com.sun.jna.NativeMappedConverter Maven / Gradle / Ivy
/* Copyright (c) 2007 Timothy Wall, All Rights Reserved
*
* The contents of this file is dual-licensed under 2
* alternative Open Source/Free licenses: LGPL 2.1 or later and
* Apache License 2.0. (starting with JNA version 4.0.0).
*
* You can freely decide which license you want to apply to
* the project.
*
* You may obtain a copy of the LGPL License at:
*
* http://www.gnu.org/licenses/licenses.html
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "LGPL2.1".
*
* You may obtain a copy of the Apache License at:
*
* http://www.apache.org/licenses/
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "AL2.0".
*/
package com.sun.jna;
import java.lang.ref.Reference;
import java.lang.ref.SoftReference;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.WeakHashMap;
/** Provides type conversion for instances of {@link NativeMapped}. */
public class NativeMappedConverter implements TypeConverter {
private static final Map, Reference> converters =
new WeakHashMap, Reference>();
private final Class type;
private final Class nativeType;
private final NativeMapped instance;
public static NativeMappedConverter getInstance(Class cls) {
synchronized(converters) {
Reference r = converters.get(cls);
NativeMappedConverter nmc = r != null ? r.get() : null;
if (nmc == null) {
nmc = new NativeMappedConverter(cls);
converters.put(cls, new SoftReference(nmc));
}
return nmc;
}
}
public NativeMappedConverter(Class type) {
if (!NativeMapped.class.isAssignableFrom(type))
throw new IllegalArgumentException("Type must derive from " + NativeMapped.class);
this.type = type;
this.instance = defaultValue();
this.nativeType = instance.nativeType();
}
public NativeMapped defaultValue() {
if (type.isEnum()) {
return (NativeMapped) type.getEnumConstants()[0];
}
return (NativeMapped) Klass.newInstance(type);
}
@Override
public Object fromNative(Object nativeValue, FromNativeContext context) {
return instance.fromNative(nativeValue, context);
}
@Override
public Class nativeType() {
return nativeType;
}
@Override
public Object toNative(Object value, ToNativeContext context) {
if (value == null) {
if (Pointer.class.isAssignableFrom(nativeType)) {
return null;
}
value = defaultValue();
}
return ((NativeMapped)value).toNative();
}
}