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 eagle.log.entity.meta; import eagle.log.base.taggedlog.TaggedLogAPIEntity; import org.apache.commons.beanutils.PropertyUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.beans.PropertyDescriptor; import java.util.HashMap; import java.util.Map; public class EntitySerDeserializer { private static final Logger LOG = LoggerFactory.getLogger(EntitySerDeserializer.class); // TODO throws seperate exceptions @SuppressWarnings("unchecked") public <T> T readValue(Map<String, byte[]> qualifierValues, EntityDefinition ed) throws Exception { Class<? extends TaggedLogAPIEntity> clazz = ed.getEntityClass(); if (clazz == null) { throw new NullPointerException("Entity class of service " + ed.getService() + " is null"); } TaggedLogAPIEntity obj = clazz.newInstance(); Map<String, Qualifier> map = ed.getQualifierNameMap(); for (Map.Entry<String, byte[]> entry : qualifierValues.entrySet()) { Qualifier q = map.get(entry.getKey()); if (q == null) { // if it's not pre-defined qualifier, it must be tag unless it's a bug if (obj.getTags() == null) { obj.setTags(new HashMap<String, String>()); } obj.getTags().put(entry.getKey(), new StringSerDeser().deserialize(entry.getValue())); continue; } // TODO performance loss compared with new operator // parse different types of qualifiers String fieldName = q.getDisplayName(); PropertyDescriptor pd = PropertyUtils.getPropertyDescriptor(obj, fieldName); if (entry.getValue() != null) { Object args = q.getSerDeser().deserialize(entry.getValue()); pd.getWriteMethod().invoke(obj, args); // if (logger.isDebugEnabled()) { // logger.debug(entry.getKey() + ":" + args + " is deserialized"); // } } } return (T) obj; } public Map<String, byte[]> writeValue(TaggedLogAPIEntity entity, EntityDefinition ed) throws Exception { Map<String, byte[]> qualifierValues = new HashMap<String, byte[]>(); // iterate all modified qualifiers for (String fieldName : entity.modifiedQualifiers()) { PropertyDescriptor pd = PropertyUtils.getPropertyDescriptor(entity, fieldName); Object obj = pd.getReadMethod().invoke(entity); Qualifier q = ed.getDisplayNameMap().get(fieldName); EntitySerDeser<Object> ser = q.getSerDeser(); byte[] value = ser.serialize(obj); qualifierValues.put(q.getQualifierName(), value); } return qualifierValues; } }