// JdbcBeanSerializer.java
// $Id: JdbcBeanSerializer.java,v 1.11 2000/08/02 11:54:54 bmahe Exp $
// (c) COPYRIGHT MIT, INRIA and Keio, 2000.
// Please first read the full copyright statement in file COPYRIGHT.html
package org.w3c.tools.jdbc;

import java.beans.BeanInfo;
import java.beans.Beans;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyDescriptor;

import java.io.IOException;

import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Properties;
import java.util.Vector;

import org.w3c.tools.jdbc.JdbcServer;

/**
 * @version $Revision: 1.11 $
 * @author  Benoît Mahé (bmahe@w3.org)
 */
public class JdbcBeanSerializer implements PropertyChangeListener {
    
    /**
     * Bean modified?
     */
    protected boolean modified = false;

    /**
     * Our bean.
     */
    protected JdbcBeanInterface bean = null;

    /**
     * The associated JdbcBean
     */
    protected JdbcBeanInterface beans[] = null;

    /**
     * INTERSECT, UNION, EXCEPT.
     */
    protected final static int NOTHING   = -1;
    protected final static int INTERSECT = 10;
    protected final static int UNION     = 20;
    protected final static int EXCEPT    = 30;

    protected int priority[] = { NOTHING, NOTHING, NOTHING };

    protected JdbcBeanSerializer intersect_serializer = null;
    protected JdbcBeanSerializer union_serializer     = null;
    protected JdbcBeanSerializer except_serializer    = null;

    /**
     * The ResultSet
     */
    protected ResultSet result = null;

    /**
     * The tables/bean used to generate the SQL request (in the correct
     * order)
     */
    protected Vector beantables = null;

    /**
     * The Foreign keys <(class,class), String[]>
     */
    protected static Hashtable foreignKeys = new Hashtable();

    public static void registerForeignKeys(Class beanclass1, Class beanclass2)
    {
	Integer key = new Integer(beanclass1.hashCode() & 
				  beanclass2.hashCode());
	if (! foreignKeys.containsKey(key)) {
	    foreignKeys.put(key, computeForeignKeys(beanclass1, beanclass2));
	}
    }

    public static String[] getForeignKeys(Class beanclass1,
					  Class beanclass2)
    {
	Integer key = new Integer(beanclass1.hashCode() & 
				  beanclass2.hashCode());
	String keys[] = (String[]) foreignKeys.get(key);
	if (keys == null) {
	    keys = computeForeignKeys(beanclass1, beanclass2);
	    foreignKeys.put(key, keys);
	}
	return keys;
    }

    protected static String[] computeForeignKeys(Class beanclass1,
						 Class beanclass2) 
    {
	try {
	    BeanInfo           bi1    = Introspector.getBeanInfo(beanclass1);
	    PropertyDescriptor pds1[] = bi1.getPropertyDescriptors();

	    BeanInfo           bi2    = Introspector.getBeanInfo(beanclass2);
	    PropertyDescriptor pds2[] = bi2.getPropertyDescriptors();
	
	    Vector foreign = new Vector();
	    
	    for(int cpt1 = 0 ; cpt1 < pds1.length ; cpt1++) {
		PropertyDescriptor pd1 = pds1[cpt1];
		for (int cpt2 = 0 ; cpt2 < pds2.length ; cpt2++) {
		    PropertyDescriptor pd2 = pds2[cpt2];
		    if ((! pd2.isHidden()) 
			&& (! pd1.isHidden())
			&& (equalsForeignKeys(pd1.getName(),pd2.getName()))) {
			foreign.addElement(pd1.getName());
		    }
		}
	    }
	    String keys[] = new String[foreign.size()];
	    foreign.copyInto(keys);
	    return keys;
	} catch (IntrospectionException ex) {
	    return new String[0];
	}
    }

    /**
     * toto_username == username
     */
    protected static boolean equalsForeignKeys(String key1, String key2) {
	int idx1 = key1.lastIndexOf("_");
	if (idx1 != -1) {
	    key1 = key1.substring(idx1);
	}
	int idx2 = key2.lastIndexOf("_");
	if (idx2 != -1) {
	    key2 = key2.substring(idx2);
	}
	return key1.equals(key2);
    }

