Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.usergrid.persistence.model.util; import java.util.ArrayList; import java.util.List; import java.util.Collection; import java.util.UUID; import org.apache.usergrid.persistence.model.field.Field; import org.apache.commons.lang3.reflect.FieldUtils; import org.apache.usergrid.persistence.model.entity.Entity; import org.apache.usergrid.persistence.model.entity.Id; /** * @author tnine */ public class EntityUtils { private static final java.lang.reflect.Field VERSION = FieldUtils.getField(Entity.class, "version", true); private static final java.lang.reflect.Field ID = FieldUtils.getField(Entity.class, "id", true); /** * Set the version into the entity */ public static void setVersion(Entity entity, UUID version) { try { FieldUtils.writeField(VERSION, entity, version, true); } catch (IllegalAccessException e) { throw new RuntimeException("Unable to set the field " + VERSION + " into the entity", e); } } /** * Set the id into the entity */ public static void setId(Entity entity, Id id) { try { FieldUtils.writeField(ID, entity, id, true); } catch (IllegalAccessException e) { throw new RuntimeException("Unable to set the field " + ID + " into the entity", e); } } /** * Get all unique fields on an entity * @param entity * @return */ public static List<Field> getUniqueFields(Entity entity) { final Collection<Field> entityFields = entity.getFields(); //preallocate to max possible for more efficient runtime final List<Field> possibleFields = new ArrayList<>(entityFields.size()); for (Field field : entity.getFields()) { if (field.isUnique()) { possibleFields.add(field); } } return possibleFields; } }