https://source.android.com/ 
/*
 * Copyright (C) 2011 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.hardware.usb;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.os.Parcel;
import android.os.Parcelable;
import com.android.internal.util.Preconditions;


A class representing a USB accessory, which is an external hardware component
that communicates with an android application over USB.
The accessory is the USB host and android the device side of the USB connection.

When the accessory connects, it reports its manufacturer and model names,
the version of the accessory, and a user visible description of the accessory to the device.
The manufacturer, model and version strings are used by the USB Manager to choose
an appropriate application for the accessory.
The accessory may optionally provide a unique serial number
and a URL to for the accessory's website to the device as well.

An instance of this class is sent to the application via the UsbManager.ACTION_USB_ACCESSORY_ATTACHED Intent. The application can then call UsbManager.openAccessory to open a file descriptor for reading and writing data to and from the accessory. 


Developer Guides


For more information about communicating with USB hardware, read the
USB developer guide.




/**
 * A class representing a USB accessory, which is an external hardware component
 * that communicates with an android application over USB.
 * The accessory is the USB host and android the device side of the USB connection.
 *
 * <p>When the accessory connects, it reports its manufacturer and model names,
 * the version of the accessory, and a user visible description of the accessory to the device.
 * The manufacturer, model and version strings are used by the USB Manager to choose
 * an appropriate application for the accessory.
 * The accessory may optionally provide a unique serial number
 * and a URL to for the accessory's website to the device as well.
 *
 * <p>An instance of this class is sent to the application via the
 * {@link UsbManager#ACTION_USB_ACCESSORY_ATTACHED} Intent.
 * The application can then call {@link UsbManager#openAccessory} to open a file descriptor
 * for reading and writing data to and from the accessory.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For more information about communicating with USB hardware, read the
 * <a href="{@docRoot}guide/topics/usb/index.html">USB</a> developer guide.</p>
 * </div>
 */
public class UsbAccessory implements Parcelable {

    private static final String TAG = "UsbAccessory";

    private final @NonNull String mManufacturer;
    private final @NonNull String mModel;
    private final @Nullable String mDescription;
    private final @Nullable String mVersion;
    private final @Nullable String mUri;
    private final @Nullable String mSerial;

    
@hide
/** @hide */
    public static final int MANUFACTURER_STRING = 0;
    
@hide
/** @hide */
    public static final int MODEL_STRING = 1;
    
@hide
/** @hide */
    public static final int DESCRIPTION_STRING = 2;
    
@hide
/** @hide */
    public static final int VERSION_STRING = 3;
    
@hide
/** @hide */
    public static final int URI_STRING = 4;
    
@hide
/** @hide */
    public static final int SERIAL_STRING = 5;

    
UsbAccessory should only be instantiated by UsbService implementation

@hide
/**
     * UsbAccessory should only be instantiated by UsbService implementation
     * @hide
     */
    public UsbAccessory(@NonNull String manufacturer, @NonNull String model,
            @Nullable String description, @Nullable String version, @Nullable String uri,
            @Nullable String serial) {
        mManufacturer = Preconditions.checkNotNull(manufacturer);
        mModel = Preconditions.checkNotNull(model);
        mDescription = description;
        mVersion = version;
        mUri = uri;
        mSerial = serial;
    }

    
UsbAccessory should only be instantiated by UsbService implementation

@hide
/**
     * UsbAccessory should only be instantiated by UsbService implementation
     * @hide
     */
    public UsbAccessory(String[] strings) {
        this(strings[MANUFACTURER_STRING], strings[MODEL_STRING], strings[DESCRIPTION_STRING],
                strings[VERSION_STRING], strings[URI_STRING], strings[SERIAL_STRING]);
    }

    
Returns the manufacturer name of the accessory.

Returns:the accessory manufacturer
/**
     * Returns the manufacturer name of the accessory.
     *
     * @return the accessory manufacturer
     */
    public @NonNull String getManufacturer() {
        return mManufacturer;
    }

    
Returns the model name of the accessory.

Returns:the accessory model
/**
     * Returns the model name of the accessory.
     *
     * @return the accessory model
     */
    public @NonNull String getModel() {
        return mModel;
    }

    
Returns a user visible description of the accessory.

Returns:the accessory description, or null if not set
/**
     * Returns a user visible description of the accessory.
     *
     * @return the accessory description, or {@code null} if not set
     */
    public @Nullable String getDescription() {
        return mDescription;
    }

    
Returns the version of the accessory.

Returns:the accessory version, or null if not set
/**
     * Returns the version of the accessory.
     *
     * @return the accessory version, or {@code null} if not set
     */
    public @Nullable String getVersion() {
        return mVersion;
    }

    
Returns the URI for the accessory.
This is an optional URI that might show information about the accessory
or provide the option to download an application for the accessory

Returns:the accessory URI, or null if not set
/**
     * Returns the URI for the accessory.
     * This is an optional URI that might show information about the accessory
     * or provide the option to download an application for the accessory
     *
     * @return the accessory URI, or {@code null} if not set
     */
    public @Nullable String getUri() {
        return mUri;
    }

    
Returns the unique serial number for the accessory.
This is an optional serial number that can be used to differentiate
between individual accessories of the same model and manufacturer

Returns:the unique serial number, or null if not set
/**
     * Returns the unique serial number for the accessory.
     * This is an optional serial number that can be used to differentiate
     * between individual accessories of the same model and manufacturer
     *
     * @return the unique serial number, or {@code null} if not set
     */
    public @Nullable String getSerial() {
        return mSerial;
    }

    private static boolean compare(String s1, String s2) {
        if (s1 == null) return (s2 == null);
        return s1.equals(s2);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof UsbAccessory) {
            UsbAccessory accessory = (UsbAccessory)obj;
            return (compare(mManufacturer, accessory.getManufacturer()) &&
                    compare(mModel, accessory.getModel()) &&
                    compare(mDescription, accessory.getDescription()) &&
                    compare(mVersion, accessory.getVersion()) &&
                    compare(mUri, accessory.getUri()) &&
                    compare(mSerial, accessory.getSerial()));
        }
        return false;
    }

    @Override
    public int hashCode() {
        return mManufacturer.hashCode() ^ mModel.hashCode() ^
                (mDescription == null ? 0 : mDescription.hashCode()) ^
                (mVersion == null ? 0 : mVersion.hashCode()) ^
                (mUri == null ? 0 : mUri.hashCode()) ^ (mSerial == null ? 0 : mSerial.hashCode());
    }

    @Override
    public String toString() {
        return "UsbAccessory[mManufacturer=" + mManufacturer +
                            ", mModel=" + mModel +
                            ", mDescription=" + mDescription +
                            ", mVersion=" + mVersion +
                            ", mUri=" + mUri +
                            ", mSerial=" + mSerial + "]";
    }

    public static final Parcelable.Creator<UsbAccessory> CREATOR =
        new Parcelable.Creator<UsbAccessory>() {
        public UsbAccessory createFromParcel(Parcel in) {
            String manufacturer = in.readString();
            String model = in.readString();
            String description = in.readString();
            String version = in.readString();
            String uri = in.readString();
            String serial = in.readString();
            return new UsbAccessory(manufacturer, model, description, version, uri, serial);
        }

        public UsbAccessory[] newArray(int size) {
            return new UsbAccessory[size];
        }
    };

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel parcel, int flags) {
        parcel.writeString(mManufacturer);
        parcel.writeString(mModel);
        parcel.writeString(mDescription);
        parcel.writeString(mVersion);
        parcel.writeString(mUri);
        parcel.writeString(mSerial);
   }
}