    protected void markModified(boolean modified) {
	this.modified = modified;
    }

    protected boolean isModified() {
	return modified;
    }

    /**
     * PropertyChangeListener implementation: This method gets called when
     * a bound property is changed.
     * @param evt A PropertyChangeEvent object describing the event source 
     * and the property that has changed.
     */
    public void propertyChange(PropertyChangeEvent evt) {
	Object source = evt.getSource();
	String name   = evt.getPropertyName();
	Object value  = evt.getNewValue();
	if (source == bean) {
	    if (value == null) {
		PropertyDescriptor pd = getPropertyDescriptor(name);
		if (JdbcBeanUtil.isJdbcBean(pd.getPropertyType())) {
		    // delete cached bean descriptors
		    this.beans = null;
		    // update listeners
		    JdbcBeanInterface oldbean = 
			(JdbcBeanInterface)evt.getOldValue();
		    if (oldbean != null) {
			PropertyCache.removeProperties(oldbean);
			oldbean.removePropertyChangeListener(this);
		    }
		}
	    } else if (value instanceof JdbcBeanInterface) {
		registerForeignKeys(bean.getClass(), value.getClass());
		// delete cached bean descriptors
		this.beans = null;
		// update listeners
		JdbcBeanInterface oldbean = 
		    (JdbcBeanInterface)evt.getOldValue();
		JdbcBeanInterface newbean = (JdbcBeanInterface)value;
		if (oldbean != null) {
		    PropertyCache.removeProperties(oldbean);
		    oldbean.removePropertyChangeListener(this);
		}
		newbean.addPropertyChangeListener(this);
	    } else {
		JdbcBeanInterface bean = (JdbcBeanInterface)source;
		PropertyCache.addProperty(bean, name, evt.getNewValue());
		markModified(true);
	    }
	} else {
	    markModified(true);
	}
    }

    /**
     * Get the raw value of the given property, split the operator and
     * the value and convert the raw value into a SQL value.<p>
     * ie "~A.*" will become { " ~ " , "'A.*'" }
     * @param bean the property holder
     * @param pd the property descriptor
     */
    protected String[] getSQLOperatorNValue(JdbcBeanInterface bean, 
					    PropertyDescriptor pd) 
    {
	Class  type = pd.getPropertyType();
	Method m    = pd.getReadMethod(); 
	if (m != null) { // are we authozired to read it?
	    // use the cache
	    Object value = PropertyCache.getProperty(bean, pd); 
	    if (value == null) {
		return null;
	    }
	    return SQL.getSQLOperator(value);
	}
	return null;
    }

    /**
     * Get the SQL value of the given property.
     * @param bean the property holder
     * @param pd the property descriptor
     */
    protected String getSQLValue(JdbcBeanInterface bean, 
				 PropertyDescriptor pd) 
    {
	Class  type = pd.getPropertyType();
	Method m    = pd.getReadMethod(); 
	if (m != null) { // are we authozired to read it?
	    // use the cache
	    Object value = PropertyCache.getProperty(bean, pd); 
	    if (value == null) {
		return null;
	    }
            return SQL.getSQLValue(value);
	}
	return null;
    }

    /**
     * @param name
     * @param value
     * @param buf
     */
    private void append(String name, 
			String operator,
			String value, 
			String separator,
			StringBuffer buf)
    {
	if (buf.length() > 0) {
	    buf.append(separator).append(" ");
	}
	buf.append(name).append(operator).append(value).append(" ");
    }

    /**
     * @param name
     * @param value
     * @param namesbuffer
     * @param valuesbuffer
     */
    private void appendInsert(String name, 
			      String value, 
			      StringBuffer namesbuffer,
			      StringBuffer valuesbuffer)
    {
	if (namesbuffer.length() > 0) {
	    namesbuffer.append(", ").append(name);
	    valuesbuffer.append(", ").append(value);
	} else {
	    namesbuffer.append("(").append(name);
	    valuesbuffer.append("(").append(value);
	}
    }

    protected JdbcBeanInterface[] getJdbcBeans() {
	if (beans != null) {
	    return beans;
	}
	try {
	    BeanInfo info = Introspector.getBeanInfo(bean.getClass());
	    Vector   vb   = new Vector();
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if ((! pd.isHidden()) &&  
		    (JdbcBeanUtil.isJdbcBean(pd.getPropertyType()))) {
		    Method m = pd.getReadMethod();
		    if (m != null) {
			Object value = m.invoke(bean, null);
			if (value != null) {
			    vb.addElement(value);
			}
		    }
		}
	    }
	    beans = new JdbcBeanInterface[vb.size()];
	    vb.copyInto(beans);
	    return beans;
	} catch (IntrospectionException ex) {
	    return null;
	} catch (IllegalAccessException ex) {
	    return null;
	} catch (InvocationTargetException ex) {
	    return null;
	}
    }

