e9193705
Signed-off-by: François Gaffie <francois.gaffie@intel.com>

13 files changed, 1560 insertions, 0 deletions

diff --git a/services/audiopolicy/engineconfigurable/src/Collection.h b/services/audiopolicy/engineconfigurable/src/Collection.h
new file mode 100755
index 0000000..8f17b15
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Collection.h
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include "Element.h"
+#include "Stream.h"
+#include "Strategy.h"
+#include "Usage.h"
+#include "InputSource.h"
+#include <utils/Errors.h>
+#include <system/audio.h>
+#include <utils/Log.h>
+#include <map>
+#include <stdint.h>
+#include <string>
+
+namespace android
+{
+namespace audio_policy
+{
+
+/**
+ * Collection of policy element as a map indexed with a their UID type.
+ *
+ * @tparam Key type of the policy element indexing the collection.
+ *         Policy Element supported are:
+ *                      - Strategy
+ *                      - Stream
+ *                      - InputSource
+ *                      - Usage.
+ */
+template <typename Key>
+class Collection : public std::map<Key, Element<Key> *>
+{
+private:
+    typedef Element<Key> T;
+    typedef typename std::map<Key, T *>::iterator CollectionIterator;
+    typedef typename std::map<Key, T *>::const_iterator CollectionConstIterator;
+
+public:
+    Collection()
+    {
+        collectionSupported();
+    }
+
+    /**
+     * Add a policy element to the collection. Policy elements are streams, strategies, input
+     * sources, ... Compile time error generated if called with not supported collection.
+     * It also set the key as the unique identifier of the policy element.
+     *
+     * @tparam Key indexing the collection of policy element.
+     * @param[in] name of the policy element to find.
+     * @param[in] key to be used to index this new policy element.
+     *
+     * @return NO_ERROR if the policy element has been successfully added to the collection.
+     */
+    status_t add(const std::string &name, Key key)
+    {
+        if ((*this).find(key) != (*this).end()) {
+            ALOGW("%s: element %s already added", __FUNCTION__, name.c_str());
+            return BAD_VALUE;
+        }
+        (*this)[key] = new T(name);
+        ALOGD("%s: adding element %s to collection", __FUNCTION__, name.c_str());
+        return (*this)[key]->setIdentifier(key);
+    }
+
+    /**
+     * Get a policy element from the collection by its key. Policy elements are streams, strategies,
+     * input sources, ... Compile time error generated if called with not supported collection.
+     *
+     * @tparam Key indexing the collection of policy element.
+     * @param[in] key of the policy element to find.
+     *
+     * @return valid pointer on policy element if found, NULL otherwise.
+     */
+    T *get(Key key) const
+    {
+        CollectionConstIterator it = (*this).find(key);
+        return (it == (*this).end()) ? NULL : it->second;
+    }
+
+    /**
+     * Find a policy element from the collection by its name. Policy elements are streams,
+     * strategies, input sources, ...
+     * Compile time error generated if called with not supported collection.
+     *
+     * @tparam Key indexing the collection of policy element.
+     * @param[in] name of the policy element to find.
+     * @param[in] elementsMap maps of policy elements to search into.
+     *
+     * @return valid pointer on element if found, NULL otherwise.
+     */
+    T *findByName(const std::string &name) const
+    {
+
+        CollectionConstIterator it;
+        for (it = (*this).begin(); it != (*this).end(); ++it) {
+            T *element = it->second;
+            if (element->getName() == name) {
+                return element;
+            }
+        }
+        return NULL;
+    }
+
+    /**
+     * Removes all the elements from the list and destroy them.
+     */
+    void clear()
+    {
+        CollectionIterator it;
+        for (it = (*this).begin(); it != (*this).end(); ++it) {
+            delete it->second;
+        }
+        (*this).clear();
+    }
+
+private:
+    /**
+     * provide a compile time error if no specialization is provided for a given type.
+     *
+     * @tparam T: type of the policyElement. Policy Element supported are:
+     *                      - Strategy
+     *                      - Stream
+     *                      - InputSource
+     *                      - Usage.
+     */
+    struct collectionSupported;
+};
+
+template <>
+struct Collection<audio_stream_type_t>::collectionSupported {};
+template <>
+struct Collection<std::string>::collectionSupported {};
+template <>
+struct Collection<audio_usage_t>::collectionSupported {};
+template <>
+struct Collection<audio_source_t>::collectionSupported {};
+template <>
+struct Collection<routing_strategy>::collectionSupported {};
+
+typedef Collection<routing_strategy> StrategyCollection;
+typedef Collection<audio_stream_type_t> StreamCollection;
+typedef Collection<audio_usage_t> UsageCollection;
+typedef Collection<audio_source_t> InputSourceCollection;
+
+} // namespace audio_policy
+} // namespace android
diff --git a/services/audiopolicy/engineconfigurable/src/Element.h b/services/audiopolicy/engineconfigurable/src/Element.h
new file mode 100755
index 0000000..52e77e5
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Element.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <string>
+#include <utils/Errors.h>
+#include <system/audio.h>
+#include <utils/Log.h>
+
+namespace android
+{
+namespace audio_policy
+{
+
+template <typename Key>
+class Element
+{
+public:
+    Element(const std::string &name)
+        : mName(name)
+    {}
+    ~Element() {}
+
+    /**
+     * Returns identifier of this policy element
+     *
+     * @returns string representing the name of this policy element
+     */
+    const std::string &getName() const { return mName; }
+
+    /**
+    * Set the unique identifier for this policy element.
+    *
+    * @tparam Key type of the unique identifier.
+    * @param[in] identifier to be set.
+    *
+    * @return NO_ERROR if the identifier is valid and set correctly, error code otherwise.
