2008年1月15日火曜日

jPersistを試してみる

JavaでActiveRecord、てのが気になったので試してみることにした。サポートされているDBはPDFのリファレンスを見ると次の通りだそぅだ。
Supported Databases Right now our focus is on adding support for as many databases as we can, and jPersist currently has complete, and fully tested, support for:
  • MySqlDB2
  • Oracle
  • Derby
  • HSQL
  • PostgreSQL
  • H2
HSQLDBを使う前提での作業。
  • hsqldb/sample.properties 
    #HSQL Database Engine 1.8.0.7
#Wed Jan 16 03:33:41 GMT+09:00 2008
hsqldb.script_format=0
runtime.gc_interval=0
sql.enforce_strict_size=false
hsqldb.cache_size_scale=8
readonly=false
hsqldb.nio_data_file=true
hsqldb.cache_scale=14
version=1.8.0
hsqldb.default_table_type=memory
hsqldb.cache_file_scale=1
hsqldb.log_size=200
modified=no
hsqldb.cache_version=1.7.0
hsqldb.original_version=1.8.0
hsqldb.compatible_version=1.8.0
  • hsqldb/sample.script 
    CREATE SCHEMA PUBLIC AUTHORIZATION DBA
CREATE MEMORY TABLE DEPARTMENTS(DEPARTMENT_ID INTEGER GENERATED BY DEFAULT AS IDENTITY(START WITH 0) NOT NULL PRIMARY KEY,NAME VARCHAR(100))
CREATE MEMORY TABLE MEMBERS(MEMBER_ID INTEGER GENERATED BY DEFAULT AS IDENTITY(START WITH 0) NOT NULL PRIMARY KEY,DEPARTMENT_ID INTEGER NOT NULL,NAME VARCHAR(100),CONSTRAINT MEMERS_FKEY_01 FOREIGN KEY(DEPARTMENT_ID) REFERENCES DEPARTMENTS(DEPARTMENT_ID) ON DELETE CASCADE ON UPDATE CASCADE)
CREATE USER SA PASSWORD ""
GRANT DBA TO SA
SET WRITE_DELAY 10
SET SCHEMA PUBLIC
    非常に横に長いが、整形するとHSQLDBが解析に失敗するのでこのままの状態で。
  • src/main/resources/databases.xml 
    <databases>
  <database name="studyJPersist_hsqldb" poolSize="10"
    driver="org.hsqldb.jdbcDriver" url="jdbc:hsqldb:file:hsqldb/sample" />
</databases>
    class出力フォルダの直下にあれば良い。eclipseならsrc/databases.xmlになるかな。
  • 次にModelをふたつ作成。DEPARTMENTに複数のMEMBERがぶら下がるという関係。まずはDEPARTMENT
    package shin1o;

import java.util.Vector;
import jpersist.PersistentObject;

@SuppressWarnings("serial")
public class Department extends PersistentObject {
  Long departmentId;

  String name;

  Vector<Member> members = new Vector<Member>();

  public Department() {}

  public Department(String _name) { name = _name; }

  public String toString() {
    return new StringBuilder().append("{id:").append(departmentId).append(
        ", name:").append(name).append(", members:").append(
        members.toString()).append("}}").toString();
  }

  // Associations

  public Vector<Member> getDbAssociation(Member c) {
    return members;
  }

  public void setDbAssociation(Member c, Vector<Member> _members) {
    members = _members;
  }

  public Vector<Member> getMembers() { return members; }

  public void setMembers(Vector<Member> members) { this.members = members; }

  public Long getDepartmentId() { return departmentId; }

  public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; }

  public String getName() { return name; }

  public void setName(String name) { this.name = name; }
}
  • 次にぶら下がる方のMember。
    package shin1o;

import jpersist.PersistentObject;

@SuppressWarnings("serial")
public class Member extends PersistentObject {
  Long memberId;

  String name;

  Long departmentId;

  public Member() { }

  public Member(String _name) { name = _name; }

  public String toString() {
    return new StringBuilder().append("{id:").append(memberId).append(
        ", departmentId:").append(departmentId).append(", name:")
        .append(name).append("}").toString();
  }

  public Long getMemberId() { return memberId; }

  public void setMemberId(Long memberId) { this.memberId = memberId; }

  public String getName() { return name; }

  public void setName(String _name) { this.name = _name; }

  public Long getDepartmentId() { return departmentId; }

  public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; }
}
  • TestClassを作成して、動作確認をしてみる。
    package shin1o;

import static org.junit.Assert.assertEquals;

import java.util.*;
import jpersist.*;
import org.junit.*;

public class JPersistTest {
  static DatabaseManager dbm;

  @BeforeClass
  public static void setUp() throws JPersistException {
    DatabaseManager.setLogLevel(java.util.logging.Level.INFO);
    dbm = DatabaseManager
        .getXmlDefinedDatabaseManager("studyJPersist_hsqldb");
  }