    protected void appendForeignKeys(Vector tables,
				     StringBuffer buffer,
				     String properties[]) 
	throws IntrospectionException
    {
	BeanInfo     info   = Introspector.getBeanInfo(bean.getClass());
	PropertyDescriptor pds[] = info.getPropertyDescriptors();
	appendForeignKeys(tables, buffer, pds, properties);
    }

    protected void appendForeignKeys(Vector tables,
				     StringBuffer buffer,
				     PropertyDescriptor pds[],
				     String properties[])
	throws IntrospectionException
    {
	JdbcBeanInterface jbeans[] = getJdbcBeans();
	if (jbeans != null) { // FOREIGN KEYs
	    for (int i = 0 ; i < jbeans.length ; i++) {
		JdbcBeanInterface jbean = jbeans[i];
		// foreign keys
		String keys[] = getForeignKeys(jbean.getClass(),
					       bean.getClass());
		for (int f = 0 ; f < keys.length ; f++) {
		    String key = keys[f];
		    if ((properties == null) ||
			(JdbcBeanUtil.isIn(key, properties))) {
			append(jbean.getJdbcTable()+"."+key,
			       " = ",
			       bean.getJdbcTable()+"."+key,
			       "AND",
			       buffer);
		    }
		}
		BeanInfo           bi     = null;
		PropertyDescriptor jpds[] = null;
		// value now
		bi   = Introspector.getBeanInfo(jbean.getClass());
		jpds = bi.getPropertyDescriptors();
		for (int jpd_cpt = 0 ; jpd_cpt < jpds.length ; jpd_cpt++) {
		    PropertyDescriptor jpd = jpds[jpd_cpt];
		    if (jpd.isHidden()) {
			continue;
		    }
		    String jname = jpd.getName();
		    if ((properties == null) ||
			(JdbcBeanUtil.isIn(jname, properties))) {
			String split[] = getSQLOperatorNValue(jbean, jpd);
			if (split != null) {
			    append(jbean.getJdbcTable()+"."+jname,
				   split[0],
				   split[1],
				   "AND",
				   buffer);
			}
		    }
		}
		tables.addElement(jbean);
		// test FIXME recursive stuff
		jbean.getSerializer().appendForeignKeys(tables, 
							buffer, 
							properties);
	    }
	}
    }

    protected String computeSQLCount(boolean all, 
				     boolean distinct, 
				     String properties[]) 
    {
	String count = (distinct) ? "DISTINCT count(*)" : "count(*)";
	return _computeSQLSelect(all, count, properties);
    }

    protected String computeSQLSelect(String orderby[], 
				      boolean asc[],
				      boolean all)
    {
	return computeSQLSelect(orderby, asc, all, "*", null);
    }

    protected String computeSQLSelect(String orderby[], 
				      boolean asc[],
				      boolean all,
				      String select)
    {
	return computeSQLSelect(orderby, asc, all, select, null);
    }

    protected String computeSQLSelect(String orderby[], 
				      boolean asc[],
				      boolean all,
				      String select,
				      String properties[])
    {
	String sql = _computeSQLSelect(all, select, properties);
	StringBuffer buffer = new StringBuffer(sql);
	if (orderby != null) {
	    buffer.append(" ORDER BY ");
	    for (int j = 0 ; j < orderby.length ; j++) {
		if (j != 0) {
		    buffer.append(", ");
		}
		buffer.append(orderby[j]);
		if (! asc[j]) {
		    buffer.append(" DESC");
		}
	    }
	}
	return buffer.toString();
	
    }

    protected String _computeSQLSelect(boolean all,
				       String select,
				       String properties[])
    {
	try {
	    BeanInfo     info   = Introspector.getBeanInfo(bean.getClass());
	    StringBuffer buffer = new StringBuffer();
	    String       table  = bean.getJdbcTable();
	    this.beantables     = new Vector();
	    beantables.addElement(bean);
	    
