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public class DBTable {
protected Connection conn;
protected tableName;
public DBTable(String tableName) {
this.tableName = tableName;
this.conn = ...;
}
public void clear() {
PreparedStatement st = conn.prepareStatement("DELETE FROM "+tableName);
try {
st.executeUpdate();
}finally{
st.close();
}
}
public int getCount() {
PreparedStatement st = conn.prepareStatement("SELECT COUNT(*) FROM"+tableName);
try {ResultSet rs = st.executeQuery();
rs.next();
return rs.getInt(1);
}finally{
st.close();
}
}
}
public class ParticipantsInDB extends DBTable {
public ParticipantsInDB() {
super("participants");
}
public void addParticipant(Participant part) {
...
}
public void deleteParticipant(String participantId) {
setDeleteFlag(participantId?? true);
}
public void restoreParticipant(String participantId) {
setDeleteFlag(participantId?? false)
;
}
private void setDeleteFlag(String participantId?? boolean b) {
...
}
public void reallyDelete() {
PreparedStatement st = conn.prepareStatement("DELETE FROM "+tableName+" WHERE deleteFlag=true");
try {
st.executeUpdate();
}finally{
st.close();
}
}
public int countParticipants() {
PreparedStatement st = conn.prepareStatement("SELECT COUNT(*) FROM "+tableName+" WHERE deleteFlag=false");
try {
ResultSet rs = st.executeQuery();
rs.next();
return rs.getInt(1);
}finally{
st.close();
}
}
}