/*
* EasyDriver is a library that let a programmer build queries easier
* than using plain JDBC.
* Copyright (C) 2011 Paolo Proni
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.byteliberi.easydriver;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.byteliberi.easydriver.expressions.Equals;
import org.byteliberi.easydriver.impl.ExecutableQuery;
import org.byteliberi.easydriver.impl.FilteredQuery;
import org.byteliberi.easydriver.impl.FilteredQueryAPI;
/**
* This query modifies the values of the fields of a table in the database.
*
* @author Paolo Proni
* @version 1.0
* @since 1.0
*/
public class UpdateQuery extends ExecutableQuery implements FilteredQueryAPI {
private final static String UPDATE = "UPDATE ";
private final static String SET = " SET ";
private final static Level LOG_LEVEL = Level.FINE;
protected ExpressionAPI[] expressions = null;
/**
* This class contains some reusable code for the queries that have
* a <code>WHERE</code> clause.
*/
private FilteredQuery filteredQuery = null;
/**
* Creates a new instance of this class.
* @param updateFields Fields of the passed table, where the values are updated by this query.
* @param table
*/
public UpdateQuery(final TableField<?>[] updateFields, final DBTable<?> table) {
this.table = table;
final int fieldLen = updateFields.length;
this.expressions = new ExpressionAPI[fieldLen];
for (int i = 0; i < fieldLen; i++)
this.expressions[i] = new Equals( updateFields[i], false );
}
public UpdateQuery(final ExpressionAPI[] expressions, final DBTable<?> table) {
this.expressions = expressions;
this.table = table;
}
@Override
protected String createQueryString() {
final StringBuilder sbQuery = new StringBuilder(100);
sbQuery.append(UPDATE).append(this.table.getCompleteName()).append(SET);
for (ExpressionAPI expression : this.expressions)
sbQuery.append(expression.createString()).append(',');
sbQuery.deleteCharAt(sbQuery.length() - 1);
final ExpressionAPI[] whereClause = getFilteredQuery().getExpression();
if (whereClause != null) {
sbQuery.append(WHERE);
for (ExpressionAPI expr : whereClause)
sbQuery.append(expr.createString());
}
final String query = sbQuery.toString();
final Logger logger = Logger.getLogger(InsertQuery.class.getName());
logger.log(LOG_LEVEL, query);
return query;
}
/**
* This method get the where part manager of the query.
* @return This class contains some reusable code for the queries that have
* a <code>WHERE</code> clause.
*/
private FilteredQuery getFilteredQuery() {
// Lazy constructor
if (this.filteredQuery == null)
this.filteredQuery = new FilteredQuery();
return this.filteredQuery;
}
@Override
public void setWhere(TableField<?> field) {
getFilteredQuery().setWhere(field);
}
@Override
public void setWhere(ExpressionAPI exp) {
getFilteredQuery().setWhere(exp);
}
@Override
public void setWhere(ExpressionAPI[] exp) {
getFilteredQuery().setWhere(exp);
}
}