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JDBC Driver for the Firebird RDBMS
/*
* Firebird Open Source JavaEE Connector - JDBC Driver
*
* Distributable under LGPL license.
* You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* LGPL License for more details.
*
* This file was created by members of the firebird development team.
* All individual contributions remain the Copyright (C) of those
* individuals. Contributors to this file are either listed here or
* can be obtained from a source control history command.
*
* All rights reserved.
*/
package org.firebirdsql.jdbc;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.sql.Clob;
import java.sql.NClob;
import java.sql.SQLException;
/**
* The mapping in the JavaTM programming language for the SQL CLOB type. An SQL
* CLOB is a built-in type that stores a Character Large Object as a column
* value in a row of a database table. CLOBS are not currently supported by
* the Jaybird driver.
*
* The Clob interface provides methods for getting the length of an SQL CLOB
* (Character Large Object) value, for materializing a CLOB value on the client,
* and for searching for a substring or CLOB object within a CLOB value. Methods
* in the interfaces ResultSet, CallableStatement, and PreparedStatement, such
* as getClob and setClob allow a programmer to access an SQL CLOB value. In
* addition, this interface has methods for updating a CLOB value.
*
*
* This class also implements {@link NClob} so it can be used with the {@code set/get/updateNClob} methods
* transparently. It technically does not conform to the JDBC requirements for {@code NClob}.
*
*
* @author David Jencks
* @version 1.0
*/
public class FBClob implements Clob, NClob {
private final FBBlob wrappedBlob;
public FBClob(FBBlob blob) {
this.wrappedBlob = blob;
}
/**
* Returns the number of characters in the CLOB value
* designated by this Clob object.
*
* @return length of the CLOB in characters
* @exception SQLException
* if there is an error accessing the length of the
* CLOB
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public long length() throws SQLException {
throw new FBDriverNotCapableException("Cannot determine length for CLOB");
}
/**
* This operation is not currently supported Truncate this
* Clob to a given length.
*
* @param param1
* The length to truncate this Clob to
* @exception java.sql.SQLException
* this operation is not supported
*/
public void truncate(long param1) throws SQLException {
throw new FBDriverNotCapableException("Method truncate(long) is not supported");
}
/**
* Returns a copy of the specified substring in the CLOB
* value designated by this Clob object. The substring begins
* at position pos and has up to length
* consecutive characters.
*
* @param pos
* the first character of the substring to be extracted. The
* first character is at position 1.
* @param length
* the number of consecutive characters to be copied
* @return a String that is the specified substring in the
* CLOB value designated by this Clob
* object
* @exception SQLException
* if there is an error accessing the CLOB
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public String getSubString(long pos, int length) throws SQLException {
try (Reader reader = getCharacterStream()) {
long toSkip = pos - 1; // 1-based index
while (toSkip > 0) {
toSkip -= reader.skip(toSkip);
}
int n;
char[] buffer = new char[Math.min(length, 1024)];
StringBuilder sb = new StringBuilder(length);
while (length > 0 && (n = reader.read(buffer, 0, Math.min(length, buffer.length))) != -1) {
sb.append(buffer, 0, n);
length -= n;
}
return sb.toString();
} catch (IOException e) {
throw new FBSQLException(e);
}
}
/**
* Gets the CLOB value designated by this Clob
* object as a Unicode stream.
*
* @return a Unicode stream containing the CLOB data
* @exception SQLException
* if there is an error accessing the CLOB
* value
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public Reader getCharacterStream() throws SQLException {
String encoding = getWrappedBlob().getGdsHelper().getJavaEncoding();
InputStream inputStream = wrappedBlob.getBinaryStream();
if (encoding == null) {
return new InputStreamReader(inputStream);
} else {
try {
return new InputStreamReader(wrappedBlob.getBinaryStream(), encoding);
} catch (IOException ioe) {
throw new FBSQLException(ioe);
}
}
}
/**
* Gets the CLOB value designated by this Clob
* object as a stream of Ascii bytes.
*
* @return an ascii stream containing the CLOB data
* @exception SQLException
* if there is an error accessing the CLOB
* value
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public InputStream getAsciiStream() throws SQLException {
InputStream inputStream = null;
if (wrappedBlob != null) {
inputStream = wrappedBlob.getBinaryStream();
}
return inputStream;
}
/**
* Determines the character position at which the specified substring
* searchstr appears in the SQL CLOB value
* represented by this Clob object. The search begins at
* position start.
