目 次

目
次
はじめに
第 1 章 EJB コンポーネントとは············································································ 15
1.1
これまでの C/S システムと分散オブジェクト ·············································· 16
1.1.1
クライアント/サーバと分散オブジェクト······················································ 16
1.1.2
分散オブジェクト ······························································································ 18
1.1.3
CORBA による分散オブジェクト ··································································· 20
1.1.4
Java 標準の分散オブジェクト−Java-RMI ·················································· 22
1.1.5
Java ローカルコンポーネント−JavaBeans ················································· 24
1.2
EJB 仕様の目的と概要 ····················································································· 27
1.2.1
EJB が目指すもの ····························································································· 27
1.2.2
ネットワーク/分散の隠蔽 ················································································· 28
1.2.3
インスタンス管理の分離 ·················································································· 29
1.2.4
永続性の分離 ······································································································ 30
(1)
JDBC アクセス ·································································································· 30
(2)
トランザクション制御との連携 ······································································ 30
(3)
エンティティとインスタンスの分離······························································· 31
1.2.5
トランザクション管理の分離 ·········································································· 31
(1)
JTS(Java Transaction Service)······································································ 32
(2)
JTA(Java Transaction API) ··········································································· 32
(3)
リソースマネージャ ·························································································· 33
7
第 2 章 EJB アーキテクチャ ····················································································· 35
2.1
EJB の全体像 ····································································································· 36
2.2
6 つのロールとシナリオ ··················································································· 38
(1)
エンタプライズ Bean プロバイダ ··································································· 39
(2)
アプリケーションアセンブラ ·········································································· 39
(3)
デプロイヤ ·········································································································· 39
(4)
EJB サーバプロバイダ ····················································································· 40
(5)
EJB コンテナプロバイダ ················································································· 40
(6)
システム管理者 ·································································································· 40
(7)
シナリオ ·············································································································· 41
2.3
EJB アクセスモデル ························································································· 42
(1)
EJBHome オブジェクトと home インタフェース ······································· 42
(2)
EJBObject と remote インタフェース ··························································· 43
(3)
エンタプライズ Bean 開発の 3 つの基本セット ··········································· 43
2.4
EJB サーバ(EJB コンテナとネーミングサービス) ······································ 44
(1)
EJB コンテナ ····································································································· 44
(2)
ネーミングサービス ·························································································· 44
2.5
EJBHome と home インタフェース······························································· 45
2.6
EJBObject と remote インタフェース ··························································· 46
2.7
Bean の種類 ······································································································· 47
2.8
Bean インスタンスの一生 ················································································ 48
(1)
エンタプライズ Bean の識別 ··········································································· 49
(2)
remove メソッド ······························································································· 50
2.9
セッション Bean ······························································································· 50
2.9.1
ステートレスセッション Bean ········································································ 52
2.9.2
ステートフルセッション Bean ········································································ 53
2.9.3
ステートフルセッション Bean の非活性化 ··················································· 54
2.10
エンティティ Bean ··························································································· 55
2.10.1 主キークラス ······································································································ 57
2.10.2 BMP エンティティ Bean ················································································· 58
2.10.3 CMP エンティティ Bean ················································································· 59
8
2.10.4 エンティティ Bean の home インタフェース ··············································· 60
2.10.5 エンティティ Bean の home インタフェースの例外 ··································· 63
2.10.6 エンティティ Bean の永続化コード ······························································· 64
2.11
トランザクション管理 ······················································································ 66
2.11.1 Bean 管理によるトランザクション区切り ···················································· 66
2.11.2 コンテナ管理によるトランザクション区切り ··············································· 67
2.11.3 BeanManaged ··································································································· 68
2.11.4 NotSupported ···································································································· 69
2.11.5 Required ············································································································· 70
2.11.6 Supports ············································································································· 72
2.11.7 RequiresNew ····································································································· 73
2.11.8 Mandatory ········································································································· 74
2.11.9 Never ·················································································································· 75
2.11.10 クライアント管理によるトランザクション区切り ······································· 75
2.11.11 分離レベル ·········································································································· 76
2.11.12 SessionSynchronization インタフェース······················································ 78
2.12
セキュリティ ······································································································ 79
(1)
アプリケーションアセンブラが行うこと······················································· 79
(2)
デプロイヤが行うこと ······················································································ 80
(3)
Bean クラスが行うこと···················································································· 80
2.13
エンタプライズ Bean からの例外 ··································································· 81
(1)
アプリケーション例外 ······················································································ 81
(2)
システム例外 ······································································································ 82
(3)
EJB クライアントでの例外処理 ····································································· 82
2.14
デプロイメント記述 ·························································································· 84
2.15
エンタプライズ Bean 環境 ··············································································· 86
(1)
EJBContext.getEnvironment()メソッド ······················································ 87
(2)
JNDI からの取得 ······························································································· 87
2.16
J2EE での位置づけと開発モデル ··································································· 88
2.17
開発手法とデプロイ ·························································································· 89
9
第 3 章 EJB 仕様の変遷 ······························································································ 93
3.1
EJB 誕生前夜から EJB2.0 まで ······································································ 93
3.1.1
アプレット用簡易言語から実用言語への道 ··················································· 93
3.1.2
サーバサイドコンポーネントモデルの誕生 ··················································· 96
3.1.3
