src/main/java/org/onap/dmaap/dbcapi/aaf/database/DBSingleton.java

   1 /*-
   2  * ============LICENSE_START=======================================================
   3  * org.onap.dmaap
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
   6  * ================================================================================
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  * ============LICENSE_END=========================================================
  19  */
  20
  21 package org.onap.dmaap.dbcapi.aaf.database;
  22
  23 import java.sql.*;
  24 import java.util.*;
  25
  26 import org.onap.dmaap.dbcapi.util.Singleton;
  27
  28 public class DBSingleton<C> extends TableHandler<C> implements Singleton<C>     {
  29         private C singleton;
  30         public DBSingleton(Class<C> cls, String tabname) throws Exception {
  31                 this(ConnectionFactory.getDefaultInstance(), cls, tabname);
  32         }
  33         public DBSingleton(ConnectionFactory cf, Class<C> cls, String tabname) throws Exception {
  34                 super(cf, cls, tabname, null);
  35                 singleton = cls.newInstance();
  36         }
  37         public C get() throws DBException {
  38                 return((new ConnWrapper<C, Object>() {
  39                         protected C run(Object junk) throws Exception {
  40                                 ps = c.prepareStatement(getstmt);
  41                                 rs = ps.executeQuery();
  42                                 if (!rs.next()) {
  43                                         return(null);
  44                                 }
  45                                 for (DBFieldHandler f: fields) {
  46                                         f.fromSQL(rs, singleton);
  47                                 }
  48                                 return(singleton);
  49                         }
  50                 }).protect(cf, null));
  51         }
  52         public void init(C val) throws DBException {
  53                 if (get() != null) {
  54                         return;
  55                 }
  56                 (new ConnWrapper<Void, C>() {
  57                         protected Void run(C val) throws Exception {
  58                                 ps = c.prepareStatement(initstmt);
  59                                 for (DBFieldHandler f: fields) {
  60                                         f.toSQL(val, ps);
  61                                 }
  62                                 ps.executeUpdate();
  63                                 if (val != singleton) {
  64                                         for (DBFieldHandler f: fields) {
  65                                                 f.copy(val, singleton);
  66                                         }
  67                                 }
  68                                 return(null);
  69                         }
  70                 }).protect(cf, val);
  71         }
  72         public void update(C val) throws DBException {
  73                 (new ConnWrapper<Void, C>() {
  74                         protected Void run(C val) throws Exception {
  75                                 ps = c.prepareStatement(insorreplstmt);
  76                                 for (DBFieldHandler f: fields) {
  77                                         f.toSQL(val, ps);
  78                                 }
  79                                 ps.executeUpdate();
  80                                 if (val != singleton) {
  81                                         for (DBFieldHandler f: fields) {
  82                                                 f.copy(val, singleton);
  83                                         }
  84                                 }
  85                                 return(null);
  86                         }
  87                 }).protect(cf, val);
  88         }
  89         public void remove() throws DBException {
  90                 (new ConnWrapper<Void, Object>() {
  91                         protected Void run(Object junk) throws Exception {
  92                                 ps = c.prepareStatement(delstmt);
  93                                 ps.executeUpdate();
  94                                 return(null);
  95                         }
  96                 }).protect(cf, null);
  97         }
  98 }