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    if (all) {
		// FOREIGN KEYs
		appendForeignKeys(beantables, buffer, pds, properties);
	    }
	    // known values
	    for (int i = 0 ; i < pds.length ; i++) { 
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {
		    String jname = pd.getName();
		    if ((properties == null) ||
			(JdbcBeanUtil.isIn(jname, properties))) {
			String split[] = getSQLOperatorNValue(bean, pd);
			if (split != null) {
			    append(table+"."+jname, 
				   split[0],
				   split[1],
				   "AND",
				   buffer);
			}
		    }
		}
	    }
	    // build SQL request
	    if (buffer.length() > 0) {
		StringBuffer tables = new StringBuffer();
		for (int i = 0 ; i < beantables.size() ; i++) {
		    JdbcBeanInterface jbean = 
			(JdbcBeanInterface)beantables.elementAt(i);
		    if (i != 0) {
			tables.append(", ");
		    }
		    tables.append(jbean.getJdbcTable());
		}
		tables.append(" WHERE ");
		tables.insert(0, "SELECT "+select+" FROM ");
		tables.append(buffer.toString());
		buffer = tables;
	    } else {
		buffer = new StringBuffer("SELECT "+select+" FROM ");
		buffer.append(table);
	    }
	    // union? intersect? except?
	    for (int i = 0 ; i < priority.length ; i++) {
		int p = priority[i];
		if (p == NOTHING) {
		    break;
		}
		switch (p) 
		    {
		    case INTERSECT:
			String intersect = 
			    intersect_serializer._computeSQLSelect(all,
								   select,
								   properties);
			buffer.append(" INTERSECT (").append(intersect);
			buffer.append(")");
			break;
		    case UNION:
			String union = 
			    union_serializer._computeSQLSelect(all,
							       select,
							       properties);
			buffer.append(" UNION (").append(union);
			buffer.append(")");
			break;
		    case EXCEPT:
			String except =
			    except_serializer._computeSQLSelect(all,
								select,
								properties);
			buffer.append(" EXCEPT (").append(except);
			buffer.append(")");
			break;
		    default:
			// unreached (I hope)
		    }
	    }
	    return buffer.toString();
	} catch (IntrospectionException ex) {
	    return null;
	}
    }

    /**
     * Compute the SQL request necessary to update the Database.
     * @return a String
     */
    protected String computeSQLInsert() {
	try {
	    BeanInfo info = Introspector.getBeanInfo(bean.getClass());
	    PropertyDescriptor pds[]  = info.getPropertyDescriptors();
	    StringBuffer namesbuffer  = new StringBuffer();
	    StringBuffer valuesbuffer = new StringBuffer();
	    for (int i = 0 ; i < pds.length ; i++) { 
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {	
		    String value = getSQLValue(bean, pd);
		    if (value != null) {
			appendInsert(pd.getName(), 
				     value, 
				     namesbuffer, 
				     valuesbuffer);
		    }
		}
	    }
	    if (namesbuffer.length() > 0) {
		StringBuffer request = new StringBuffer("INSERT INTO ");
		request.append(bean.getJdbcTable()).append(" ");
		request.append(namesbuffer).append(") ");
		request.append("VALUES ").append(valuesbuffer).append(")");
		return request.toString();
	    } else {
		return null;
	    }
	} catch (IntrospectionException ex) {
	    return null;
	}
    }

    protected String computeSQLDelete() {
	try {
	    BeanInfo     info   = Introspector.getBeanInfo(bean.getClass());
	    StringBuffer buffer = new StringBuffer();
	    StringBuffer table = new StringBuffer(bean.getJdbcTable());
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    // known values
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {
		    String split[] = getSQLOperatorNValue(bean, pd);
		    if (split != null) {
			append(pd.getName(), split[0], split[1],"AND", buffer);
		    }
		}
	    }
	    // build SQL request
	    if (buffer.length() > 0) {
		table.append(" WHERE ");
		table.insert(0, "DELETE FROM ");
		table.append(buffer.toString());
		buffer = table;
	    } else {
		return null;
	    }
	    return buffer.toString();
	} catch (IntrospectionException ex) {
	    return null;
	}
    }

    protected String computeSQLUpdate(String primarykeys[]) {
	try {
	    BeanInfo     info     = Introspector.getBeanInfo(bean.getClass());
	    StringBuffer buffer   = new StringBuffer();
	    StringBuffer pkbuffer = new StringBuffer();
	    StringBuffer table    = new StringBuffer(bean.getJdbcTable());
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    // known values
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {
		    String name = pd.getName();
		    String split[] = getSQLOperatorNValue(bean, pd);
		    if (split != null) {
			if (JdbcBeanUtil.isIn(name, primarykeys)) {
			    append(name, split[0], split[1], "AND", pkbuffer);
			} else {
			    append(name, split[0], split[1], ",", buffer);
			}
		    }
		}
	    }
	    // build SQL request
	    if (buffer.length() > 0) {
		table.append(" SET ");
		table.insert(0, "UPDATE ");
		table.append(buffer.toString());
		table.append(" WHERE ");
		table.append(pkbuffer.toString());
		buffer = table;
	    } else {
		return null;
	    }
	    return buffer.toString();
	} catch (IntrospectionException ex) {
	    return null;
	}
    }

