org.bibsonomy.database.common.util.AbstractDatabaseSchemaInformation.java Source code

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Here is the source code for org.bibsonomy.database.common.util.AbstractDatabaseSchemaInformation.java

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/**
 *
 *  BibSonomy-Database-Common - A blue social bookmark and publication sharing system.
 *
 *  Copyright (C) 2006 - 2011 Knowledge & Data Engineering Group,
 *                            University of Kassel, Germany
 *                            http://www.kde.cs.uni-kassel.de/
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser 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.bibsonomy.database.common.util;

import static org.bibsonomy.util.ValidationUtils.present;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.bibsonomy.services.database.DatabaseSchemaInformation;

import com.ibatis.sqlmap.client.SqlMapSession;
import com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate;
import com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl;
import com.ibatis.sqlmap.engine.mapping.result.ResultMap;
import com.ibatis.sqlmap.engine.mapping.result.ResultMapping;

/**
 * 
 * @author dzo
 * @version $Id: AbstractDatabaseSchemaInformation.java,v 1.1 2011-06-08 09:46:23 nosebrain Exp $
 */
public class AbstractDatabaseSchemaInformation implements DatabaseSchemaInformation {
    private static final Log log = LogFactory.getLog(AbstractDatabaseSchemaInformation.class);

    protected static final String COLUMN_SIZE = "COLUMN_SIZE";

    private final Map<Class<?>, Map<String, Integer>> fieldLength = new HashMap<Class<?>, Map<String, Integer>>();

    /**
     * returns meta informations of the database
     * 
     * @param <R>
     * @param resultClass
     * @param tableNamePattern
     * @param columnNamePattern
     * @param columnLabel
     * 
     * @return the schema information of the column of the table
     */
    @SuppressWarnings("unchecked")
    protected static <R> R getSchemaInformation(/* only used for the cast */final Class<R> resultClass,
            final String tableNamePattern, final String columnNamePattern, final String columnLabel,
            final SqlMapSession sqlMapSession) {
        final DataSource dataSource = sqlMapSession.getDataSource();

        Connection connection = null;

        try {
            connection = dataSource.getConnection();
            final DatabaseMetaData metaData = connection.getMetaData();
            final ResultSet columns = metaData.getColumns(null, null, tableNamePattern, columnNamePattern);
            while (columns.next()) {
                return (R) columns.getObject(columnLabel);
            }
        } catch (final SQLException ex) {
            log.warn("can't get schema informations for column '" + columnNamePattern + "' of table '"
                    + tableNamePattern + "'", ex);
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (final SQLException ex) {
                    log.warn("can't close connection", ex);
                }
            }
        }

        return null;
    }

    protected void insertMaxFieldLengths(final String mappingId, final String tableName,
            final SqlMapSession sqlMap) {
        final Map<String, Integer> maxLength = new HashMap<String, Integer>();

        if (sqlMap instanceof SqlMapSessionImpl) {
            final SqlMapSessionImpl impl = (SqlMapSessionImpl) sqlMap;
            final SqlMapExecutorDelegate delegate = impl.getDelegate();
            final ResultMap resultMap = delegate.getResultMap(mappingId);
            final ResultMapping[] resultMappings = resultMap.getResultMappings();

            final Class<?> resultClass = resultMap.getResultClass();

            for (final ResultMapping mapping : resultMappings) {
                final String propertyName = mapping.getPropertyName();
                final String columnName = mapping.getColumnName();

                final Integer columnMax = getSchemaInformation(Integer.class, tableName, columnName, COLUMN_SIZE,
                        sqlMap);
                maxLength.put(propertyName, columnMax);
            }

            this.fieldLength.put(resultClass, maxLength);
        } else {
            log.warn("SqlMapSession isn't an instance of SqlMapSessionImpl. Can't get iBatis Mapping.");
        }
    }

    @Override
    public int getMaxColumnLengthForProperty(final Class<?> resourceClass, final String property) {
        final Map<String, Integer> properties = this.fieldLength.get(resourceClass);

        if (present(properties)) {
            final Integer maxLength = properties.get(property);
            return present(maxLength) ? maxLength : -1;
        }

        final Class<?> superclass = resourceClass.getSuperclass();
        if (!Object.class.equals(superclass)) {
            return this.getMaxColumnLengthForProperty(superclass, property);
        }

        return -1;
    }

}