+    */
+    status_t setIdentifier(Key identifier)
+    {
+        mIdentifier = identifier;
+        return NO_ERROR;
+    }
+
+    /**
+     * @return the unique identifier of this policy element.
+     */
+    const Key &getIdentifier() const { return mIdentifier; }
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     *
+     * @tparam Property for which this policy element has setter / getter.
+     * @return the property kept track by this policy base element.
+     */
+    template <typename Property>
+    Property get() const;
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     *
+     * @tparam Property for which this policy element has setter / getter.
+     *
+     * @param[in] property value to be assigned for this policy base element.
+     *
+     * @return the property kept track by this policy base element.
+     */
+    template <typename Property>
+    status_t set(Property property);
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Element(const Element &object);
+    Element &operator=(const Element &object);
+
+    std::string mName; /**< Unique literal Identifier of a policy base element*/
+    Key mIdentifier; /**< Unique numerical Identifier of a policy base element*/
+};
+} // namespace audio_policy
+} // namespace android
diff --git a/services/audiopolicy/engineconfigurable/src/Engine.cpp b/services/audiopolicy/engineconfigurable/src/Engine.cpp
new file mode 100755
index 0000000..61fae71
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Engine.cpp
@@ -0,0 +1,281 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "APM::AudioPolicyEngine"
+//#define LOG_NDEBUG 0
+
+//#define VERY_VERBOSE_LOGGING
+#ifdef VERY_VERBOSE_LOGGING
+#define ALOGVV ALOGV
+#else
+#define ALOGVV(a...) do { } while(0)
+#endif
+
+#include "Engine.h"
+#include "Strategy.h"
+#include "Stream.h"
+#include "InputSource.h"
+#include "Usage.h"
+#include <policy.h>
+#include <ParameterManagerWrapper.h>
+
+using std::string;
+using std::map;
+
+namespace android
+{
+namespace audio_policy
+{
+template <>
+StrategyCollection &Engine::getCollection<routing_strategy>()
+{
+    return mStrategyCollection;
+}
+template <>
+StreamCollection &Engine::getCollection<audio_stream_type_t>()
+{
+    return mStreamCollection;
+}
+template <>
+UsageCollection &Engine::getCollection<audio_usage_t>()
+{
+    return mUsageCollection;
+}
+template <>
+InputSourceCollection &Engine::getCollection<audio_source_t>()
+{
+    return mInputSourceCollection;
+}
+
+template <>
+const StrategyCollection &Engine::getCollection<routing_strategy>() const
+{
+    return mStrategyCollection;
+}
+template <>
+const StreamCollection &Engine::getCollection<audio_stream_type_t>() const
+{
+    return mStreamCollection;
+}
+template <>
+const UsageCollection &Engine::getCollection<audio_usage_t>() const
+{
+    return mUsageCollection;
+}
+template <>
+const InputSourceCollection &Engine::getCollection<audio_source_t>() const
+{
+    return mInputSourceCollection;
+}
+
+Engine::Engine()
+    : mManagerInterface(this),
+      mPluginInterface(this),
+      mPolicyParameterMgr(new ParameterManagerWrapper()),
+      mApmObserver(NULL)
+{
+    if (mPolicyParameterMgr->start() != NO_ERROR) {
+        ALOGE("%s: could not start Policy PFW", __FUNCTION__);
+        delete mPolicyParameterMgr;
+        mPolicyParameterMgr = NULL;
+    }
+}
+
+Engine::~Engine()
+{
+    mStrategyCollection.clear();
+    mStreamCollection.clear();
+    mInputSourceCollection.clear();
+    mUsageCollection.clear();
+}
+
+
+void Engine::setObserver(AudioPolicyManagerObserver *observer)
+{
+    ALOG_ASSERT(observer != NULL, "Invalid Audio Policy Manager observer");
+    mApmObserver = observer;
+}
+
+status_t Engine::initCheck()
+{
+    return (mPolicyParameterMgr != NULL) &&
+            mPolicyParameterMgr->isStarted() &&
+            (mApmObserver != NULL)?
+                NO_ERROR : NO_INIT;
+}
+
+bool Engine::setVolumeProfileForStream(const audio_stream_type_t &streamType,
+                                       Volume::device_category deviceCategory,
+                                       const VolumeCurvePoints &points)
+{
+    Stream *stream = getFromCollection<audio_stream_type_t>(streamType);
+    if (stream == NULL) {
+        ALOGE("%s: stream %d not found", __FUNCTION__, streamType);
+        return false;
+    }
+    return stream->setVolumeProfile(deviceCategory, points) == NO_ERROR;
+}
+
+template <typename Key>
+Element<Key> *Engine::getFromCollection(const Key &key) const
+{
+    const Collection<Key> collection = getCollection<Key>();
+    return collection.get(key);
+}
+
+template <typename Key>
+status_t Engine::add(const std::string &name, const Key &key)
+{
+    Collection<Key> &collection = getCollection<Key>();
+    return collection.add(name, key);
+}
+
+template <>
+routing_strategy Engine::getPropertyForKey<routing_strategy, audio_usage_t>(audio_usage_t usage) const
+{
+    const SwAudioOutputCollection &outputs = mApmObserver->getOutputs();
+
+    if (usage == AUDIO_USAGE_ASSISTANCE_ACCESSIBILITY &&
+            (outputs.isStreamActive(AUDIO_STREAM_RING) ||
+             outputs.isStreamActive(AUDIO_STREAM_ALARM))) {
+        return STRATEGY_SONIFICATION;
+    }
+    return getPropertyForKey<routing_strategy, audio_usage_t>(usage);
+}
+
+template <typename Property, typename Key>
+Property Engine::getPropertyForKey(Key key) const
+{
+    Element<Key> *element = getFromCollection<Key>(key);
+    if (element == NULL) {
+        ALOGE("%s: Element not found within collection", __FUNCTION__);
+        return static_cast<Property>(0);
+    }
+    return element->template get<Property>();
+}
+
+template <>
+audio_devices_t Engine::getPropertyForKey<audio_devices_t, routing_strategy>(routing_strategy strategy) const
+{
+    const SwAudioOutputCollection &outputs = mApmObserver->getOutputs();
+
+    /** This is the only case handled programmatically because the PFW is unable to know the
+     * activity of streams.