    protected JdbcServer getJdbcServer() {
	Properties props = new Properties();
	Jdbc.setMaxConn(props, bean.getMaxConn());
	return JdbcServer.getServer(bean.getJdbcURI(), 
				    bean.getJdbcUser(), 
				    bean.getJdbcPassword(), 
				    bean.getJdbcDriver(), 
				    props);
    }

    protected void executeSQLQuery(String sqlrequest) 
	throws SQLException
    {
	result = getJdbcServer().runQuery(sqlrequest, false);
    }

    protected int executeSQLUpdate(String sqlrequest) 
	throws SQLException
    {
	return getJdbcServer().runUpdate(sqlrequest, false);
    }
    
    public boolean exists() {
	return (count() == 1);
    }

    /**
     * Count the number or row with columns matching the value of the
     * bean properties.
     * @return an int
     */
    public int count() {
	return count(true, false, null);
    }

    /**
     * Count the number or row with columns matching the value of the
     * given properties.
     * @param properties The property names
     * @return an int
     */
    public int count(String properties[]) {
	return count(true, false, properties);
    }

    /**
     * Count the number or row with columns matching the value of the
     * bean properties.
     * @param all (join with associated beans?)
     * @return an int
     */
    public int count(boolean all) {
	return count(all, false, null);
    }

    /**
     * Count the number or row with columns matching the value of the
     * bean properties
     * @param all (join with associated beans?)
     * @param distinct (SELECT DISTINCT?)
     * @return an int
     */
    public int count(boolean all, boolean distinct) {
	return count(all, distinct, null);
    }

    /**
     * Count the number or row with columns matching the value of the
     * given properties.
     * @param all (join with associated beans?)
     * @param distinct (SELECT DISTINCT?)
     * @param properties The property names
     * @return an int
     */
    public int count(boolean all, boolean distinct, String properties[]) {
	String sql = computeSQLCount(all, distinct, properties);
	try {
	    executeSQLQuery(sql);
	    if (result.first()) {
		return result.getInt(1);
	    } else {
		return 0;
	    }
	} catch (SQLException ex) {
	    System.out.println("SQL STATE: "+ex.getSQLState());
	    ex.printStackTrace();
	    return 0;
	} finally {
	    result     = null;
	    beantables = null;
	}
	
    }

    /**
     * Perform a sql select to update the beans properties.
     */
    public void select() {
	boolean array[] = { true };
	select((String[])null, array, true, false);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param all join with attached beans? (default is true)
     */
    public void select(boolean all) {
	boolean array[] = { true };
	select((String[])null, array, all, false);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby orderby rule
     */
    public void select(String orderby) {
	String array[] = { orderby };
	boolean arrayb[] = { true };
	select(array, arrayb, true, false);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby orderby rule
     * @param asc boolean if true orderby is ASC if false it it
     * DESC (relative to the orderby[] parameter)
     * @param all join with attached beans? (default is true)
     */
    public void select(String orderby, 
		       boolean asc, 
		       boolean all)
    {
	String array[] = { orderby };
	boolean arrayb[] = { asc };
	select(array, arrayb, all, false);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby orderby rule
     * @param asc boolean if true orderby is ASC if false it it
     * DESC (relative to the orderby[] parameter)
     * @param all join with attached beans? (default is true)
     * @param distinct if true, result won't have duplicate row (default is 
     * false)
     */
    public void select(String orderby, 
		       boolean asc, 
		       boolean all, 
		       boolean distinct) 
    {
	String array[] = { orderby };
	boolean arrayb[] = { asc };
	select(array, arrayb, all, distinct);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby array of orderby rules (ASC by default)
     */
    public void select(String orderby[]) {
	boolean array[] = { true };
	select(orderby, array, true, false);
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby array of orderby rules
     * @param asc array of boolean if true orderby is ASC if false it it
     * DESC (relative to the orderby[] parameter)
     * @param all join with attached beans? (default is true)
     * @param distinct if true, result won't have duplicate row (default is 
     * false)
     */
    public void select(String orderby[],
		       boolean asc[],
		       boolean all,
		       boolean distinct) 
    {
	String select = (distinct) ? "DISTINCT *" : "*";
	String sql = computeSQLSelect(orderby, asc, all, select);
	try {
	    executeSQLQuery(sql);
	} catch (SQLException ex) {
	    System.out.println("SQL STATE: "+ex.getSQLState());
	    ex.printStackTrace();
	    result = null;
	}
    }

