Bluetooth HID Device API docs and helper

* Add a builder for BluetoothHidDeviceAppQosSettings
* Add documentation for BluetoothHidDeviceAppSdpSettings
and BluetoothHidDeviceAppQosSettings
* Fix the behavior of and BluetoothHidDeviceAppSdpSettings.equals()
and BluetoothHidDeviceAppQosSettings.equals()

Bug: 63384609
Test: test with HID device apps
Change-Id: I933f4ec3034e1f704ddd614e48b76d27fda8b6ff
diff --git a/core/java/android/bluetooth/BluetoothHidDevice.java b/core/java/android/bluetooth/BluetoothHidDevice.java
index e3d763a..6692e13 100644
--- a/core/java/android/bluetooth/BluetoothHidDevice.java
+++ b/core/java/android/bluetooth/BluetoothHidDevice.java
@@ -350,13 +350,22 @@
      * application can be registered at time. When no longer used, application
      * should be unregistered using
      * {@link #unregisterApp(BluetoothHidDeviceAppConfiguration)}.
+     * The registration status should be tracked by the application by handling callback from
+     * BluetoothHidDeviceCallback#onAppStatusChanged. The app registration status is not related
+     * to the return value of this method.
      *
      * @param sdp {@link BluetoothHidDeviceAppSdpSettings} object of HID Device SDP record.
+     * The HID Device SDP record is required.
      * @param inQos {@link BluetoothHidDeviceAppQosSettings} object of Incoming QoS Settings.
+     * The Incoming QoS Settings is not required. Use null or default
+     * BluetoothHidDeviceAppQosSettings.Builder for default values.
      * @param outQos {@link BluetoothHidDeviceAppQosSettings} object of Outgoing QoS Settings.
+     * The Outgoing QoS Settings is not required. Use null or default
+     * BluetoothHidDeviceAppQosSettings.Builder for default values.
      * @param callback {@link BluetoothHidDeviceCallback} object to which callback messages will be
      * sent.
-     * @return
+     * The BluetoothHidDeviceCallback object is required.
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean registerApp(BluetoothHidDeviceAppSdpSettings sdp,
             BluetoothHidDeviceAppQosSettings inQos, BluetoothHidDeviceAppQosSettings outQos,
@@ -394,12 +403,15 @@
      * {@link #registerApp
      * (BluetoothHidDeviceAppQosSettings, BluetoothHidDeviceAppQosSettings,
      * BluetoothHidDeviceAppQosSettings, BluetoothHidDeviceCallback)}
+     * The registration status should be tracked by the application by handling callback from
+     * BluetoothHidDeviceCallback#onAppStatusChanged. The app registration status is not related
+     * to the return value of this method.
      *
      * @param config {@link BluetoothHidDeviceAppConfiguration} object as obtained from {@link
      * BluetoothHidDeviceCallback#onAppStatusChanged(BluetoothDevice,
      * BluetoothHidDeviceAppConfiguration,
      * boolean)}
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean unregisterApp(BluetoothHidDeviceAppConfiguration config) {
         Log.v(TAG, "unregisterApp()");
@@ -426,7 +438,7 @@
      * @param id Report Id, as defined in descriptor. Can be 0 in case Report Id are not defined in
      * descriptor.
      * @param data Report data, not including Report Id.
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean sendReport(BluetoothDevice device, int id, byte[] data) {
         boolean result = false;
@@ -452,7 +464,7 @@
      * @param type Report Type, as in request.
      * @param id Report Id, as in request.
      * @param data Report data, not including Report Id.
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean replyReport(BluetoothDevice device, byte type, byte id, byte[] data) {
         Log.v(TAG, "replyReport(): device=" + device + " type=" + type + " id=" + id);
@@ -478,7 +490,7 @@
      * from {@link BluetoothHidDeviceCallback#onSetReport(BluetoothDevice, byte, byte, byte[])}.
      *
      * @param error Error to be sent for SET_REPORT via HANDSHAKE.
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean reportError(BluetoothDevice device, byte error) {
         Log.v(TAG, "reportError(): device=" + device + " error=" + error);
@@ -524,10 +536,13 @@
     }
 
