Base class for item driver providers.

src/main/java/li/cil/oc2/common/bus/device/provider/util/AbstractItemDeviceProvider.java

@@ -0,0 +1,38 @@
+package li.cil.oc2.common.bus.device.provider.util;
+
+import li.cil.oc2.api.bus.device.Device;
+import li.cil.oc2.api.bus.device.provider.DeviceProvider;
+import li.cil.oc2.api.bus.device.provider.DeviceQuery;
+import li.cil.oc2.api.bus.device.provider.ItemDeviceQuery;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+import net.minecraftforge.common.util.LazyOptional;
+
+public abstract class AbstractItemDeviceProvider implements DeviceProvider {
+    private final Item item;
+
+    protected AbstractItemDeviceProvider(final Item item) {
+        this.item = item;
+    }
+
+    @Override
+    public LazyOptional<Device> getDevice(final DeviceQuery query) {
+        if (!(query instanceof ItemDeviceQuery)) {
+            return LazyOptional.empty();
+        }
+
+        final ItemDeviceQuery itemDeviceQuery = (ItemDeviceQuery) query;
+        final ItemStack stack = itemDeviceQuery.getItemStack();
+        if (stack.isEmpty()) {
+            return LazyOptional.empty();
+        }
+
+        if (stack.getItem() != item) {
+            return LazyOptional.empty();
+        }
+
+        return getItemDevice(itemDeviceQuery);
+    }
+
+    protected abstract LazyOptional<Device> getItemDevice(final ItemDeviceQuery query);
+}