+     *
+     * -While media is playing on a remote device, use the the sonification behavior.
+     * Note that we test this usecase before testing if media is playing because
+     * the isStreamActive() method only informs about the activity of a stream, not
+     * if it's for local playback. Note also that we use the same delay between both tests
+     *
+     * -When media is not playing anymore, fall back on the sonification behavior
+     */
+    if (strategy == STRATEGY_SONIFICATION_RESPECTFUL &&
+            !is_state_in_call(getPhoneState()) &&
+            !outputs.isStreamActiveRemotely(AUDIO_STREAM_MUSIC,
+                                    SONIFICATION_RESPECTFUL_AFTER_MUSIC_DELAY) &&
+            outputs.isStreamActive(AUDIO_STREAM_MUSIC, SONIFICATION_RESPECTFUL_AFTER_MUSIC_DELAY)) {
+        return getPropertyForKey<audio_devices_t, routing_strategy>(STRATEGY_MEDIA);
+    }
+    return getPropertyForKey<audio_devices_t, routing_strategy>(strategy);
+}
+
+routing_strategy Engine::ManagerInterfaceImpl::getStrategyForUsage(audio_usage_t usage)
+{
+    return mPolicyEngine->getPropertyForKey<routing_strategy, audio_usage_t>(usage);
+}
+
+audio_devices_t Engine::ManagerInterfaceImpl::getDeviceForStrategy(routing_strategy stategy) const
+{
+    return mPolicyEngine->getPropertyForKey<audio_devices_t, routing_strategy>(stategy);
+}
+
+template <typename Property, typename Key>
+bool Engine::setPropertyForKey(const Property &property, const Key &key)
+{
+    Element<Key> *element = getFromCollection<Key>(key);
+    if (element == NULL) {
+        ALOGE("%s: Element not found within collection", __FUNCTION__);
+        return BAD_VALUE;
+    }
+    return element->template set<Property>(property) == NO_ERROR;
+}
+
+float Engine::volIndexToDb(Volume::device_category category,
+                             audio_stream_type_t streamType,
+                             int indexInUi)
+{
+    Stream *stream = getFromCollection<audio_stream_type_t>(streamType);
+    if (stream == NULL) {
+        ALOGE("%s: Element indexed by key=%d not found", __FUNCTION__, streamType);
+        return 1.0f;
+    }
+    return stream->volIndexToDb(category, indexInUi);
+}
+
+status_t Engine::initStreamVolume(audio_stream_type_t streamType,
+                                           int indexMin, int indexMax)
+{
+    Stream *stream = getFromCollection<audio_stream_type_t>(streamType);
+    if (stream == NULL) {
+        ALOGE("%s: Stream Type %d not found", __FUNCTION__, streamType);
+        return BAD_TYPE;
+    }
+    return stream->initVolume(indexMin, indexMax);
+}
+
+status_t Engine::setPhoneState(audio_mode_t mode)
+{
+    return mPolicyParameterMgr->setPhoneState(mode);
+}
+
+audio_mode_t Engine::getPhoneState() const
+{
+    return mPolicyParameterMgr->getPhoneState();
+}
+
+status_t Engine::setForceUse(audio_policy_force_use_t usage,
+                                      audio_policy_forced_cfg_t config)
+{
+    return mPolicyParameterMgr->setForceUse(usage, config);
+}
+
+audio_policy_forced_cfg_t Engine::getForceUse(audio_policy_force_use_t usage) const
+{
+    return mPolicyParameterMgr->getForceUse(usage);
+}
+
+status_t Engine::setDeviceConnectionState(audio_devices_t devices, audio_policy_dev_state_t state,
+                                          const char *deviceAddress)
+{
+    return mPolicyParameterMgr->setDeviceConnectionState(devices, state, deviceAddress);
+}
+
+template <>
+AudioPolicyManagerInterface *Engine::queryInterface()
+{
+    return &mManagerInterface;
+}
+
+template <>
+AudioPolicyPluginInterface *Engine::queryInterface()
+{
+    return &mPluginInterface;
+}
+
+} // namespace audio_policy
+} // namespace android
+
+
diff --git a/services/audiopolicy/engineconfigurable/src/Engine.h b/services/audiopolicy/engineconfigurable/src/Engine.h
new file mode 100755
index 0000000..6fa7a13
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Engine.h
@@ -0,0 +1,225 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+
+#include <AudioPolicyManagerInterface.h>
+#include <AudioPolicyPluginInterface.h>
+#include "Collection.h"
+
+namespace android
+{
+class AudioPolicyManagerObserver;
+
+namespace audio_policy
+{
+
+class ParameterManagerWrapper;
+class VolumeProfile;
+
+class Engine
+{
+public:
+    Engine();
+    virtual ~Engine();
+
+    template <class RequestedInterface>
+    RequestedInterface *queryInterface();
+
+private:
+    /// Interface members
+    class ManagerInterfaceImpl : public AudioPolicyManagerInterface
+    {
+    public:
+        ManagerInterfaceImpl(Engine *policyEngine)
+            : mPolicyEngine(policyEngine) {}
+
+        virtual android::status_t initCheck()
+        {
+            return mPolicyEngine->initCheck();
+        }
+        virtual void setObserver(AudioPolicyManagerObserver *observer)
+        {
+            mPolicyEngine->setObserver(observer);
+        }
+        virtual audio_devices_t getDeviceForInputSource(audio_source_t inputSource) const
+        {
+            return mPolicyEngine->getPropertyForKey<audio_devices_t, audio_source_t>(inputSource);
+        }
+        virtual audio_devices_t getDeviceForStrategy(routing_strategy stategy) const;
+        virtual routing_strategy getStrategyForStream(audio_stream_type_t stream)
+        {
+            return mPolicyEngine->getPropertyForKey<routing_strategy, audio_stream_type_t>(stream);
+        }
+        virtual routing_strategy getStrategyForUsage(audio_usage_t usage);
+        virtual status_t setPhoneState(audio_mode_t mode)
+        {
+            return mPolicyEngine->setPhoneState(mode);
+        }
+        virtual audio_mode_t getPhoneState() const
+        {
+            return mPolicyEngine->getPhoneState();
+        }
+        virtual status_t setForceUse(audio_policy_force_use_t usage,
+                                              audio_policy_forced_cfg_t config)
+        {
+            return mPolicyEngine->setForceUse(usage, config);
+        }
