corner.migration.services.impl.fragment.ChangeColumnFragment.java Source code

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Here is the source code for corner.migration.services.impl.fragment.ChangeColumnFragment.java

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/* 
 * Copyright 2009 The Corner Team.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package corner.migration.services.impl.fragment;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.tapestry5.ioc.internal.util.InternalUtils;
import org.hibernate.HibernateException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.Mapping;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.mapping.Column;
import org.hibernate.mapping.Table;
import org.hibernate.tool.hbm2ddl.ColumnMetadata;
import org.hibernate.tool.hbm2ddl.TableMetadata;

import corner.migration.services.ConnectionAdapter;

/**
 * ?
 * @author <a href="jun.tsai@ganshane.net">Jun Tsai</a>
 * @version $Revision$
 * @since 0.0.2
 */
public class ChangeColumnFragment extends AbstractMigrateFragment {

    private String columnName;

    public ChangeColumnFragment(ConnectionAdapter adapter, Dialect dialect,
            SessionFactoryImplementor sessionFactory, String tableName, String columnName) {
        super(adapter, dialect, sessionFactory, tableName);
        this.columnName = columnName;

    }

    /**
     * @see corner.migration.services.MigrateFragment#generateMigrationFragments(org.hibernate.mapping.Table, org.hibernate.tool.hbm2ddl.TableMetadata)
     */
    @Override
    public List<String> generateMigrationFragments(Table table, TableMetadata tableInfo) {

        List<String> script = new ArrayList<String>();
        String alterSQL = sqlAlterStrings(table, columnName, getDialect(), getSessionFactory(), tableInfo,
                defaultCatalog, defaultSchema);
        if (InternalUtils.isNonBlank(alterSQL)) {
            script.add(alterSQL);
        } else {
            System.out.println("??????DDL?!");
        }
        return script;
    }

    // ?????DDL
    String sqlAlterStrings(Table table, String columnName, Dialect dialect, Mapping p, TableMetadata tableInfo,
            String defaultCatalog, String defaultSchema) throws HibernateException {

        Iterator iter = table.getColumnIterator();
        String alterSQL = null;

        while (iter.hasNext()) {
            Column column = (Column) iter.next();
            ColumnMetadata columnInfo = tableInfo.getColumnMetadata(column.getName());
            if (columnInfo != null && columnInfo.getName().toLowerCase().equals(columnName.toLowerCase())) {//,???
                alterSQL = this.getConnectionAdapter().changeColumnSQL(this.getQualifiedTableName(table),
                        getSQLType(column));
            }

        }
        return alterSQL;
    }

}