  @AfterClass
  public static void tearDown() throws JPersistException {
    if (dbm != null && !dbm.isClosed()) {
      dbm.close();
    }
  }

  /**
   * {@link #before()} で作成したDepartmentのidを毎回保存しておく。
   */
  Long d0Id, d1Id, d2Id;

  /**
   * Testするたびに初期データを作り直す。
   * @throws Exception
   */
  @Before
  public void before() throws Exception {
    Department d0 = new Department("department0");
    d0.save(dbm);
    d0Id = d0.getDepartmentId(); // save後にIDを保存。

    Department d1 = new Department("department1");
    d1.getMembers().add(new Member("member_1_1"));
    d1.getMembers().add(new Member("member_1_2"));
    d1.getMembers().add(new Member("member_1_3"));
    d1.save(dbm);
    d1Id = d1.getDepartmentId();

    Department d2 = new Department("department2");
    d2.getMembers().add(new Member("member_2_1"));
    d2.getMembers().add(new Member("member_2_2"));
    d2.save(dbm);
    d2Id = d2.getDepartmentId();
  }

  @After
  public void after() throws Exception {
    // 全部消す
    Result<Department> departments = dbm.getDatabase().queryObject(
        Department.class);
    while (departments.hasNext()) {
      Department department = departments.next();
      dbm.getDatabase().deleteObject(department);
    }
  }

  @Test
  public void 一件load_ClassとSql条件() throws Exception {
    Department department = dbm.loadObject(Department.class,
        "where :departmentId = '" + d1Id + "'");
    assertEquals(d1Id, department.getDepartmentId());
    assertEquals(3, department.getMembers().size());
  }

  @Test
  public void 一件load_ClassとSql条件とパラメタ() throws Exception {
    Department department = dbm.loadObject(Department.class,
        "where :name like ?", "%1");
    assertEquals(d1Id, department.getDepartmentId());
  }

  @Test
  public void 一件load_Object() throws Exception {
    Department department = dbm.loadObject(new Department("%1"));
    assertEquals(d1Id, department.getDepartmentId());
  }

  @Test
  public void 全件取得() throws Exception {
    Collection<Department> departments = dbm.loadObjects(
        new ArrayList<Department>(), Department.class);
    assertEquals(3, departments.size());
    Collection<Member> members = dbm.loadObjects(new ArrayList<Member>(),
        Member.class);
    assertEquals(5, members.size());
  }

  @Test
  public void 複数件load_ClassとSql条件とパラメタ() throws Exception {
    Collection<Department> departments = dbm.loadObjects(
        new ArrayList<Department>(), Department.class,
        "where :name like ?", "dep%");
    assertEquals(3, departments.size());
  }

  @Test
  public void transactionManagerを使う() throws Exception {
    TransactionManager transaction = new TransactionManager(dbm) {
      Collection<Department> departments;
      final String sql = "where :name like 'dep%'";

      public void run() throws JPersistException { // 最初は3件。
        departments =

        dbm.loadObjects(new ArrayList<Department>(), Department.class,
            sql);
        assertEquals(3, departments.size());

        new Department("department_a").save(this);
        commit(); // 1件追加したから4件のはず。
        departments = loadObjects(Department.class, sql);
        assertEquals(4, departments.size());

        new Department("department_b").save(this); // さらに1件追加したから5件のはず。
        departments = loadObjects(Department.class, sql);
        assertEquals(5, departments.size());

        rollback(); // rollbackしたから4件のはず。
        departments = loadObjects(Department.class, sql);
        assertEquals(4, departments.size());
      }
    };
    transaction.executeTransaction();
  }

  @Test
  public void 一件delete() throws Exception {
    Department department = dbm.loadObject(Department.class,
        "where :departmentId = '" + d2Id + "'");
    dbm.deleteObject(department);

    Collection<Department> departments = loadObjects(Department.class);
    assertEquals(2, departments.size()); // delete cascadeでmemberも減っているはず。
    Collection<Member> members = loadObjects(Member.class);
    assertEquals(3, members.size());
  }
  
  <T> Collection<T> loadObjects(Class<T> c) throws JPersistException {
    return dbm.loadObjects(new ArrayList<T>(), c);
  }

  <T> Collection<T> loadObjects(Class<T> c, String sql)
      throws JPersistException {
    return dbm.loadObjects(new ArrayList<T>(), c, sql);
  }
}
サンプルを元に単純な例を試すとこんなカンジに使うことになる。ModelがPOJOでないのが引っかかるけど、かなり簡単。Modelに[「get|set]Associations()」を追加するのがポイント。 ちなみに、注意点として「Modelにプリミティブな型を使わない」といぅこと！プリミティブな型はnullを表現できないため、自動的に関連先を取得する時のSQLの条件にプリミティブなフィールドが含まれていまい、正しく関連先が取得できません！俺ハマったよ！ この状態で、SingleTableInheritanceを試そうとしたけど、PDFのドキュメントにある「jpersist.interface.SingleInheritance」が存在しなかったりで苦戦中。また後日チャレンジする。
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