table.java

一个OR Mapping工具

//-< Table.java >----------------------------------------------------*--------*
// JORA                       Version 2.0        (c) 1998  GARRET    *     ?  *
// (Java Object Relational Adapter)                                  *   /\|  *
//                                                                   *  /  \  *
//                          Created:     10-Jun-98    K.A. Knizhnik  * / [] \ *
//                          Last update: 20-Jun-98    K.A. Knizhnik  * GARRET *
//-------------------------------------------------------------------*--------*
// Class representing database table
//-------------------------------------------------------------------*--------*

package jora;

import java.util.*;
import java.sql.*;
import java.lang.reflect.*;

/** Table class is used to establish mapping between corteges of database
 *  tables and Java classes. This class is responsible for constructing
 *  SQL statements for extracting, updating and deleting records of the
 *  database table. 
 */
public class Table { 
    /** Constructor for table object. Make association between Java class 
     *  and database table.
     *  
     * @param tclassName name of Java class
     * @param tableName name of database table mapped on this Java class
     * @param key table's primary key. This parameter is used in UPDATE/DELETE
     *  operations to locate record in the table.
     * @s session, which should be opened before first access to the table
     */
    public Table(String className, String tableName, Session s, String key) {
	String[] keys = {key};
	init(className, tableName, s, keys);
    }

    /** Constructor for table object. Make association between Java class 
     *  and database table.
     *  
     * @param tclassName name of Java class
     * @param tableName name of database table mapped on this Java class
     * @param keys table primary keys. This parameter is used in UPDATE/DELETE
     *  operations to locate record in the table.
     * @s session, which should be opened before first access to the table
     */
    public Table(String className, String tableName, Session s, String[] keys) 
    { 
	init(className, tableName, s, keys);
    }

    /** Constructor for table object. Make association between Java class 
     *  and database table. Name of Java class should be the same as name of 
     *  the database table
     *  
     * @param className name of Java class, which should be (without 
     *  package prefix) be the same as the name of database table.
     * @param keys table primary keys. This parameter is used in UPDATE/DELETE
     *  operations to locate record in the table.
     * @s session, which should be opened before first access to the table
     */
    public Table(String className, Session s, String[] keys) {
        init(className, className.substring(className.lastIndexOf('.')+1),
	     s, keys);
    }

    /** Constructor for table object. Make association between Java class 
     *  and database table. Name of Java class should be the same as name of 
     *  the database table
     *  
     * @param className name of Java class, which should be (without 
     *  package prefix) be the same as the name of database table.
     * @param key table primary key. This parameter is used in UPDATE/DELETE
     *  operations to locate record in the table.
     * @s session, which should be opened before first access to the table
     */
    public Table(String className, Session s, String key) {
	String[] keys = {key};
        init(className, className.substring(className.lastIndexOf('.')+1),
	     s, keys);
    }

    /** Constructor of table without explicit key specification.
     *  Specification of key is necessary for update/remove operations. 
     *  If key is not specified, it is inherited from base table (if any).
     */
    public Table(String className, Session s) {
        init(className, className.substring(className.lastIndexOf('.')+1),
	     s, null);
    }


    /** Constructor of table with "key" and "session" parameters inherited 
     *  from base table. 
     */
    public Table(String className) {
        init(className, className.substring(className.lastIndexOf('.')+1),
	     null, null);
    }


    /** Select records from database table according to search condition
     * 
     * @param condition valid SQL condition expression started with WHERE
     *  or empty string if all records should be fetched.
     */
    public final Cursor select(String condition) { 
        return new Cursor(this, session, 1, condition);
    }

    /** Select records from database table according to search condition
     * 
     * @param condition valid SQL condition expression started with WHERE
     *  or empty string if all records should be fetched.
     * @param session user database session
     */
    public final Cursor select(String condition, Session session) { 
        return new Cursor(this, session, 1, condition);
    }

    /** Select records from specified and derived database tables
     * 
     * @param condition valid SQL condition expression started with WHERE
     *  or empty string if all records should be fetched.
     */
    public final Cursor selectAll(String condition) { 
        return new Cursor(this, session, nDerived+1, condition);
    }

    /** Select records from specified and derived database tables
     * 
     * @param condition valid SQL condition expression started with WHERE
     *  or empty string if all records should be fetched.
     * @param session user database session
     */
    public final Cursor selectAll(String condition, Session session) { 
        return new Cursor(this, session, nDerived+1, condition);
    }

    
    /** Select records from database table using <I>obj</I> object as 
     * template for selection. All non-builtin fields of this object,
     * which are not null, are compared with correspondent table values.
     * 
     * @param obj object for construction search condition: selected objects
     *  should match all non-null fields of specified object.
     */
    public final Cursor queryByExample(Object obj) { 
        return new Cursor(this, session, 1, obj);
    }

    /** Select records from database table using <I>obj</I> object as 
     * template for selection. All non-builtin fields of this object,
     * which are not null, are compared with correspondent table values.
     * 
     * @param obj object for construction search condition: selected objects
     *  should match all non-null fields of specified object.
     * @param session user database session
     */
    public final Cursor queryByExample(Object obj, Session session) { 
        return new Cursor(this, session, 1, obj);
    }

