/*
* Copyright 2002-2008 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.jdbc.support.lob;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Default implementation of the {@link LobHandler} interface. Invokes
* the direct accessor methods that <code>java.sql.ResultSet</code>
* and <code>java.sql.PreparedStatement</code> offer.
*
* <p>This LobHandler should work for any JDBC driver that is JDBC compliant
* in terms of the spec's suggestions regarding simple BLOB and CLOB handling.
* This does not apply to Oracle 9i, and only to a limited degree to Oracle 10g!
* As a consequence, use {@link OracleLobHandler} for accessing Oracle BLOBs/CLOBs.
*
* <p>Some JDBC drivers require values with a BLOB/CLOB target column to be
* explicitly set through the JDBC <code>setBlob</code> / <code>setClob</code>
* API: for example, PostgreSQL's driver. Switch the {@link #setWrapAsLob "wrapAsLob"}
* property to "true" when operating against such a driver.
*
* <p>On JDBC 4.0, this LobHandler also supports streaming the BLOB/CLOB content
* via the <code>setBlob</code> / <code>setClob</code> variants that take a stream
* argument directly. Consider switching the {@link #setStreamAsLob "streamAsLob"}
* property to "true" when operating against a fully compliant JDBC 4.0 driver.
*
* <p>See the {@link LobHandler} javadoc for a summary of recommendations.
*
* @author Juergen Hoeller
* @since 04.12.2003
* @see #setStreamAsLob
* @see java.sql.ResultSet#getBytes
* @see java.sql.ResultSet#getBinaryStream
* @see java.sql.ResultSet#getString
* @see java.sql.ResultSet#getAsciiStream
* @see java.sql.ResultSet#getCharacterStream
* @see java.sql.PreparedStatement#setBytes
* @see java.sql.PreparedStatement#setBinaryStream
* @see java.sql.PreparedStatement#setString
* @see java.sql.PreparedStatement#setAsciiStream
* @see java.sql.PreparedStatement#setCharacterStream
*/
public class DefaultLobHandler extends AbstractLobHandler {
protected final Log logger = LogFactory.getLog(getClass());
private boolean wrapAsLob = false;
private boolean streamAsLob = false;
/**
* Specify whether to submit a byte array / String to the JDBC driver
* wrapped in a JDBC Blob / Clob object, using the JDBC <code>setBlob</code> /
* <code>setClob</code> method with a Blob / Clob argument.
* <p>Default is "false", using the common JDBC 2.0 <code>setBinaryStream</code>
* / <code>setCharacterStream</code> method for setting the content.
* Switch this to "true" for explicit Blob / Clob wrapping against
* JDBC drivers that are known to require such wrapping (e.g. PostgreSQL's).
* <p>This setting affects byte array / String arguments as well as stream
* arguments, unless {@link #setStreamAsLob "streamAsLob"} overrides this
* handling to use JDBC 4.0's new explicit streaming support (if available).
* @see java.sql.PreparedStatement#setBlob(int, java.sql.Blob)
* @see java.sql.PreparedStatement#setClob(int, java.sql.Clob)
*/
public void setWrapAsLob(boolean wrapAsLob) {
this.wrapAsLob = wrapAsLob;
}
/**
* Specify whether to submit a binary stream / character stream to the JDBC
* driver as explicit LOB content, using the JDBC 4.0 <code>setBlob</code> /
* <code>setClob</code> method with a stream argument.
* <p>Default is "false", using the common JDBC 2.0 <code>setBinaryStream</code>
* / <code>setCharacterStream</code> method for setting the content.
* Switch this to "true" for explicit JDBC 4.0 usage, provided that your
* JDBC driver actually supports those JDBC 4.0 operations (e.g. Derby's).
* <p>This setting affects stream arguments as well as byte array / String
* arguments, requiring JDBC 4.0 support. For supporting LOB content against
* JDBC 3.0, check out the {@link #setWrapAsLob "wrapAsLob"} setting.
* @see java.sql.PreparedStatement#setBlob(int, java.io.InputStream, long)
* @see java.sql.PreparedStatement#setClob(int, java.io.Reader, long)
*/
public void setStreamAsLob(boolean streamAsLob) {
this.streamAsLob = streamAsLob;
}
public byte[] getBlobAsBytes(ResultSet rs, int columnIndex) throws SQLException {
logger.debug("Returning BLOB as bytes");
return rs.getBytes(columnIndex);
}
public InputStream getBlobAsBinaryStream(ResultSet rs, int columnIndex) throws SQLException {
logger.debug("Returning BLOB as binary stream");
return rs.getBinaryStream(columnIndex);
}
public String getClobAsString(ResultSet rs, int columnIndex) throws SQLException {
logger.debug("Returning CLOB as string");
return rs.getString(columnIndex);
}
public InputStream getClobAsAsciiStream(ResultSet rs, int columnIndex) throws SQLException {
logger.debug("Returning CLOB as ASCII stream");
return rs.getAsciiStream(columnIndex);
}
public Reader getClobAsCharacterStream(ResultSet rs, int columnIndex) throws SQLException {
logger.debug("Returning CLOB as character stream");
return rs.getCharacterStream(columnIndex);
}
public LobCreator getLobCreator() {
return new DefaultLobCreator();
}
/**
* Default LobCreator implementation as inner class.