+        virtual audio_policy_forced_cfg_t getForceUse(audio_policy_force_use_t usage) const
+        {
+            return mPolicyEngine->getForceUse(usage);
+        }
+        virtual android::status_t setDeviceConnectionState(const sp<DeviceDescriptor> devDesc,
+                                                           audio_policy_dev_state_t state)
+        {
+            return mPolicyEngine->setDeviceConnectionState(devDesc->type(), state,
+                                                           devDesc->mAddress);
+        }
+        virtual status_t initStreamVolume(audio_stream_type_t stream,
+                                                   int indexMin, int indexMax)
+        {
+            return mPolicyEngine->initStreamVolume(stream, indexMin, indexMax);
+        }
+
+        virtual void initializeVolumeCurves(bool /*isSpeakerDrcEnabled*/) {}
+
+        virtual float volIndexToDb(Volume::device_category deviceCategory,
+                                     audio_stream_type_t stream,
+                                     int indexInUi)
+        {
+            return mPolicyEngine->volIndexToDb(deviceCategory, stream, indexInUi);
+        }
+
+    private:
+        Engine *mPolicyEngine;
+    } mManagerInterface;
+
+    class PluginInterfaceImpl : public AudioPolicyPluginInterface
+    {
+    public:
+        PluginInterfaceImpl(Engine *policyEngine)
+            : mPolicyEngine(policyEngine) {}
+
+        virtual status_t addStrategy(const std::string &name, routing_strategy strategy)
+        {
+            return mPolicyEngine->add<routing_strategy>(name, strategy);
+        }
+        virtual status_t addStream(const std::string &name, audio_stream_type_t stream)
+        {
+            return mPolicyEngine->add<audio_stream_type_t>(name, stream);
+        }
+        virtual status_t addUsage(const std::string &name, audio_usage_t usage)
+        {
+            return mPolicyEngine->add<audio_usage_t>(name, usage);
+        }
+        virtual status_t addInputSource(const std::string &name, audio_source_t source)
+        {
+            return mPolicyEngine->add<audio_source_t>(name, source);
+        }
+        virtual bool setDeviceForStrategy(const routing_strategy &strategy, audio_devices_t devices)
+        {
+            return mPolicyEngine->setPropertyForKey<audio_devices_t, routing_strategy>(devices,
+                                                                                       strategy);
+        }
+        virtual bool setStrategyForStream(const audio_stream_type_t &stream,
+                                          routing_strategy strategy)
+        {
+            return mPolicyEngine->setPropertyForKey<routing_strategy, audio_stream_type_t>(strategy,
+                                                                                           stream);
+        }
+        virtual bool setVolumeProfileForStream(const audio_stream_type_t &stream,
+                                               Volume::device_category deviceCategory,
+                                               const VolumeCurvePoints &points)
+        {
+            return mPolicyEngine->setVolumeProfileForStream(stream, deviceCategory, points);
+        }
+
+        virtual bool setStrategyForUsage(const audio_usage_t &usage, routing_strategy strategy)
+        {
+            return mPolicyEngine->setPropertyForKey<routing_strategy, audio_usage_t>(strategy,
+                                                                                     usage);
+        }
+        virtual bool setDeviceForInputSource(const audio_source_t &inputSource,
+                                             audio_devices_t device)
+        {
+            return mPolicyEngine->setPropertyForKey<audio_devices_t, audio_source_t>(device,
+                                                                                     inputSource);
+        }
+
+    private:
+        Engine *mPolicyEngine;
+    } mPluginInterface;
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Engine(const Engine &object);
+    Engine &operator=(const Engine &object);
+
+    void setObserver(AudioPolicyManagerObserver *observer);
+
+    bool setVolumeProfileForStream(const audio_stream_type_t &stream,
+                                   Volume::device_category deviceCategory,
+                                   const VolumeCurvePoints &points);
+
+    status_t initCheck();
+    status_t setPhoneState(audio_mode_t mode);
+    audio_mode_t getPhoneState() const;
+    status_t setForceUse(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config);
+    audio_policy_forced_cfg_t getForceUse(audio_policy_force_use_t usage) const;
+    status_t setDeviceConnectionState(audio_devices_t devices, audio_policy_dev_state_t state,
+                                      const char *deviceAddress);
+
+    float volIndexToDb(Volume::device_category category,
+                       audio_stream_type_t stream,
+                       int indexInUi);
+    status_t initStreamVolume(audio_stream_type_t stream, int indexMin, int indexMax);
+
+    StrategyCollection mStrategyCollection; /**< Strategies indexed by their enum id. */
+    StreamCollection mStreamCollection; /**< Streams indexed by their enum id.  */
+    UsageCollection mUsageCollection; /**< Usages indexed by their enum id. */
+    InputSourceCollection mInputSourceCollection; /**< Input sources indexed by their enum id. */
+
+    template <typename Key>
+    status_t add(const std::string &name, const Key &key);
+
+    template <typename Key>
+    Element<Key> *getFromCollection(const Key &key) const;
+
+    template <typename Key>
+    const Collection<Key> &getCollection() const;
+
+    template <typename Key>
+    Collection<Key> &getCollection();
+
+    template <typename Property, typename Key>
+    Property getPropertyForKey(Key key) const;
+
+    template <typename Property, typename Key>
+    bool setPropertyForKey(const Property &property, const Key &key);
+
+    /**
+     * Policy Parameter Manager hidden through a wrapper.