    /** Select records from specified and derived database tables using 
     * <I>obj</I> object as template for selection. 
     * All non-builtin fields of this object,
     * which are not null, are compared with correspondent table values.
     * 
     * @param obj object for construction search condition: selected objects
     *  should match all non-null fields of specified object.
     */
    public final Cursor queryAllByExample(Object obj) { 
        return new Cursor(this, session, nDerived+1, obj);
    }

    /** Select records from specified and derived database tables using 
     * <I>obj</I> object as template for selection. 
     * All non-builtin fields of this object,
     * which are not null, are compared with correspondent table values.
     * 
     * @param obj object for construction search condition: selected objects
     *  should match all non-null fields of specified object.
     * @param session user database session
     */
    public final Cursor queryAllByExample(Object obj, Session session) { 
        return new Cursor(this, session, nDerived+1, obj);
    }

    /** Insert new record in the table. Values of inserted record fields 
     *  are taken from specifed object.
     * 
     * @param obj object specifing values of inserted record fields
     */
    public void insert(Object obj) { 
	insert(obj, session);
    }

    /** Insert new record in the table using specified database session. 
     *  Values of inserted record fields 
     *  are taken from specifed object.
     * 
     * @param obj object specifing values of inserted record fields
     * @param session user database session
     */
    public synchronized void insert(Object obj, Session session) { 
	if (session == null) { 
	    session = ((SessionThread)Thread.currentThread()).session;
	}
        try { 
	    checkConnection(session);
	    if (insertStmt == null) { 
	        String sql = "insert into " + name + " (" 
                           + listOfFields + ") values (?";
		for (int i = 1; i < nColumns; i++) {   
                     sql += ",?";
		}
		sql += ")";
	        insertStmt = session.connection.prepareStatement(sql);
   	    }
	    bindUpdateVariables(insertStmt, obj); 	
	    insertStmt.executeUpdate();
	    insertStmt.clearParameters();
	} catch(SQLException ex) { session.handleSQLException(ex); }
    }

    /** Insert several new records in the table. Values of inserted records 
     *  fields are taken from objects of specified array.
     * 
     * @param objects array with objects specifing values of inserted record 
     * fields
     */
    public void insert(Object[] objects) { 
	insert(objects, session);
    }
  
    /** Insert several new records in the table. Values of inserted records 
     *  fields are taken from objects of specified array.
     * 
     * @param objects array with objects specifing values of inserted record 
     *                fields
     * @param session user database session
     */
    public synchronized void insert(Object[] objects, Session session) { 
	if (session == null) { 
	    session = ((SessionThread)Thread.currentThread()).session;
	}
        try { 
	    checkConnection(session);
	    if (insertStmt == null) { 
	        String sql = "insert into " + name + " (" 
                           + listOfFields + ") values (?";
		for (int i = 1; i < nColumns; i++) {   
                     sql += ",?";
		}
		sql += ")";
	        insertStmt = session.connection.prepareStatement(sql);
   	    }
	    for (int i = 0; i < objects.length; i++) { 
  	        bindUpdateVariables(insertStmt, objects[i]); 
	        insertStmt.addBatch();
	    }
	    insertStmt.executeBatch();
	    insertStmt.clearParameters();
	} catch(SQLException ex) { session.handleSQLException(ex); }
    }
  
    /** Update record in the table using table's primary key to locate 
     *  record in the table and values of fields of specified object <I>obj</I>
     *  to alter record fields.
     * 
     * @param obj object specifing value of primary key and new values of 
     *  updated record fields
     * 
     * @return number of objects actually updated
    */
    public int update(Object obj) { 
	return update(obj, session);
    }

    /** Update record in the table using table's primary key to locate 
     *  record in the table and values of fields of specified object <I>obj</I>
     *  to alter record fields.
     * 
     * @param obj object specifing value of primary key and new values of 
     *  updated record fields
     * @param session user database session
     * 
     * @return number of objects actually updated
     */
    public synchronized int update(Object obj, Session session) { 
        if (primaryKeys == null) { 
	    throw new NoPrimaryKeyError(this);
	}
	if (session == null) { 
	    session = ((SessionThread)Thread.currentThread()).session;
	}
	int nUpdated = 0;
        try { 
	    checkConnection(session);
	    if (updateStmt == null) { 
	        String sql = "update " + name + " set " + listOfAssignments 
		           + " where " + primaryKeys[0] + " = ?"; 
		for (int i = 1; i < primaryKeys.length; i++) { 
		    sql += " and " + primaryKeys[i] + " = ?";
		}
		updateStmt = session.connection.prepareStatement(sql);
	    }
	    for (int i = 0; i < primaryKeys.length; i++) { 
		fields[primaryKeyIndices[i]].bindVariable(updateStmt, obj, 
							  nColumns+i+1);
	    } 	
	    bindUpdateVariables(updateStmt, obj); 
	    nUpdated = updateStmt.executeUpdate();
	    updateStmt.clearParameters();
	} catch(SQLException ex) { session.handleSQLException(ex); }
	return nUpdated;
    }

    /** Update set of records in the table using table's primary key to locate