    /**
     * Perform a sql select to update the beans properties.
     * @param orderby array of orderby rules
     * @param asc array of boolean if true orderby is ASC if false it it
     * DESC (relative to the orderby[] parameter)
     * @param all join with attached beans? (default is true)
     * @param distinct if true, result won't have duplicate row (default is 
     * @param toselect array of columns name to select
     * false)
     */
    public void select(String orderby[],
		       boolean asc[],
		       boolean all,
		       boolean distinct,
		       String toselect[]) 
    {
	String query = null;
	if (toselect != null) {
	    StringBuffer buffer = new StringBuffer();
	    for (int i = 0 ; i < toselect.length ; i++) { 
		if (i != 0) {
		    buffer.append(", ");
		}
		buffer.append(toselect[i]).append(" ");
	    }
	    query = buffer.toString();
	} else {
	    query = "*";
	}
	String select = (distinct) ? "DISTINCT "+query : query;
	String sql = computeSQLSelect(orderby, asc, all, select);
	try {
	    executeSQLQuery(sql);
	} catch (SQLException ex) {
	    System.out.println("SQL STATE: "+ex.getSQLState());
	    ex.printStackTrace();
	    result = null;
	}
    }

    /**
     * Perform a sql select to update only the given columns. (distinct flag is
     * set as true.
     * @param column the bean property to update
     */
    public void selectDistinct(String column) {
	boolean array[] = { true };
        String order[] = { column };
	String sql = computeSQLSelect(order, array, false, "DISTINCT "+column);
	try {
	    executeSQLQuery(sql);
	} catch (SQLException ex) {
	    System.out.println("SQL STATE: "+ex.getSQLState());
	    ex.printStackTrace();
	    result = null;
	}
    }

    protected void setPriority(int p) {
	int idx = 0;
	while ((idx < priority.length) && (priority[idx] != NOTHING)) {
	    if (priority[idx] == p) { // already set
		return;
	    }
	    idx++;
	}
	priority[idx] = p;
    }

    public JdbcBeanSerializer intersect(JdbcBeanInterface ibean) {
	setPriority(INTERSECT);
	intersect_serializer = ibean.getSerializer();
	return intersect_serializer;
    }

    public JdbcBeanSerializer union(JdbcBeanInterface ubean) {
	setPriority(UNION);
	union_serializer = ubean.getSerializer();
	return union_serializer;
    }

    public JdbcBeanSerializer except(JdbcBeanInterface ebean) {
	setPriority(EXCEPT);
	except_serializer = ebean.getSerializer();
	return except_serializer;
    }

    public boolean insert() {
	if (! isModified()) { // nothing new to insert
	    return false;
	}
	JdbcBeanInterface beans[] = getJdbcBeans();
	for (int i = 0 ; i < beans.length ; i++) { 
	    JdbcBeanInterface jbean = beans[i];
	    JdbcBeanSerializer ser  = jbean.getSerializer();
	    if (ser.isModified()) {
		// insert associated bean
		ser.insert();
		// update our foreign key
		updateForeignKeys(jbean); 
	    }
	}
	if (! bean.getReadOnly()) {
	    // ok insert ourself now
	    String request = computeSQLInsert();
	    try {
		// insert (could fail without being critical)
		// ie: when the row is already in the table
		executeSQLUpdate(request);
	    } catch (SQLException ex) {
		System.err.println(ex.getMessage());
	    }
	}
	// update value automatically generated by the DB (index, ...)
	select(false);
	try {
	    if (result == null) {
		return false;
	    }
	    if (result.first()) {
		return updateProperties(false);
	    } else {
		return false;
	    }
	} catch (SQLException ex) {
	    ex.printStackTrace();
	    return false;
	}
    }

    public boolean update(String primarykey) {
	String array[] = { primarykey };
	return update(array);
    }

    public boolean update(String primarykeys[]) {
	if (! isModified()) { // noting to update
	    return false;
	}
// 	JdbcBeanInterface beans[] = getJdbcBeans();
// 	for (int i = 0 ; i < beans.length ; i++) { 
// 	    JdbcBeanInterface jbean = beans[i];
// 	    JdbcBeanSerializer ser  = jbean.getSerializer();
// 	    if (ser.isModified()) {
// 		// insert associated bean
// 		ser.insert();
// 		// update our foreign key
// 		updateForeignKeys(jbean);
// 	    }
// 	}
	String sql = computeSQLUpdate(primarykeys);
	try {
	    int nb = executeSQLUpdate(sql);
	    return (nb > 0);
	} catch (SQLException ex) {
	    ex.printStackTrace();
	}
	return false;
    }

    public boolean delete() {
	if (bean.getReadOnly()) {
	    return false;
	}
	String sql = computeSQLDelete();
	try {
	    int nb = executeSQLUpdate(sql);
	    return (nb > 0);
	} catch (SQLException ex) {
	    System.out.println("SQL STATE: "+ex.getSQLState());
	    ex.printStackTrace();
	    result = null;
	    return false; // FIXME VERIFY
	}
    }

