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Java JDBC 4.0 (JRE 6+) driver for PostgreSQL database
/*-------------------------------------------------------------------------
*
* Copyright (c) 2009-2014, PostgreSQL Global Development Group
*
*
*-------------------------------------------------------------------------
*/
/**
* Bulk data copy for PostgreSQL
*/
package org.postgresql.copy;
import java.io.IOException;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.Reader;
import java.io.Writer;
import java.sql.SQLException;
import org.postgresql.core.Encoding;
import org.postgresql.core.QueryExecutor;
import org.postgresql.core.BaseConnection;
import org.postgresql.util.GT;
import org.postgresql.util.PSQLException;
import org.postgresql.util.PSQLState;
/**
* API for PostgreSQL COPY bulk data transfer
*/
public class CopyManager {
// I don't know what the best buffer size is, so we let people specify it if
// they want, and if they don't know, we don't make them guess, so that if we
// do figure it out we can just set it here and they reap the rewards.
// Note that this is currently being used for both a number of bytes and a number
// of characters.
final static int DEFAULT_BUFFER_SIZE = 65536;
private final Encoding encoding;
private final QueryExecutor queryExecutor;
private final BaseConnection connection;
public CopyManager(BaseConnection connection) throws SQLException {
this.encoding = connection.getEncoding();
this.queryExecutor = connection.getQueryExecutor();
this.connection = connection;
}
public CopyIn copyIn(String sql) throws SQLException {
CopyOperation op = null;
try {
op = queryExecutor.startCopy(sql, connection.getAutoCommit());
return (CopyIn) op;
} catch(ClassCastException cce) {
op.cancelCopy();
throw new PSQLException(GT.tr("Requested CopyIn but got {0}", op.getClass().getName()), PSQLState.WRONG_OBJECT_TYPE, cce);
}
}
public CopyOut copyOut(String sql) throws SQLException {
CopyOperation op = null;
try {
op = queryExecutor.startCopy(sql, connection.getAutoCommit());
return (CopyOut) op;
} catch(ClassCastException cce) {
op.cancelCopy();
throw new PSQLException(GT.tr("Requested CopyOut but got {0}", op.getClass().getName()), PSQLState.WRONG_OBJECT_TYPE, cce);
}
}
/**
* Pass results of a COPY TO STDOUT query from database into a Writer.
* @param sql COPY TO STDOUT statement
* @param to the stream to write the results to (row by row)
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage errors
* @throws IOException upon writer or database connection failure
*/
public long copyOut(final String sql, Writer to) throws SQLException, IOException {
byte[] buf;
CopyOut cp = copyOut(sql);
try {
while ( (buf = cp.readFromCopy()) != null ) {
to.write(encoding.decode(buf));
}
return cp.getHandledRowCount();
}
catch ( IOException ioEX) {
// if not handled this way the close call will hang, at least in 8.2
if(cp.isActive())
cp.cancelCopy();
try { // read until excausted or operation cancelled SQLException
while( (buf = cp.readFromCopy()) != null ) {}
}
catch ( SQLException sqlEx ) {} // typically after several kB
throw ioEX;
}
finally { // see to it that we do not leave the connection locked
if(cp.isActive())
cp.cancelCopy();
}
}
/**
* Pass results of a COPY TO STDOUT query from database into an OutputStream.
* @param sql COPY TO STDOUT statement
* @param to the stream to write the results to (row by row)
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage errors
* @throws IOException upon output stream or database connection failure
*/
public long copyOut(final String sql, OutputStream to) throws SQLException, IOException {
byte[] buf;
CopyOut cp = copyOut(sql);
try {
while( (buf = cp.readFromCopy()) != null ) {
to.write(buf);
}
return cp.getHandledRowCount();
}
catch ( IOException ioEX) {
// if not handled this way the close call will hang, at least in 8.2
if(cp.isActive())
cp.cancelCopy();
try { // read until excausted or operation cancelled SQLException
while( (buf = cp.readFromCopy()) != null ) {}
}
catch ( SQLException sqlEx ) {} // typically after several kB
throw ioEX ;
}
finally { // see to it that we do not leave the connection locked
if(cp.isActive())
cp.cancelCopy();
}
}
/**
* Use COPY FROM STDIN for very fast copying from a Reader into a database table.
* @param sql COPY FROM STDIN statement
* @param from a CSV file or such
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage issues
* @throws IOException upon reader or database connection failure
*/
public long copyIn(final String sql, Reader from) throws SQLException, IOException {
return copyIn(sql, from, DEFAULT_BUFFER_SIZE);
}
/**
* Use COPY FROM STDIN for very fast copying from a Reader into a database table.
* @param sql COPY FROM STDIN statement
* @param from a CSV file or such
* @param bufferSize number of characters to buffer and push over network to server at once
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage issues
* @throws IOException upon reader or database connection failure
*/
public long copyIn(final String sql, Reader from, int bufferSize) throws SQLException, IOException {
char[] cbuf = new char[bufferSize];
int len;
CopyIn cp = copyIn(sql);
try {
while ( (len = from.read(cbuf)) >= 0)
{
if (len > 0)
{
byte[] buf = encoding.encode(new String(cbuf, 0, len));
cp.writeToCopy(buf, 0, buf.length);
}
}
return cp.endCopy();
} finally { // see to it that we do not leave the connection locked
if(cp.isActive())
cp.cancelCopy();
}
}
/**
* Use COPY FROM STDIN for very fast copying from an InputStream into a database table.
* @param sql COPY FROM STDIN statement
* @param from a CSV file or such
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage issues
* @throws IOException upon input stream or database connection failure
*/
public long copyIn(final String sql, InputStream from) throws SQLException, IOException {
return copyIn(sql, from, DEFAULT_BUFFER_SIZE);
}
/**
* Use COPY FROM STDIN for very fast copying from an InputStream into a database table.
* @param sql COPY FROM STDIN statement
* @param from a CSV file or such
* @param bufferSize number of bytes to buffer and push over network to server at once
* @return number of rows updated for server 8.2 or newer; -1 for older
* @throws SQLException on database usage issues
* @throws IOException upon input stream or database connection failure
*/
public long copyIn(final String sql, InputStream from, int bufferSize) throws SQLException, IOException {
byte[] buf = new byte[bufferSize];
int len;
CopyIn cp = copyIn(sql);
try {
while( (len = from.read(buf)) >= 0 )
{
if (len > 0)
{
cp.writeToCopy(buf, 0, len);
}
}
return cp.endCopy();
} finally { // see to it that we do not leave the connection locked
if(cp.isActive())
cp.cancelCopy();
}
}
}