DBTGattDesc.java

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/**
 * Author: Sven Gothel <sgothel@jausoft.com>
 * Copyright (c) 2020 Gothel Software e.K.
 * Copyright (c) 2020 ZAFENA AB
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
package jau.direct_bt;
 
import java.lang.ref.WeakReference;
 
import org.direct_bt.BTException;
import org.direct_bt.BTGattDesc;
 
public class DBTGattDesc extends DBTObject implements BTGattDesc
{
    /** Descriptor's characteristic weak back-reference */
    final WeakReference<DBTGattChar> wbr_characteristic;
 
    /** Type of Descriptor */
    private final String type_uuid;
 
    /**
     * Characteristic Descriptor Handle
     * <p>
     * Attribute handles are unique for each device (server) (BT Core Spec v5.2: Vol 3, Part F Protocol..: 3.2.2 Attribute Handle).
     * </p>
     */
    private final short handle;
 
    private byte[] cachedValue;
 
    private void updateCachedValue(final byte[] value) {
        if( null == cachedValue || cachedValue.length != value.length ) {
            cachedValue = new byte[value.length];
        }
        System.arraycopy(value, 0, cachedValue, 0, value.length);
    }
 
   /* pp */ DBTGattDesc(final long nativeInstance, final DBTGattChar characteristic,
                              final String type_uuid, final short handle, final byte[] value)
    {
        super(nativeInstance, handle /* hash */);
        this.wbr_characteristic = new WeakReference<DBTGattChar>(characteristic);
        this.type_uuid = type_uuid;
        this.handle = handle;
        this.cachedValue = value;
    }
 
    @Override
    public synchronized void close() {
        if( !isNativeValid() ) {
            return;
        }
        super.close();
    }
 
    @Override
    public boolean equals(final Object obj)
    {
        if (obj == null || !(obj instanceof DBTGattDesc)) {
            return false;
        }
        final DBTGattDesc other = (DBTGattDesc)obj;
        return handle == other.handle; /** unique attribute handles */
    }
 
    @Override
    public String getUUID() { return type_uuid; }
 
    @Override
    public final DBTGattChar getCharacteristic() { return wbr_characteristic.get(); }
 
    @Override
    public final byte[] getValue() { return cachedValue; }
 
    @Override
    public final byte[] readValue() {
        final byte[] value = readValueImpl();
        updateCachedValue(value);
        return cachedValue;
    }
 
    @Override
    public final boolean writeValue(final byte[] value) throws BTException {
        final boolean res = writeValueImpl(value);
        if( res ) {
            updateCachedValue(value);
        }
        return res;
    }
 
    /**
     * Characteristic Descriptor Handle
     * <p>
     * Attribute handles are unique for each device (server) (BT Core Spec v5.2: Vol 3, Part F Protocol..: 3.2.2 Attribute Handle).
     * </p>
     */
    public final short getHandle() { return handle; }
 
    @Override
    public final String toString() {
        if( !isNativeValid() ) {
            return "Descriptor" + "\u271D" + "[uuid "+getUUID()+", handle 0x"+Integer.toHexString(handle)+"]";
        }
        return toStringImpl();
    }
 
    /* Native method calls: */
 
    private native String toStringImpl();
 
    private native byte[] readValueImpl();
 
    private native boolean writeValueImpl(byte[] argValue) throws BTException;
 
    @Override
    protected native void deleteImpl(long nativeInstance);
}