    /**
     * Go to the first row
     * @return false if there is no first row
     */
    public boolean first() {
	try {
	    if (result == null) {
		return false;
	    }
	    if (result.first()) {
		return updateProperties();
	    }
	} catch (SQLException ex) { }
	return false;
    }

    /**
     * Update our bean with the value of the next row
     * @return false if there is no more row
     */
    public boolean next() {
	try {
	    if (result == null) {
		return false;
	    }
	    if (result.next()) {
		return updateProperties();
	    }
	} catch (SQLException ex) { }
	return false;
    }

    public boolean isLast() {
	try {
	    if (result == null) {
		return true;
	    }
	    return result.isLast();
	} catch (SQLException ex) { }
	return true;
    }

    /**
     * Clean cached properties (relative to our bean)
     */
    public void clean() {
	result = null;
	PropertyCache.removeProperties(bean);
        markModified(false);
    }

    /**
     * Restore default value except for JdbcBean properties.
     */
    public void initBean() {
	try {
	    BeanInfo info = Introspector.getBeanInfo(bean.getClass());
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if ((! pd.isHidden()) && 
		    (! JdbcBeanUtil.isJdbcBean(pd.getPropertyType()))) {
		    Method getter = pd.getReadMethod();
		    Method setter = pd.getWriteMethod();
		    Object value  = null;
		    if ((getter != null) && (setter != null)) {
			try {
			    value = getter.invoke(bean.getDefault(), null);
			    Object array[] = { value };
			    setter.invoke(bean, array);
			} catch (IllegalAccessException ex) {
			    ex.printStackTrace();
			    // nothing to do
			} catch (InvocationTargetException ex) {
			    ex.printStackTrace();
			    // still nothing to do
			} catch (IllegalArgumentException ex) {
			    ex.printStackTrace();
			    // nothing to do
			}
		    }  
		}
	    }
	    clean();
	} catch (IntrospectionException ex) {
	}
    }

    protected int findColumn(Vector tables, ResultSet result, String colname) 
	throws SQLException
    {
	String            tablename = bean.getJdbcTable();
	ResultSetMetaData metadata  = result.getMetaData();
	int cpt = 0;
	if (metadata.getTableName(0).length() > 0) { // applicable
	    for (int i = 0 ; i < metadata.getColumnCount() ; i++) {
		String coltable = metadata.getTableName(i);
		if ((metadata.getTableName(i).equals(tablename)) &&
		    (metadata.getColumnName(i).equals(colname))) {
		    return i;
		}
	    }
	} else { // not applicable
	    // search all columns matching the given name
	    Vector indexes = new Vector();
	    try {
		for (int i = 1 ; i <= metadata.getColumnCount() ; i++) {
		    if (metadata.getColumnName(i).equals(colname)) {
			indexes.addElement(new Integer(i));
		    }
		}
	    } catch (Exception ex) {
		ex.printStackTrace();
	    }
	    // find the good one
	    if (indexes.size() == 0) {
		return -1;
	    } else if (indexes.size() == 1) {
		return ((Integer)indexes.elementAt(0)).intValue();
	    } else {
		int idxidx = 0;
		for (int i = 0 ; i < tables.size() ; i++) {
		    JdbcBeanInterface jbean = 
			(JdbcBeanInterface)tables.elementAt(i);
		    if (jbean == bean) {
			return ((Integer)indexes.elementAt(idxidx)).intValue();
		    }
		    if (jbean.getSerializer().getPropertyDescriptor(colname) !=
			null) {
			// exists in this table
			idxidx++;
		    }
		}
	    }
	}
	return -1;
    }

    protected boolean updateProperties() {
	return updateProperties(this.beantables, this.result, true);
    }

    protected boolean updateProperties(boolean all) {
	return updateProperties(this.beantables, this.result, all);
    }

    protected boolean updateProperties(Vector tables,
				       ResultSet result) 
    {
	return updateProperties(tables, result, true);
    }