+     */
+    ParameterManagerWrapper *mPolicyParameterMgr;
+
+    AudioPolicyManagerObserver *mApmObserver;
+};
+
+}; // namespace audio_policy
+
+}; // namespace android
+
diff --git a/services/audiopolicy/engineconfigurable/src/EngineInstance.cpp b/services/audiopolicy/engineconfigurable/src/EngineInstance.cpp
new file mode 100755
index 0000000..9aa89b2
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/EngineInstance.cpp
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include <AudioPolicyManagerInterface.h>
+#include <AudioPolicyPluginInterface.h>
+#include "AudioPolicyEngineInstance.h"
+#include "Engine.h"
+
+using std::string;
+
+namespace android
+{
+namespace audio_policy
+{
+
+EngineInstance::EngineInstance()
+{
+}
+
+EngineInstance *EngineInstance::getInstance()
+{
+    static EngineInstance instance;
+    return &instance;
+}
+
+EngineInstance::~EngineInstance()
+{
+}
+
+Engine *EngineInstance::getEngine() const
+{
+    static Engine engine;
+    return &engine;
+}
+
+template <>
+AudioPolicyManagerInterface *EngineInstance::queryInterface() const
+{
+    return getEngine()->queryInterface<AudioPolicyManagerInterface>();
+}
+
+template <>
+AudioPolicyPluginInterface *EngineInstance::queryInterface() const
+{
+    return getEngine()->queryInterface<AudioPolicyPluginInterface>();
+}
+
+} // namespace audio_policy
+} // namespace android
+
diff --git a/services/audiopolicy/engineconfigurable/src/InputSource.cpp b/services/audiopolicy/engineconfigurable/src/InputSource.cpp
new file mode 100755
index 0000000..9ff1538
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/InputSource.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "APM::AudioPolicyEngine/InputSource"
+
+#include "InputSource.h"
+
+using std::string;
+
+namespace android
+{
+namespace audio_policy
+{
+status_t Element<audio_source_t>::setIdentifier(audio_source_t identifier)
+{
+    if (identifier > AUDIO_SOURCE_MAX && identifier != AUDIO_SOURCE_HOTWORD) {
+        return BAD_VALUE;
+    }
+    mIdentifier = identifier;
+    ALOGD("%s: InputSource %s identifier 0x%X", __FUNCTION__, getName().c_str(), identifier);
+    return NO_ERROR;
+}
+
+/**
+* Set the device associated to this source.
+* It checks if the input device is valid but allows to set a NONE device
+* (i.e. only the IN BIT is set).
+*
+* @param[in] devices selected for the given input source.
+* @tparam audio_devices_t: Applicable input device for this input source.
+*
+* @return NO_ERROR if the device is either valid or none, error code otherwise.
+*/
+template <>
+status_t Element<audio_source_t>::set(audio_devices_t devices)
+{
+    if (!audio_is_input_device(devices) && devices != AUDIO_DEVICE_BIT_IN) {
+        ALOGE("%s: trying to set an invalid device 0x%X for input source %s",
+              __FUNCTION__, devices, getName().c_str());
+        return BAD_VALUE;
+    }
+    ALOGD("%s: 0x%X for input source %s", __FUNCTION__, devices, getName().c_str());
+    mApplicableDevices = devices;
+    return NO_ERROR;
+}
+
+template <>
+audio_devices_t Element<audio_source_t>::get<audio_devices_t>() const
+{
+    ALOGV("%s: 0x%X for inputSource %s", __FUNCTION__, mApplicableDevices, getName().c_str());
+    return mApplicableDevices;
+}
+} // namespace audio_policy
+} // namespace android
+
+
diff --git a/services/audiopolicy/engineconfigurable/src/InputSource.h b/services/audiopolicy/engineconfigurable/src/InputSource.h
new file mode 100755
index 0000000..6c498dc
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/InputSource.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include "Element.h"
+
+namespace android
+{
+namespace audio_policy
+{
+
+/**
+ * Specialization of policy base class element for audio_source_t
+ * @tparam audio_source_t Policy Base Element identified by the audio_source_t definition.
+ */
+template <>
+class Element<audio_source_t>
+{
+public:
+    Element(const std::string &name)
+        : mName(name),
+          mApplicableDevices(AUDIO_DEVICE_NONE)
+    {}
+    ~Element() {}
+
+    /**
+     * Returns identifier of this policy element
+     *
+     * @returns string representing the name of this policy element
+     */
+    const std::string &getName() const { return mName; }
+
+    /**
+    * Set the unique identifier for this policy element.
+    *
+    * @tparam Key type of the unique identifier.