     /**
-     * Initiates connection to host which currently has Virtual Cable
-     * established with device.
+     * Initiates connection to host which is currently paired with this device.
+     * If the application is not registered, #connect(BluetoothDevice) will fail.
+     * The connection state should be tracked by the application by handling callback from
+     * BluetoothHidDeviceCallback#onConnectionStateChanged. The connection state is not related
+     * to the return value of this method.
      *
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean connect(BluetoothDevice device) {
         Log.v(TAG, "connect(): device=" + device);
@@ -550,8 +565,11 @@
 
     /**
      * Disconnects from currently connected host.
+     * The connection state should be tracked by the application by handling callback from
+     * BluetoothHidDeviceCallback#onConnectionStateChanged. The connection state is not related
+     * to the return value of this method.
      *
-     * @return
+     * @return true if the command is successfully sent; otherwise false.
      */
     public boolean disconnect(BluetoothDevice device) {
         Log.v(TAG, "disconnect(): device=" + device);
diff --git a/core/java/android/bluetooth/BluetoothHidDeviceAppQosSettings.java b/core/java/android/bluetooth/BluetoothHidDeviceAppQosSettings.java
index ccc3ef4..881ae98 100644
--- a/core/java/android/bluetooth/BluetoothHidDeviceAppQosSettings.java
+++ b/core/java/android/bluetooth/BluetoothHidDeviceAppQosSettings.java
@@ -45,6 +45,21 @@
 
     public static final int MAX = (int) 0xffffffff;
 
+    /**
+     * Create a BluetoothHidDeviceAppQosSettings object for the Bluetooth L2CAP channel.
+     * The QoS Settings is optional.
+     * Recommended to use BluetoothHidDeviceAppQosSettings.Builder.
+     * {@see <a href="https://www.bluetooth.com/specifications/profiles-overview">
+     *     https://www.bluetooth.com/specifications/profiles-overview
+     *     </a>
+     *     Bluetooth HID Specfication v1.1.1 Section 5.2 and Appendix D }
+     * @param serviceType L2CAP service type
+     * @param tokenRate L2CAP token rate
+     * @param tokenBucketSize L2CAP token bucket size
+     * @param peakBandwidth L2CAP peak bandwidth
+     * @param latency L2CAP latency
+     * @param delayVariation L2CAP delay variation
+     */
     public BluetoothHidDeviceAppQosSettings(int serviceType, int tokenRate, int tokenBucketSize,
             int peakBandwidth, int latency, int delayVariation) {
         this.serviceType = serviceType;
@@ -59,7 +74,12 @@
     public boolean equals(Object o) {
         if (o instanceof BluetoothHidDeviceAppQosSettings) {
             BluetoothHidDeviceAppQosSettings qos = (BluetoothHidDeviceAppQosSettings) o;
-            return false;
+            return this.serviceType == qos.serviceType
+                    && this.tokenRate == qos.tokenRate
+                    && this.tokenBucketSize == qos.tokenBucketSize
+                    && this.peakBandwidth == qos.peakBandwidth
+                    && this.latency == qos.latency
+                    && this.delayVariation == qos.delayVariation;
         }
         return false;
     }
@@ -106,4 +126,85 @@
                 serviceType, tokenRate, tokenBucketSize, peakBandwidth, latency, delayVariation
         };
     }
+
+    /**
+     * A helper to build the BluetoothHidDeviceAppQosSettings object.
+     */
+    public static class Builder {
+        // Optional parameters - initialized to default values
+        private int mServiceType = SERVICE_BEST_EFFORT;
+        private int mTokenRate = 0;
+        private int mTokenBucketSize = 0;
+        private int mPeakBandwidth = 0;
+        private int mLatency = MAX;
+        private int mDelayVariation = MAX;
+
+        /**
+         * Set the service type.
+         * @param val service type. Should be one of {SERVICE_NO_TRAFFIC, SERVICE_BEST_EFFORT,
+         * SERVICE_GUARANTEED}, with SERVICE_BEST_EFFORT being the default one.
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified service type.
+         */
+        public Builder serviceType(int val) {
+            mServiceType = val;
+            return this;
+        }
+        /**
+         * Set the token rate.
+         * @param val token rate
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified token rate.
+         */
+        public Builder tokenRate(int val) {
+            mTokenRate = val;
+            return this;
+        }
+
+        /**
+         * Set the bucket size.
+         * @param val bucket size
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified bucket size.
+         */
+        public Builder tokenBucketSize(int val) {
+            mTokenBucketSize = val;
+            return this;
+        }
+
+        /**
+         * Set the peak bandwidth.
+         * @param val peak bandwidth
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified peak bandwidth.
+         */
+        public Builder peakBandwidth(int val) {
+            mPeakBandwidth = val;
+            return this;
+        }
+        /**
+         * Set the latency.
+         * @param val latency
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified latency.
+         */
+        public Builder latency(int val) {
+            mLatency = val;
+            return this;
+        }
+
+        /**
+         * Set the delay variation.
+         * @param val delay variation
+         * @return BluetoothHidDeviceAppQosSettings Builder with specified delay variation.
+         */
+        public Builder delayVariation(int val) {
+            mDelayVariation = val;
+            return this;
+        }
+
+        /**
+         * Build the BluetoothHidDeviceAppQosSettings object.
+         * @return BluetoothHidDeviceAppQosSettings object with current settings.
+         */
+        public BluetoothHidDeviceAppQosSettings build() {
+            return new BluetoothHidDeviceAppQosSettings(mServiceType, mTokenRate, mTokenBucketSize,
+                    mPeakBandwidth, mLatency, mDelayVariation);
+        }
+    }
 }
diff --git a/core/java/android/bluetooth/BluetoothHidDeviceAppSdpSettings.java b/core/java/android/bluetooth/BluetoothHidDeviceAppSdpSettings.java
index f01c493..4669637 100644
--- a/core/java/android/bluetooth/BluetoothHidDeviceAppSdpSettings.java
+++ b/core/java/android/bluetooth/BluetoothHidDeviceAppSdpSettings.java
@@ -19,6 +19,8 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import java.util.Arrays;
+
 /**
  * Represents the Service Discovery Protocol (SDP) settings for a Bluetooth
  * HID Device application.
@@ -39,6 +41,18 @@
     public final byte subclass;
     public final byte[] descriptors;
 