Java 2 と EJB1.1 ······························································································ 98
3.1.4
JCP と EJB2.0··································································································· 99
3.2
EJB1.0 から EJB1.1 への移行 ······································································ 104
(1)
デプロイメント記述の変換 ············································································ 104
(2)
コンテナ管理による永続性(CMP)を利用するときの ejbCreate の返却値型
··························································································································· 104
(3)
例外の取り扱い ································································································ 105
(4)
エンタプライズ Bean 環境(EBE)変数の取得 ·············································· 105
(5)
home インタフェースの取得 ········································································· 105
(6)
UserTransaction クラスの違い ···································································· 106
(7)
セッション Bean の transient 変数 ······························································ 106
(8)
主キークラスの hashCode と equals ··························································· 106
3.3
最新 EJB 仕様紹介 ·························································································· 108
3.3.1
ローカルインタフェース ················································································ 108
3.3.2
メッセージドリブン Bean ·············································································· 115
3.3.3
抽象永続スキーマによる CMP ······································································ 122
3.3.4
コンテナ管理によるエンティティ Bean 間関連 ········································· 129
3.3.5
Enterprise JavaBeans Query Language(EJB QL) ·································· 134
(1)
FROM 句 ·········································································································· 136
(2)
WHERE 句 ······································································································· 136
(3)
SELECT 句 ······································································································ 137
3.3.6
home インタフェースの機能拡張 ································································· 138
第 4 章 EJB コンポーネント流通の取り組み ·················································· 141
10
4.1
コンポーネント流通市場(マーケットプレイス)の誕生 ······························ 142
4.2
EJB コンポーネントに関するコンソーシアム ············································ 143
4.2.1
コンソーシアムの活動内容 ············································································ 144
4.3
ポータブルなコンポーネントを作るために ················································· 147
4.3.1
ポータブルコンポーネント規約策定の目的 ················································· 148
4.3.2
ポータブルコンポーネント規約の対象範囲 ················································· 149
4.3.3
ポータビリティの定義 ···················································································· 152
4.3.4
ポータビリティの定義に含まないこと························································· 157
4.3.5
規約···················································································································· 159
(1)
エンタプライズ Bean 全般 ············································································· 159
(1-1) プロセス境界に依存した操作の禁止····························································· 159
(1-2) エンタプライズ Bean 呼び出しに関する規約 ············································· 162
(1-3) セキュリティ管理に関する規約 ···································································· 172
(1-4) 分散処理管理に関する規約 ············································································ 175
(1-5) 入出力に関する規約 ························································································ 175
(1-6) オブジェクト同一性の仮定の禁止 ································································ 177
(1-7) コールバックメソッドでのタイミング依存ロジック実装の禁止 ············· 181
(1-8) 利用コンポーネント/クラスの等価性 ··························································· 182
(1-9) handle の有効性仮定の禁止··········································································· 186
(2)
セッション Bean ····························································································· 186
(2-1) データフィールド使用方法の制約 ································································ 186
(2-2) ejbRemove への依存禁止 ··············································································· 191
(3)
エンティティ Bean ························································································· 192
(3-1) データベースに格納しないデータフィールドに関する処理 ····················· 192
(4)
Bean 管理による永続性(BMP) ······································································ 196
(4-1) 主キーオブジェクトの同一性を前提とした実装の禁止 ····························· 196
(5)
コンテナ管理による永続性(CMP) ································································ 198
(5-1) コンテナ管理による永続性の機能範囲························································· 198
(5-2) 主キーの制限 ···································································································· 199
(6)
トランザクション ···························································································· 200
(6-1) 伝播するトランザクションのロールバック検出の制限 ····························· 200
(7)
エンタプライズ Bean 環境 ············································································· 201
(7-1) エンタプライズ Bean 環境へのアクセス ····················································· 201
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第 5 章 EJB コンポーネント作成技法 ································································ 203
5.1
EJB コンポーネントをデザインする···························································· 204
5.1.1
外部仕様の決定 ································································································ 204
5.1.2
内部仕様の決定 ································································································ 206
5.2
例題：商品コンポーネント ············································································ 208
5.2.1
要求仕様 ············································································································ 208
5.2.2
データ構造 ········································································································ 209
5.2.3
アプリケーションとしてのモデル化····························································· 210
(1)
セッション Bean でラッピングする ····························································· 211
(2)
アクセス用のプロキシクラスを作る····························································· 212
5.3
名前の整理 ········································································································ 213
5.4
例外クラスの定義 ···························································································· 214
5.5
home ヘルパー ································································································· 218
5.6
home インタフェースの定義 ········································································· 222
5.7
remote インタフェースの定義 ······································································ 225
5.8
エンタプライズ Bean クラスの実装 ····························································· 229
5.8.1
主キークラス ···································································································· 229
5.8.2
CMP エンティティ Bean ··············································································· 231
5.8.3
カスタム finder ································································································ 243
5.8.4
BMP エンティティ Bean ··············································································· 244
(1)
setEntityContext，unsetEntityContext ···················································· 244
(2)
ejbCreate，ejbFindXXX，ejbStore，ejbLoad，ejbRemove ··················· 245
5.9
ラッピング用のセッション Bean ·································································· 245
5.9.1
ステートレスセッション Bean ······································································ 245
5.9.2
ステートフルセッション Bean ······································································ 254
5.9.3
トランザクショナルセッション Bean ·························································· 254
5.10
クライアントコードの実装 ············································································ 256
5.11
アクセス用プロキシクラス ············································································ 261
5.12
課題点と改善のアイデア ················································································ 266
5.12.1 home ヘルパーのデザイン ············································································· 266
5.12.2 エンティティ Bean メソッドの粒度 ····························································· 267
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索
引 ································································································································ 269
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