+    * @param[in] identifier to be set.
+    *
+    * @return NO_ERROR if the identifier is valid and set correctly, error code otherwise.
+    */
+    status_t setIdentifier(audio_source_t identifier);
+
+    /**
+     * @return the unique identifier of this policy element.
+     */
+    audio_source_t getIdentifier() const { return mIdentifier; }
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     */
+    template <typename Property>
+    Property get() const;
+
+    template <typename Property>
+    status_t set(Property property);
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Element(const Element &object);
+    Element &operator=(const Element &object);
+
+    std::string mName; /**< Unique literal Identifier of a policy base element*/
+    audio_source_t mIdentifier; /**< Unique numerical Identifier of a policy base element*/
+
+    audio_devices_t mApplicableDevices; /**< Applicable input device for this input source. */
+};
+
+typedef Element<audio_source_t> InputSource;
+
+} // namespace audio_policy
+} // namespace android
+
diff --git a/services/audiopolicy/engineconfigurable/src/Strategy.cpp b/services/audiopolicy/engineconfigurable/src/Strategy.cpp
new file mode 100755
index 0000000..847443a
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Strategy.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "APM::AudioPolicyEngine/Strategy"
+
+#include "Strategy.h"
+
+using std::string;
+
+namespace android
+{
+namespace audio_policy
+{
+
+status_t Element<routing_strategy>::setIdentifier(routing_strategy identifier)
+{
+    if (identifier >= NUM_STRATEGIES) {
+        return BAD_VALUE;
+    }
+    mIdentifier = identifier;
+    ALOGD("%s: Strategy %s identifier 0x%X", __FUNCTION__, getName().c_str(), identifier);
+    return NO_ERROR;
+}
+
+/**
+ * Set the device associated to this strategy.
+ * It checks if the output device is valid but allows to set a NONE device
+ *
+ * @param[in] devices selected for the given strategy.
+ *
+ * @return NO_ERROR if the device is either valid or none, error code otherwise.
+ */
+template <>
+status_t Element<routing_strategy>::set<audio_devices_t>(audio_devices_t devices)
+{
+    if (!audio_is_output_devices(devices) && devices != AUDIO_DEVICE_NONE) {
+        ALOGE("%s: trying to set an invalid device 0x%X for strategy %s",
+              __FUNCTION__, devices, getName().c_str());
+        return BAD_VALUE;
+    }
+    ALOGD("%s: 0x%X for strategy %s", __FUNCTION__, devices, getName().c_str());
+    mApplicableDevices = devices;
+    return NO_ERROR;
+}
+
+template <>
+audio_devices_t Element<routing_strategy>::get<audio_devices_t>() const
+{
+    ALOGV("%s: 0x%X for strategy %s", __FUNCTION__, mApplicableDevices, getName().c_str());
+    return mApplicableDevices;
+}
+
+} // namespace audio_policy
+} // namespace android
+
diff --git a/services/audiopolicy/engineconfigurable/src/Strategy.h b/services/audiopolicy/engineconfigurable/src/Strategy.h
new file mode 100755
index 0000000..1157d55
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Strategy.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include "Element.h"
+#include <RoutingStrategy.h>
+
+namespace android
+{
+namespace audio_policy
+{
+
+/**
+ * @tparam audio_devices_t: Applicable output device(s) for this strategy.
+ */
+template <>
+class Element<routing_strategy>
+{
+public:
+    Element(const std::string &name)
+        : mName(name),
+          mApplicableDevices(AUDIO_DEVICE_NONE)
+    {}
+    ~Element() {}
+
+    /**
+     * Returns identifier of this policy element
+     *
+     * @returns string representing the name of this policy element
+     */
+    const std::string &getName() const { return mName; }
+
+    /**
+    * Set the unique identifier for this policy element.
+    *
+    * @tparam Key type of the unique identifier.
+    * @param[in] identifier to be set.
+    *
+    * @return NO_ERROR if the identifier is valid and set correctly, error code otherwise.
+    */
+    status_t setIdentifier(routing_strategy identifier);
+
+    /**
+     * @return the unique identifier of this policy element.
+     */
+    routing_strategy getIdentifier() const { return mIdentifier; }
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     */
+    template <typename Property>
+    Property get() const;
+
+    template <typename Property>
+    status_t set(Property property);
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Element(const Element &object);
+    Element &operator=(const Element &object);
+
+    std::string mName; /**< Unique literal Identifier of a policy base element*/
+    routing_strategy mIdentifier; /**< Unique numerical Identifier of a policy base element*/
+
+    audio_devices_t mApplicableDevices; /**< Applicable output device(s) for this strategy. */
+};
+
+typedef Element<routing_strategy> Strategy;
+
+} // namespace audio_policy
+} // namespace android
+
+
diff --git a/services/audiopolicy/engineconfigurable/src/Stream.cpp b/services/audiopolicy/engineconfigurable/src/Stream.cpp
new file mode 100755
index 0000000..bea2c19
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Stream.cpp
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "APM::AudioPolicyEngine/Stream"
+
+#include "Stream.h"
+#include <system/audio.h>
+
+using std::string;
+
+namespace android
+{
+namespace audio_policy
+{
+
+status_t Element<audio_stream_type_t>::setIdentifier(audio_stream_type_t identifier)
+{
+    if (identifier > AUDIO_STREAM_CNT) {
+        return BAD_VALUE;
+    }
+    mIdentifier = identifier;
+    ALOGD("%s: Stream %s identifier 0x%X", __FUNCTION__, getName().c_str(), identifier);
+    return NO_ERROR;
+}
+
+/**
+* Set the strategy to follow for this stream.
+* It checks if the strategy is valid.
