package net.minecraftforge.fml.common.registry; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import org.apache.logging.log4j.Level; import com.google.common.base.Throwables; import net.minecraft.block.Block; import net.minecraft.init.Blocks; import net.minecraft.item.Item; import net.minecraftforge.fml.common.FMLLog; import net.minecraftforge.fml.common.registry.GameRegistry.ObjectHolder; /** * Internal class used in tracking {@link ObjectHolder} references * * @author cpw * */ class ObjectHolderRef { private Field field; private String injectedObject; private boolean isBlock; private boolean isItem; ObjectHolderRef(Field field, String injectedObject, boolean extractFromExistingValues) { this.field = field; this.isBlock = Block.class.isAssignableFrom(field.getType()); this.isItem = Item.class.isAssignableFrom(field.getType()); if (extractFromExistingValues) { try { Object existing = field.get(null); // nothing is ever allowed to replace AIR if (existing == null || existing == GameData.getBlockRegistry().getDefaultValue()) { this.injectedObject = null; this.field = null; this.isBlock = false; this.isItem = false; return; } else { Object tmp = isBlock ? GameData.getBlockRegistry().getNameForObject(existing) : isItem ? GameData.getItemRegistry().getNameForObject(existing) : null; this.injectedObject = tmp != null ? tmp.toString() : null; } } catch (Exception e) { throw Throwables.propagate(e); } } else { this.injectedObject = injectedObject; } if (this.injectedObject == null || !isValid()) { throw new IllegalStateException("The ObjectHolder annotation cannot apply to a field that is not an Item or Block"); } makeWritable(field); } private static Field modifiersField; private static Object reflectionFactory; private static Method newFieldAccessor; private static Method fieldAccessorSet; private static void makeWritable(Field f) { try { if (modifiersField == null) { Method getReflectionFactory = Class.forName("sun.reflect.ReflectionFactory").getDeclaredMethod("getReflectionFactory"); reflectionFactory = getReflectionFactory.invoke(null); newFieldAccessor = Class.forName("sun.reflect.ReflectionFactory").getDeclaredMethod("newFieldAccessor", Field.class, boolean.class); fieldAccessorSet = Class.forName("sun.reflect.FieldAccessor").getDeclaredMethod("set", Object.class, Object.class); modifiersField = Field.class.getDeclaredField("modifiers"); modifiersField.setAccessible(true); } modifiersField.setInt(f, f.getModifiers() & ~Modifier.FINAL); } catch (Exception e) { throw Throwables.propagate(e); } } public boolean isValid() { return isBlock || isItem; } public void apply() { Object thing; if (isBlock) { thing = GameData.getBlockRegistry().getObject(injectedObject); if (thing == Blocks.air) { thing = null; } } else if (isItem) { thing = GameData.getItemRegistry().getObject(injectedObject); } else { thing = null; } if (thing == null) { FMLLog.warning("Unable to lookup %s for %s. Is there something wrong with the registry?", injectedObject, field); return; } try { Object fieldAccessor = newFieldAccessor.invoke(reflectionFactory, field, false); fieldAccessorSet.invoke(fieldAccessor, null, thing); } catch (Exception e) { FMLLog.log(Level.WARN, e, "Unable to set %s with value %s (%s)", this.field, thing, this.injectedObject); } } }