package com.avaje.ebean.config.dbplatform;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.persistence.PersistenceException;
import javax.sql.DataSource;
import com.avaje.ebean.Transaction;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A very simple Database sequence based IdGenerator.
* <p>
* One which batch requests sequence Id's would be better for performance.
* </p>
*/
public class SimpleSequenceIdGenerator implements IdGenerator {
private static final Logger logger = LoggerFactory.getLogger(SimpleSequenceIdGenerator.class);
private final String sql;
private final DataSource dataSource;
private final String seqName;
/**
* Construct given a dataSource and sql to return the next sequence value.
*/
public SimpleSequenceIdGenerator(DataSource dataSource, String sql, String seqName) {
this.dataSource = dataSource;
this.sql = sql;
this.seqName = seqName;
}
public String getName() {
return seqName;
}
public boolean isDbSequence() {
return true;
}
public void preAllocateIds(int batchSize) {
// just ignore this
}
public Object nextId(Transaction t) {
boolean useTxnConnection = t != null;
Connection c = null;
PreparedStatement pstmt = null;
ResultSet rset = null;
try {
c = useTxnConnection ? t.getConnection() : dataSource.getConnection();
pstmt = c.prepareStatement(sql);
rset = pstmt.executeQuery();
if (rset.next()) {
int val = rset.getInt(1);
return Integer.valueOf(val);
} else {
String m = "Always expecting 1 row from " + sql;
throw new PersistenceException(m);
}
} catch (SQLException e) {
throw new PersistenceException("Error getting sequence nextval", e);
} finally {
if (useTxnConnection) {
closeResources(rset, pstmt, null);
} else {
closeResources(rset, pstmt, c);
}
}
}
private void closeResources(ResultSet rset, PreparedStatement pstmt, Connection c) {
try {
if (rset != null) {
rset.close();
}
} catch (SQLException e) {
logger.error("Error closing ResultSet", e);
}
try {
if (pstmt != null) {
pstmt.close();
}
} catch (SQLException e) {
logger.error("Error closing PreparedStatement", e);
}
try {
if (c != null) {
c.close();
}
} catch (SQLException e) {
logger.error("Error closing Connection", e);
}
}
}