+*
+* @param[in] strategy to be followed.
+*
+* @return NO_ERROR if the strategy is set correctly, error code otherwise.
+*/
+template <>
+status_t Element<audio_stream_type_t>::set<routing_strategy>(routing_strategy strategy)
+{
+    if (strategy >= NUM_STRATEGIES) {
+        return BAD_VALUE;
+    }
+    mApplicableStrategy = strategy;
+    ALOGD("%s: 0x%X for Stream %s", __FUNCTION__, strategy, getName().c_str());
+    return NO_ERROR;
+}
+
+template <>
+routing_strategy Element<audio_stream_type_t>::get<routing_strategy>() const
+{
+    ALOGV("%s: 0x%X for Stream %s", __FUNCTION__, mApplicableStrategy, getName().c_str());
+    return mApplicableStrategy;
+}
+
+status_t Element<audio_stream_type_t>::setVolumeProfile(Volume::device_category category,
+                                                        const VolumeCurvePoints &points)
+{
+    ALOGD("%s: adding volume profile for %s for device category %d, points nb =%d", __FUNCTION__,
+          getName().c_str(), category, points.size());
+    mVolumeProfiles[category] = points;
+
+    for (size_t i = 0; i < points.size(); i++) {
+        ALOGV("%s: %s cat=%d curve index =%d Index=%d dBAttenuation=%f",
+              __FUNCTION__, getName().c_str(), category, i, points[i].mIndex,
+             points[i].mDBAttenuation);
+    }
+    return NO_ERROR;
+}
+
+status_t Element<audio_stream_type_t>::initVolume(int indexMin, int indexMax)
+{
+    ALOGV("initStreamVolume() stream %s, min %d, max %d", getName().c_str(), indexMin, indexMax);
+    if (indexMin < 0 || indexMin >= indexMax) {
+        ALOGW("initStreamVolume() invalid index limits for stream %s, min %d, max %d",
+              getName().c_str(), indexMin, indexMax);
+        return BAD_VALUE;
+    }
+    mIndexMin = indexMin;
+    mIndexMax = indexMax;
+
+    return NO_ERROR;
+}
+
+float Element<audio_stream_type_t>::volIndexToDb(Volume::device_category deviceCategory,
+                                                   int indexInUi)
+{
+    VolumeProfileConstIterator it = mVolumeProfiles.find(deviceCategory);
+    if (it == mVolumeProfiles.end()) {
+        ALOGE("%s: device category %d not found for stream %s", __FUNCTION__, deviceCategory,
+              getName().c_str());
+        return 1.0f;
+    }
+    const VolumeCurvePoints curve = mVolumeProfiles[deviceCategory];
+    if (curve.size() != Volume::VOLCNT) {
+        ALOGE("%s: invalid profile for category %d and for stream %s", __FUNCTION__, deviceCategory,
+              getName().c_str());
+        return 1.0f;
+    }
+
+    // the volume index in the UI is relative to the min and max volume indices for this stream type
+    int nbSteps = 1 + curve[Volume::VOLMAX].mIndex -
+            curve[Volume::VOLMIN].mIndex;
+
+    if (mIndexMax - mIndexMin == 0) {
+        ALOGE("%s: Invalid volume indexes Min=Max=%d", __FUNCTION__, mIndexMin);
+        return 1.0f;
+    }
+    int volIdx = (nbSteps * (indexInUi - mIndexMin)) /
+            (mIndexMax - mIndexMin);
+
+    // find what part of the curve this index volume belongs to, or if it's out of bounds
+    int segment = 0;
+    if (volIdx < curve[Volume::VOLMIN].mIndex) {         // out of bounds
+        return 0.0f;
+    } else if (volIdx < curve[Volume::VOLKNEE1].mIndex) {
+        segment = 0;
+    } else if (volIdx < curve[Volume::VOLKNEE2].mIndex) {
+        segment = 1;
+    } else if (volIdx <= curve[Volume::VOLMAX].mIndex) {
+        segment = 2;
+    } else {                                                               // out of bounds
+        return 1.0f;
+    }
+
+    // linear interpolation in the attenuation table in dB
+    float decibels = curve[segment].mDBAttenuation +
+            ((float)(volIdx - curve[segment].mIndex)) *
+                ( (curve[segment+1].mDBAttenuation -
+                        curve[segment].mDBAttenuation) /
+                    ((float)(curve[segment+1].mIndex -
+                            curve[segment].mIndex)) );
+
+    ALOGV("VOLUME vol index=[%d %d %d], dB=[%.1f %.1f %.1f]",
+            curve[segment].mIndex, volIdx,
+            curve[segment+1].mIndex,
+            curve[segment].mDBAttenuation,
+            decibels,
+            curve[segment+1].mDBAttenuation);
+
+    return decibels;
+}
+
+} // namespace audio_policy
+} // namespace android
+
diff --git a/services/audiopolicy/engineconfigurable/src/Stream.h b/services/audiopolicy/engineconfigurable/src/Stream.h
new file mode 100755
index 0000000..8c39dc6
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Stream.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include "Element.h"
+#include "EngineDefinition.h"
+#include <Volume.h>
+#include <RoutingStrategy.h>
+#include <map>
+
+namespace android
+{
+namespace audio_policy
+{
+/**
+ * @tparam routing_strategy: Applicable strategy for this stream.
