org.tentackle.sql.metadata.IndexColumnMetaData Maven / Gradle / Ivy
/*
* Tentackle - https://tentackle.org.
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.tentackle.sql.metadata;
import org.tentackle.common.StringHelper;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* Meta data for a column of an index.
*
* @author harald
*/
public class IndexColumnMetaData implements Comparable {
private final IndexMetaData indexMetaData; // index column belongs to
private String columnName; // column columnName
private String functionName; // optional function name
private boolean descending; // true = DESC, false = ASC
private int position; // ordinal position within index
/**
* Creates an index column.
*
* @param indexMetaData the index column belongs to
*/
public IndexColumnMetaData(IndexMetaData indexMetaData) {
this.indexMetaData = indexMetaData;
}
/**
* Sets up the index column from the database meta data result.
*
* @param resultSet the column result set
* @throws SQLException the processing the result set failed
*/
public void setupIndexColumnFromMetaData(ResultSet resultSet) throws SQLException {
columnName = StringHelper.toLower(resultSet.getString("COLUMN_NAME"));
// check if functional index
int ndx1 = columnName.indexOf('(');
if (ndx1 >= 0) {
int ndx2 = columnName.lastIndexOf(')');
if (ndx2 > ndx1) {
functionName = columnName.substring(0, ndx1).trim().toUpperCase();
columnName = columnName.substring(ndx1 + 1, ndx2).trim().toLowerCase();
}
}
String ascDesc = resultSet.getString("ASC_OR_DESC");
descending = ascDesc != null && ascDesc.startsWith("D");
position = resultSet.getShort("ORDINAL_POSITION");
validate();
}
/**
* Gets the index.
*
* @return index column belongs to
*/
public IndexMetaData getIndexMetaData() {
return indexMetaData;
}
/**
* Returns ascending or descending order.
*
* @return true if descending
*/
public boolean isDescending() {
return descending;
}
/**
* Gets the column columnName.
*
* @return the index column's columnName in lowercase
*/
public String getColumnName() {
return columnName;
}
/**
* Gets the optional function name.
*
* @return the function in uppercase, null if none
*/
public String getFunctionName() {
return functionName;
}
/**
* Gets the ordinal position within the index.
*
* @return the position
*/
public int getPosition() {
return position;
}
@Override
public int compareTo(IndexColumnMetaData o) {
return position - o.position;
}
/**
* Validates and postprocesses the index column data.
*/
public void validate() {
// nothing to do
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder(columnName);
if (descending) {
buf.append(" DESC");
}
return buf.toString();
}
}