1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 package org.apache.giraph.types.ops; 19 20 21 /** 22 * Type operations, allowing working generically with mutable types, 23 * but still having efficient code. 24 * For example, by reducing object allocation via reuse. 25 * 26 * Use enum singleton pattern, having single enum value - INSTANCE. 27 * Serialization code depends on implementations being enums. 28 * 29 * @param <T> Type 30 */ 31 public interface TypeOps<T> { 32 /** 33 * Class object for generic type T. 34 * @return Class<T> object 35 */ 36 Class<T> getTypeClass(); 37 /** 38 * Create new instance of type T. 39 * @return new instance 40 */ 41 T create(); 42 /** 43 * Create a copy of passed object 44 * @param from Object to copy 45 * @return Copy 46 */ 47 T createCopy(T from); 48 /** 49 * Copies the value from the second argument into the first. 50 * @param to Object into which the value should be copied 51 * @param from Value of object to be copied 52 */ 53 void set(T to, T from); 54 }