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package oms3.util;

import com.sun.jna.Library;
import com.sun.jna.Native;
import oms3.annotations.DLL;

/**
 * Simplifies runtime binding of dynamic shared libraries to Java Interfaces.
 * 
 * @author od
 */
public class NativeLibraries {

    private NativeLibraries() {
    }

    /**
     * Maps a DLL to an interface using the @DLL annotation.
     *
     * @param <T> The interface type
     * @param intf  The interface class
     * @return the Library instance of type T
     *
     * @see oms3.annotations.DLL
     */
    public static <T extends Library> T bind(Class<T> intf) {
        DLL dll = intf.getAnnotation(DLL.class);
        if (dll == null) {
            throw new IllegalArgumentException("Missing DLL annotation.");
        }
        return bind(dll.value(), intf);
    }

    /**
     * Bind the Library 'name' to the interface 'intf', No annotation needed.
     * 
     * @param <T>
     * @param name the library name, if not provided the Interface
     *             must be annotated with '@DLL'
     * @param intf the interface
     * @return The library interface bound to a DLL.
     */
    @SuppressWarnings("unchecked")
    public static <T extends Library> T bind(String name, Class<T> intf) {

        if (!intf.isInterface()) {
            throw new IllegalArgumentException("Expected interface, but got '" + intf + "'.");
        }
        if (name.isEmpty()) {
            throw new IllegalArgumentException("Empty library name.");
        }
        Native.setProtected(true);
        return (T) Native.loadLibrary(name, intf);
    }
}