    protected boolean updateProperties(Vector tables,
				       ResultSet result, 
				       boolean all) 
    {
	try {
	    BeanInfo info = Introspector.getBeanInfo(bean.getClass());
	    PropertyDescriptor pds[] = info.getPropertyDescriptors();
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {
		    try {
			int idx = findColumn(tables, result, pd.getName());
			if (idx != -1) {
			    Object value  = result.getObject(idx);
			    Class propertyclass = pd.getPropertyType();
			    value = SQL.getMatchingValue(propertyclass, value);
			    if (value != null) {
				Object values[] = { value };
				Method setter = pd.getWriteMethod();
				if (setter != null) {
				    try {
					setter.invoke(bean, values);
				    } catch (IllegalAccessException ex) {
					ex.printStackTrace();
					// nothing to do
				    } catch (InvocationTargetException ex) {
					ex.printStackTrace();
					// still nothing to do
				    } catch (IllegalArgumentException ex) {
					ex.printStackTrace();
					// nothing to do
				    }
				}
			    } else {
				// default value
				Method getter = pd.getReadMethod();
				Method setter = pd.getWriteMethod();
				if ((getter != null) && (setter != null)) {
				    try {
					value = 
					    getter.invoke(bean.getDefault(),
							  null);
					Object array[] = { value };
					setter.invoke(bean, array);
				    } catch (IllegalAccessException ex) {
					ex.printStackTrace();
					// nothing to do
				    } catch (InvocationTargetException ex) {
					ex.printStackTrace();
					// still nothing to do
				    } catch (IllegalArgumentException ex) {
					ex.printStackTrace();
					// nothing to do
				    }
				}
			    }
			}
		    } catch (SQLException ex) { // not found
			// nothing to do
		    }
		}
	    }
	    if (all) {
		// update the associated beans
		JdbcBeanInterface beans[] = getJdbcBeans();
		for (int i = 0 ; i < beans.length ; i++) {
		    beans[i].getSerializer().updateProperties(tables, result);
		}
	    }
	    markModified(false);
	    return true;
	} catch (IntrospectionException ex) {
	    return false;
	}
    }

    /**
     * Update our bean property with the given bean property 
     * (must be an instance of the same class).
     * @param ubean the bean to get new properties
     */
    public void updateProperties(JdbcBeanInterface ubean) {
	if (ubean.getClass() != bean.getClass()) {
	    return;
	}
	try {
	    BeanInfo bi = Introspector.getBeanInfo(bean.getClass());
	    PropertyDescriptor pds[] = bi.getPropertyDescriptors();
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if (! pd.isHidden()) {
		    try {
			Method reader = pd.getReadMethod();
			Method writer = pd.getWriteMethod();
			Object value  = reader.invoke(ubean, null);
			if (value != null) {
			    Object array[] = { value };
			    writer.invoke(bean, array);
			}
		    } catch (IllegalAccessException ex) {
			ex.printStackTrace();
		    } catch (InvocationTargetException ex) {
			ex.printStackTrace();
		    }
		}
	    }
	} catch (IntrospectionException ex) {
	    // nothing to do
	}
    }

    protected PropertyDescriptor getPropertyDescriptor(String property) {
	try {
	    BeanInfo bi = Introspector.getBeanInfo(bean.getClass());
	    PropertyDescriptor pds[] = bi.getPropertyDescriptors();
	    for (int i = 0 ; i < pds.length ; i++) {
		PropertyDescriptor pd = pds[i];
		if (pd.getName().equals(property)) {
		    return pd;
		}
	    }
	    return null;
	} catch (IntrospectionException ex) {
	    return null;
	}
    }

    protected void updateForeignKeys(JdbcBeanInterface jbean) {
	String keys[] = getForeignKeys(jbean.getClass(), bean.getClass());
	JdbcBeanSerializer ser = jbean.getSerializer();
	for (int i = 0 ; i < keys.length ; i++) { 
	    try {
		String             key    = keys[i];
		PropertyDescriptor wkeypd = getPropertyDescriptor(key);
		PropertyDescriptor rkeypd = ser.getPropertyDescriptor(key);
		Method             reader = rkeypd.getReadMethod();
		Method             writer = wkeypd.getWriteMethod();
		Object value = reader.invoke(jbean, null);
		if (value != null) {
		    Object array[] = { value };
		    writer.invoke(bean, array);
		}
	    } catch (IllegalAccessException ex) {
		ex.printStackTrace();
	    } catch (InvocationTargetException ex) {
		ex.printStackTrace();
	    }
	}
    }

    /**
     * Called by the Garbage Collector.
     */
    protected void finalize() 
	throws Throwable
    {
	// cleanup (static) cached properties
	PropertyCache.removeProperties(this.bean);
    }

    public JdbcBeanSerializer(JdbcBeanInterface bean) {
	this.bean        = bean;
	bean.addPropertyChangeListener(this);
    }

}