*
* @param searchstr
* the substring for which to search
* @param start
* the position at which to begin searching; the first position
* is 1
* @return the position at which the substring appears, else -1; the first
* position is 1
* @exception SQLException
* if there is an error accessing the CLOB
* value
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public long position(String searchstr, long start) throws SQLException {
throw new FBDriverNotCapableException("Method position(String, long) is not supported");
}
/**
* Determines the character position at which the specified
* Clob object searchstr appears in this
* Clob object. The search begins at position
* start.
*
* @param searchstr
* the Clob object for which to search
* @param start
* the position at which to begin searching; the first position
* is 1
* @return the position at which the Clob object appears,
* else -1; the first position is 1
* @exception SQLException
* if there is an error accessing the CLOB
* value
* @since 1.2
* @see What Is in the JDBC 2.0 API
*/
public long position(Clob searchstr, long start) throws SQLException {
throw new FBDriverNotCapableException("Method position(Clob, long) is not supported");
}
/**
* {@inheritDoc}
*
* Jaybird currently does not support this method.
*
*/
public int setString(long pos, String str) throws SQLException {
return setString(1, str, 0, str.length());
}
/**
* {@inheritDoc}
*
* Jaybird currently does not support this method.
*
*/
public int setString(long pos, String str, int offset, int len) throws SQLException {
try (Writer charStream = setCharacterStream(pos)) {
charStream.write(str, offset, len);
return len;
} catch (IOException e) {
throw new SQLException("IOException writing string to blob", e);
}
}
/**
* Set a byte stream to write the contents of this Clob.
*
* @param pos
* The position at which writing is to start.
* @return
* @exception java.sql.SQLException
*
*/
public OutputStream setAsciiStream(long pos) throws SQLException {
return wrappedBlob.setBinaryStream(pos);
}
/**
* Create a writer to add character data to this Clob.
*
* @param position
* The position at which the Writer should start writing
* @return
* @exception java.sql.SQLException
*
*/
public Writer setCharacterStream(long position) throws SQLException {
String encoding = wrappedBlob.getGdsHelper().getJavaEncoding();
// FIXME: This is wrong for multibyte charactersets; doesn't matter right now as setBinaryStream isn't implemented for position > 1
OutputStream outputStream = wrappedBlob.setBinaryStream(position);
if (encoding == null) {
return new OutputStreamWriter(outputStream);
} else {
try {
return new OutputStreamWriter(outputStream, encoding);
} catch (UnsupportedEncodingException ioe) {
throw new FBSQLException(ioe);
}
}
}
public void free() throws SQLException {
wrappedBlob.free();
}
public Reader getCharacterStream(long pos, long length) throws SQLException {
// FIXME: This is wrong for multibyte charactersets; doesn't matter right now as getBinaryStream isn't implemented
InputStream inputStream = wrappedBlob.getBinaryStream(pos, length);
String encoding = getWrappedBlob().getGdsHelper().getJavaEncoding();
if (encoding == null) {
return new InputStreamReader(inputStream);
} else {
try {
return new InputStreamReader(inputStream, encoding);
} catch (IOException ioe) {
throw new FBSQLException(ioe);
}
}
}
/**
* Copy data from a character stream into this Blob.
*
* Calling with length {@code -1} is equivalent to calling {@link #copyCharacterStream(Reader)}.
*
*
* @param characterStream the source of data to copy
* @param length The maximum number of bytes to copy, or {@code -1} to read the whole stream
*/
public void copyCharacterStream(Reader characterStream, long length) throws SQLException {
if (length == -1L) {
copyCharacterStream(characterStream);
return;
}
try (Writer writer = setCharacterStream(1)) {
int chunk;
final char[] buffer = new char[1024];
while (length > 0 && (chunk = characterStream.read(buffer)) != -1) {
writer.write(buffer, 0, chunk);
length -= chunk;
}
} catch (IOException ioe) {
throw new SQLException(ioe);
}
}
public void copyCharacterStream(Reader characterStream) throws SQLException {
try (Writer writer = setCharacterStream(1)) {
int chunk;
final char[] buffer = new char[1024];
while ((chunk = characterStream.read(buffer)) != -1) {
writer.write(buffer, 0, chunk);
}
} catch (IOException ioe) {
throw new SQLException(ioe);
}
}
/**
* Retrieves the FBBlob wrapped by this FBClob.
*
* @return FBBlob instance
* @throws SQLException
*/
public FBBlob getWrappedBlob() throws SQLException {
return wrappedBlob;
}
}