+    /**
+     * Create a BluetoothHidDeviceAppSdpSettings object for the Bluetooth SDP record.
+     * @param name Name of this Bluetooth HID device. Maximum length is 50 bytes.
+     * @param description Description for this Bluetooth HID device. Maximum length is 50 bytes.
+     * @param provider Provider of this Bluetooth HID device. Maximum length is 50 bytes.
+     * @param subclass Subclass of this Bluetooth HID device.
+     * See <a href="www.usb.org/developers/hidpage/HID1_11.pdf">
+     *     www.usb.org/developers/hidpage/HID1_11.pdf Section 4.2</a>
+     * @param descriptors Descriptors of this Bluetooth HID device.
+     * See <a href="www.usb.org/developers/hidpage/HID1_11.pdf">
+     *     www.usb.org/developers/hidpage/HID1_11.pdf Chapter 6</a> Maximum length is 2048 bytes.
+     */
     public BluetoothHidDeviceAppSdpSettings(String name, String description, String provider,
             byte subclass, byte[] descriptors) {
         this.name = name;
@@ -52,7 +66,11 @@
     public boolean equals(Object o) {
         if (o instanceof BluetoothHidDeviceAppSdpSettings) {
             BluetoothHidDeviceAppSdpSettings sdp = (BluetoothHidDeviceAppSdpSettings) o;
-            return false;
+            return this.name.equals(sdp.name)
+                    && this.description.equals(sdp.description)
+                    && this.provider.equals(sdp.provider)
+                    && this.subclass == sdp.subclass
+                    && Arrays.equals(this.descriptors, sdp.descriptors);
         }
         return false;
     }