create TypeToken

common/api/src/main/java/com/dfsek/terra/api/util/ReflectionUtil.java

@@ -4,8 +4,14 @@ import org.jetbrains.annotations.NotNull;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Array;
 import java.lang.reflect.Field;
+import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.Method;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
+import java.lang.reflect.WildcardType;
 import java.util.Arrays;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
@@ -33,4 +39,29 @@ public final class ReflectionUtil {
         T a = element.getAnnotation(annotation);
         if(a != null) operation.accept(a);
     }
+
+    public static Class<?> getRawType(Type type) {
+        if (type instanceof Class<?>) {
+            return (Class<?>) type;
+        } else if (type instanceof ParameterizedType) {
+            ParameterizedType parameterizedType = (ParameterizedType) type;
+            Type rawType = parameterizedType.getRawType();
+            return (Class<?>) rawType;
+        } else if (type instanceof GenericArrayType) {
+            Type componentType = ((GenericArrayType)type).getGenericComponentType();
+            return Array.newInstance(getRawType(componentType), 0).getClass();
+        } else if (type instanceof TypeVariable) {
+            return Object.class;
+        } else if (type instanceof WildcardType) {
+            return getRawType(((WildcardType) type).getUpperBounds()[0]);
+        } else {
+            String className = type == null ? "null" : type.getClass().getName();
+            throw new IllegalArgumentException("Expected a Class, ParameterizedType, or "
+                    + "GenericArrayType, but <" + type + "> is of type " + className);
+        }
+    }
+
+    public static String typeToString(Type type) {
+        return type instanceof Class ? ((Class<?>) type).getName() : type.toString();
+    }
 }

common/api/src/main/java/com/dfsek/terra/api/util/TypeToken.java

@@ -0,0 +1,104 @@
+package com.dfsek.terra.api.util;
+
+import java.lang.reflect.*;
+import java.util.Arrays;
+import java.util.Objects;
+
+public class TypeToken<T> {
+    final Class<? super T> rawType;
+    final Type type;
+    final int hashCode;
+
+    @SuppressWarnings("unchecked")
+    protected TypeToken() {
+        this.type = getSuperclassTypeParameter(getClass());
+        this.rawType = (Class<? super T>) ReflectionUtil.getRawType(type);
+        this.hashCode = type.hashCode();
+    }
+
+
+    static Type getSuperclassTypeParameter(Class<?> subclass) {
+        Type superclass = subclass.getGenericSuperclass();
+        if(superclass instanceof Class) {
+            throw new RuntimeException("Missing type parameter.");
+        }
+        ParameterizedType parameterized = (ParameterizedType) superclass;
+        return parameterized.getActualTypeArguments()[0];
+    }
+
+    /**
+     * Returns the raw (non-generic) type for this type.
+     */
+    public final Class<? super T> getRawType() {
+        return rawType;
+    }
+
+    /**
+     * Gets underlying {@code Type} instance.
+     */
+    public final Type getType() {
+        return type;
+    }
+
+    @Override
+    public final int hashCode() {
+        return this.hashCode;
+    }
+
+    @Override
+    public final boolean equals(Object o) {
+        return o instanceof TypeToken<?>
+                && equals(type, ((TypeToken<?>) o).type);
+    }
+
+    @Override
+    public final String toString() {
+        return ReflectionUtil.typeToString(type);
+    }
+
+    public static boolean equals(Type a, Type b) {
+        if(a == b) {
+            return true;
+        } else if(a instanceof Class) {
+            return a.equals(b);
+        } else if(a instanceof ParameterizedType) {
+            if(!(b instanceof ParameterizedType)) {
+                return false;
+            }
+
+            ParameterizedType pa = (ParameterizedType) a;
+            ParameterizedType pb = (ParameterizedType) b;
+            return Objects.equals(pa.getOwnerType(), pb.getOwnerType())
+                    && pa.getRawType().equals(pb.getRawType())
+                    && Arrays.equals(pa.getActualTypeArguments(), pb.getActualTypeArguments());
+        } else if(a instanceof GenericArrayType) {
+            if(!(b instanceof GenericArrayType)) {
+                return false;
+            }
+
+            GenericArrayType ga = (GenericArrayType) a;
+            GenericArrayType gb = (GenericArrayType) b;
+            return equals(ga.getGenericComponentType(), gb.getGenericComponentType());
+        } else if(a instanceof WildcardType) {
+            if(!(b instanceof WildcardType)) {
+                return false;
+            }
+
+            WildcardType wa = (WildcardType) a;
+            WildcardType wb = (WildcardType) b;
+            return Arrays.equals(wa.getUpperBounds(), wb.getUpperBounds())
+                    && Arrays.equals(wa.getLowerBounds(), wb.getLowerBounds());
+        } else if(a instanceof TypeVariable) {
+            if(!(b instanceof TypeVariable)) {
+                return false;
+            }
+            TypeVariable<?> va = (TypeVariable<?>) a;
+            TypeVariable<?> vb = (TypeVariable<?>) b;
+            return va.getGenericDeclaration() == vb.getGenericDeclaration()
+                    && va.getName().equals(vb.getName());
+        } else {
+            return false;
+        }
+    }
+}
+