+ */
+template <>
+class Element<audio_stream_type_t>
+{
+private:
+    typedef std::map<Volume::device_category, VolumeCurvePoints> VolumeProfiles;
+    typedef VolumeProfiles::iterator VolumeProfileIterator;
+    typedef VolumeProfiles::const_iterator VolumeProfileConstIterator;
+
+public:
+    Element(const std::string &name)
+        : mName(name),
+          mApplicableStrategy(STRATEGY_MEDIA),
+          mIndexMin(0),
+          mIndexMax(1)
+    {}
+    ~Element() {}
+
+    /**
+     * Returns identifier of this policy element
+     *
+     * @returns string representing the name of this policy element
+     */
+    const std::string &getName() const { return mName; }
+
+    /**
+    * Set the unique identifier for this policy element.
+    *
+    * @tparam Key type of the unique identifier.
+    * @param[in] identifier to be set.
+    *
+    * @return NO_ERROR if the identifier is valid and set correctly, error code otherwise.
+    */
+    status_t setIdentifier(audio_stream_type_t identifier);
+
+    /**
+     * @return the unique identifier of this policy element.
+     */
+    audio_stream_type_t getIdentifier() const { return mIdentifier; }
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     */
+    template <typename Property>
+    Property get() const;
+
+    template <typename Property>
+    status_t set(Property property);
+
+    status_t setVolumeProfile(Volume::device_category category, const VolumeCurvePoints &points);
+
+    float volIndexToDb(Volume::device_category deviceCategory, int indexInUi);
+
+    status_t initVolume(int indexMin, int indexMax);
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Element(const Element &object);
+    Element &operator=(const Element &object);
+
+    std::string mName; /**< Unique literal Identifier of a policy base element*/
+    audio_stream_type_t mIdentifier; /**< Unique numerical Identifier of a policy base element*/
+
+    routing_strategy mApplicableStrategy; /**< Applicable strategy for this stream. */
+
+    /**
+     * Collection of volume profiles indexed by the stream type.
+     * Volume is the only reason why the stream profile was not removed from policy when introducing
+     * attributes.
+     */
+    VolumeProfiles mVolumeProfiles;
+
+    int mIndexMin;
+
+    int mIndexMax;
+};
+
+typedef Element<audio_stream_type_t> Stream;
+
+} // namespace audio_policy
+} // namespace android
+
+
diff --git a/services/audiopolicy/engineconfigurable/src/Usage.cpp b/services/audiopolicy/engineconfigurable/src/Usage.cpp
new file mode 100755
index 0000000..5d20828
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Usage.cpp
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "APM::AudioPolicyEngine/Usage"
+
+#include "Usage.h"
+
+namespace android
+{
+namespace audio_policy
+{
+
+status_t Element<audio_usage_t>::setIdentifier(audio_usage_t identifier)
+{
+    if (identifier > AUDIO_USAGE_MAX) {
+        return BAD_VALUE;
+    }
+    mIdentifier = identifier;
+    ALOGD("%s: Usage %s has identifier 0x%X", __FUNCTION__, getName().c_str(), identifier);
+    return NO_ERROR;
+}
+
+template <>
+status_t Element<audio_usage_t>::set<routing_strategy>(routing_strategy strategy)
+{
+    if (strategy >= NUM_STRATEGIES) {
+        return BAD_VALUE;
+    }
+    ALOGD("%s: %d for Usage %s", __FUNCTION__, strategy, getName().c_str());
+    mApplicableStrategy = strategy;
+    return NO_ERROR;
+}
+
+template <>
+routing_strategy Element<audio_usage_t>::get<routing_strategy>() const
+{
+    ALOGD("%s: %d for Usage %s", __FUNCTION__, mApplicableStrategy, getName().c_str());
+    return mApplicableStrategy;
+}
+
+} // namespace audio_policy
+} // namespace android
+
+
diff --git a/services/audiopolicy/engineconfigurable/src/Usage.h b/services/audiopolicy/engineconfigurable/src/Usage.h
new file mode 100755
index 0000000..d69e0e0
--- /dev/null
+++ b/services/audiopolicy/engineconfigurable/src/Usage.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#pragma once
+
+#include "Element.h"
+#include <RoutingStrategy.h>
+
+namespace android
+{
+namespace audio_policy
+{
+
+/**
+ * @tparam routing_strategy: Applicable strategy for this usage.
+ */
+template <>
+class Element<audio_usage_t>
+{
+public:
+    Element(const std::string &name)
+        : mName(name),
+          mApplicableStrategy(STRATEGY_MEDIA)
+    {}
+    ~Element() {}
+
+    /**
+     * Returns identifier of this policy element
+     *
+     * @returns string representing the name of this policy element
+     */
+    const std::string &getName() const { return mName; }
+
+    /**
+    * Set the unique identifier for this policy element.
+    *
+    * @tparam Key type of the unique identifier.
+    * @param[in] identifier to be set.
+    *
+    * @return NO_ERROR if the identifier is valid and set correctly, error code otherwise.
+    */
+    status_t setIdentifier(audio_usage_t identifier);
+
+    /**
+     * @return the unique identifier of this policy element.
+     */
+    audio_usage_t getIdentifier() const { return mIdentifier; }
+
+    /**
+     * A Policy element may implement getter/setter function for a given property.
+     * Property may be routing_strategy, audio_stream_type_t, audio_usage_t, audio_source_t
+     * or a string.
+     */
+    template <typename Property>
+    Property get() const;
+
+    template <typename Property>
+    status_t set(Property property);
+
+private:
+    /* Copy facilities are put private to disable copy. */
+    Element(const Element &object);
+    Element &operator=(const Element &object);
+
+    std::string mName; /**< Unique literal Identifier of a policy base element*/
+    audio_usage_t mIdentifier; /**< Unique numerical Identifier of a policy base element*/
+    routing_strategy mApplicableStrategy; /**< Applicable strategy for this usage. */
+};
+
+typedef Element<audio_usage_t> Usage;
+
+} // namespace audio_policy
+} // namespace android
+
+