org.apache.juneau.dto.ResultSetList Maven / Gradle / Ivy
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// * http://www.apache.org/licenses/LICENSE-2.0 *
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package org.apache.juneau.dto;
import static org.apache.juneau.internal.IOUtils.*;
import java.sql.*;
import java.util.*;
import org.apache.juneau.internal.*;
/**
* Transforms an SQL {@link ResultSet ResultSet} into a list of maps.
* <
* p>
* Loads the entire result set into an in-memory data structure, and then closes the result set object.
*/
public final class ResultSetList extends LinkedList> {
private static final long serialVersionUID = 1L;
/**
* Constructor.
*
* @param rs The result set to load into this DTO.
* @param pos The start position (zero-indexed).
* @param limit The maximum number of rows to retrieve.
* @param includeRowNums Make the first column be the row number.
* @throws SQLException Database error.
*/
public ResultSetList(ResultSet rs, int pos, int limit, boolean includeRowNums) throws SQLException {
try {
int rowNum = pos;
// Get the column names.
ResultSetMetaData rsmd = rs.getMetaData();
int offset = (includeRowNums ? 1 : 0);
int cc = rsmd.getColumnCount();
String[] columns = new String[cc + offset];
if (includeRowNums)
columns[0] = "ROW";
int[] colTypes = new int[cc];
for (int i = 0; i < cc; i++) {
columns[i+offset] = rsmd.getColumnName(i+1);
colTypes[i] = rsmd.getColumnType(i+1);
}
while (--pos > 0 && rs.next()) {}
// Get the rows.
while (limit-- > 0 && rs.next()) {
Object[] row = new Object[cc + offset];
if (includeRowNums)
row[0] = rowNum++;
for (int i = 0; i < cc; i++) {
Object o = readEntry(rs, i+1, colTypes[i]);
row[i+offset] = o;
}
add(new SimpleMap(columns, row));
}
} finally {
rs.close();
}
}
/**
* Reads the specified column from the current row in the result set.
*
*
* Subclasses can override this method to handle specific data types in special ways.
*
* @param rs The result set to read from.
* @param col The column number (indexed by 1).
* @param dataType The {@link Types type} of the entry.
* @return The entry as an Object.
*/
protected static Object readEntry(ResultSet rs, int col, int dataType) {
try {
switch (dataType) {
case Types.BLOB:
Blob b = rs.getBlob(col);
return "blob["+b.length()+"]";
case Types.CLOB:
Clob c = rs.getClob(col);
return "clob["+c.length()+"]";
case Types.LONGVARBINARY:
return "longvarbinary["+count(rs.getBinaryStream(col))+"]";
case Types.LONGVARCHAR:
return "longvarchar["+count(rs.getAsciiStream(col))+"]";
case Types.LONGNVARCHAR:
return "longnvarchar["+count(rs.getCharacterStream(col))+"]";
case Types.TIMESTAMP:
return rs.getTimestamp(col); // Oracle returns com.oracle.TIMESTAMP objects from getObject() which isn't a Timestamp.
default:
return rs.getObject(col);
}
} catch (Exception e) {
return e.getLocalizedMessage();
}
}
}