Class Native

src/com/sun/jna/Native.java:112–2565

Provides generation of invocation plumbing for a defined native library interface. Also provides various utilities for native operations. #getTypeMapper and #getStructureAlignment are provided to avoid having to explicitly pass these parameters to Structures, which would

 * @author twall@users.sf.net
 */
public final class Native implements Version {

    private static final Logger LOG = Logger.getLogger(Native.class.getName());

    public static final Charset DEFAULT_CHARSET;
    public static final String DEFAULT_ENCODING;
    static {
        // JNA used the defaultCharset to determine which encoding to use when
        // converting strings to native char*. The defaultCharset is set from
        // the system property file.encoding. Up to JDK 17 its value defaulted
        // to the system default encoding. From JDK 18 onwards its default value
        // changed to UTF-8.
        // JDK 18+ exposes the native encoding as the new system property
        // native.encoding, prior versions don't have that property and will
        // report NULL for it.
        // The algorithm is simple: If native.encoding is set, it will be used
        // else the original implementation of Charset#defaultCharset is used
        String nativeEncoding = System.getProperty("native.encoding");
        Charset nativeCharset = null;
        if (nativeEncoding != null) {
            try {
                nativeCharset = Charset.forName(nativeEncoding);
            } catch (Exception ex) {
                LOG.log(Level.WARNING, "Failed to get charset for native.encoding value : '" + nativeEncoding + "'", ex);
            }
        }
        if (nativeCharset == null) {
            nativeCharset = Charset.defaultCharset();
        }
        DEFAULT_CHARSET = nativeCharset;
        DEFAULT_ENCODING = nativeCharset.name();
    }
    public static final boolean DEBUG_LOAD = Boolean.getBoolean("jna.debug_load");
    public static final boolean DEBUG_JNA_LOAD = Boolean.getBoolean("jna.debug_load.jna");
    private final static Level DEBUG_JNA_LOAD_LEVEL = DEBUG_JNA_LOAD ? Level.INFO : Level.FINE;

    // Used by tests, do not remove
    static String jnidispatchPath = null;
    private static final Map<Class<?>, Map<String, Object>> typeOptions = Collections.synchronizedMap(new WeakHashMap<Class<?>, Map<String, Object>>());
    private static final Map<Class<?>, Reference<?>> libraries = Collections.synchronizedMap(new WeakHashMap<Class<?>, Reference<?>>());
    private static final String _OPTION_ENCLOSING_LIBRARY = "enclosing-library";
    private static final UncaughtExceptionHandler DEFAULT_HANDLER =
        new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Callback c, Throwable e) {
                LOG.log(Level.WARNING, "JNA: Callback " + c + " threw the following exception", e);
            }
        };
    private static UncaughtExceptionHandler callbackExceptionHandler = DEFAULT_HANDLER;

    /** The size of a native pointer (<code>void*</code>) on the current
     * platform, in bytes.
     */
    public static final int POINTER_SIZE;
    /** Size of a native <code>long</code> type, in bytes. */
    public static final int LONG_SIZE;
    /** Size of a native <code>wchar_t</code> type, in bytes. */
    public static final int WCHAR_SIZE;