* Can be subclassed in DefaultLobHandler extensions.
*/
protected class DefaultLobCreator implements LobCreator {
public void setBlobAsBytes(PreparedStatement ps, int paramIndex, byte[] content)
throws SQLException {
if (streamAsLob) {
if (content != null) {
ps.setBlob(paramIndex, new ByteArrayInputStream(content), content.length);
}
else {
ps.setBlob(paramIndex, (Blob) null);
}
}
else if (wrapAsLob) {
if (content != null) {
ps.setBlob(paramIndex, new PassThroughBlob(content));
}
else {
ps.setBlob(paramIndex, (Blob) null);
}
}
else {
ps.setBytes(paramIndex, content);
}
if (logger.isDebugEnabled()) {
logger.debug(content != null ? "Set bytes for BLOB with length " + content.length :
"Set BLOB to null");
}
}
public void setBlobAsBinaryStream(
PreparedStatement ps, int paramIndex, InputStream binaryStream, int contentLength)
throws SQLException {
if (streamAsLob) {
if (binaryStream != null) {
ps.setBlob(paramIndex, binaryStream, contentLength);
}
else {
ps.setBlob(paramIndex, (Blob) null);
}
}
else if (wrapAsLob) {
if (binaryStream != null) {
ps.setBlob(paramIndex, new PassThroughBlob(binaryStream, contentLength));
}
else {
ps.setBlob(paramIndex, (Blob) null);
}
}
else {
ps.setBinaryStream(paramIndex, binaryStream, contentLength);
}
if (logger.isDebugEnabled()) {
logger.debug(binaryStream != null ? "Set binary stream for BLOB with length " + contentLength :
"Set BLOB to null");
}
}
public void setClobAsString(PreparedStatement ps, int paramIndex, String content)
throws SQLException {
if (streamAsLob) {
if (content != null) {
ps.setClob(paramIndex, new StringReader(content), content.length());
}
else {
ps.setClob(paramIndex, (Clob) null);
}
}
else if (wrapAsLob) {
if (content != null) {
ps.setClob(paramIndex, new PassThroughClob(content));
}
else {
ps.setClob(paramIndex, (Clob) null);
}
}
else {
ps.setString(paramIndex, content);
}
if (logger.isDebugEnabled()) {
logger.debug(content != null ? "Set string for CLOB with length " + content.length() :
"Set CLOB to null");
}
}
public void setClobAsAsciiStream(
PreparedStatement ps, int paramIndex, InputStream asciiStream, int contentLength)
throws SQLException {
if (streamAsLob || wrapAsLob) {
if (asciiStream != null) {
try {
Reader reader = new InputStreamReader(asciiStream, "US-ASCII");
if (streamAsLob) {
ps.setClob(paramIndex, reader, contentLength);
}
else {
ps.setClob(paramIndex, new PassThroughClob(reader, contentLength));
}
}
catch (UnsupportedEncodingException ex) {
throw new SQLException("US-ASCII encoding not supported: " + ex);
}
}
else {
ps.setClob(paramIndex, (Clob) null);
}
}
else {
ps.setAsciiStream(paramIndex, asciiStream, contentLength);
}
if (logger.isDebugEnabled()) {
logger.debug(asciiStream != null ? "Set ASCII stream for CLOB with length " + contentLength :
"Set CLOB to null");
}
}
public void setClobAsCharacterStream(
PreparedStatement ps, int paramIndex, Reader characterStream, int contentLength)
throws SQLException {
if (streamAsLob) {
if (characterStream != null) {
ps.setClob(paramIndex, characterStream, contentLength);
}
else {
ps.setClob(paramIndex, (Clob) null);
}
}
else if (wrapAsLob) {
if (characterStream != null) {
ps.setClob(paramIndex, new PassThroughClob(characterStream, contentLength));
}
else {
ps.setClob(paramIndex, (Clob) null);
}
}
else {
ps.setCharacterStream(paramIndex, characterStream, contentLength);
}
if (logger.isDebugEnabled()) {
logger.debug(characterStream != null ? "Set character stream for CLOB with length " + contentLength :
"Set CLOB to null");
}
}
public void close() {
// nothing to do here
}
}
}