com.microsoft.sqlserver.jdbc.SQLServerClob Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of mssql-jdbc Show documentation
Show all versions of mssql-jdbc Show documentation
Microsoft JDBC Driver for SQL Server.
/*
* Microsoft JDBC Driver for SQL Server
*
* Copyright(c) Microsoft Corporation All rights reserved.
*
* This program is made available under the terms of the MIT License. See the LICENSE file in the project root for more information.
*/
package com.microsoft.sqlserver.jdbc;
import static java.nio.charset.StandardCharsets.US_ASCII;
import java.io.BufferedInputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.Serializable;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.sql.Clob;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* SQLServerClob represents a character LOB object and implements java.sql.Clob.
*/
public class SQLServerClob extends SQLServerClobBase implements Clob {
private static final long serialVersionUID = 2872035282200133865L;
// Loggers should be class static to avoid lock contention with multiple threads
private static final Logger logger = Logger.getLogger("com.microsoft.sqlserver.jdbc.internals.SQLServerClob");
/**
* Create a new CLOB
*
* @param connection
* the database connection this blob is implemented on
* @param data
* the CLOB's data
* @deprecated Use {@link SQLServerConnection#createClob()} instead.
*/
@Deprecated
public SQLServerClob(SQLServerConnection connection,
String data) {
super(connection, data, (null == connection) ? null : connection.getDatabaseCollation(), logger, null);
if (null == data)
throw new NullPointerException(SQLServerException.getErrString("R_cantSetNull"));
}
SQLServerClob(SQLServerConnection connection) {
super(connection, "", connection.getDatabaseCollation(), logger, null);
}
SQLServerClob(BaseInputStream stream,
TypeInfo typeInfo) throws SQLServerException, UnsupportedEncodingException {
super(null, stream, typeInfo.getSQLCollation(), logger, typeInfo);
}
final JDBCType getJdbcType() {
return JDBCType.CLOB;
}
}
abstract class SQLServerClobBase implements Serializable {
private static final long serialVersionUID = 8691072211054430124L;
// The value of the CLOB that this Clob object represents.
// This value is never null unless/until the free() method is called.
private String value;
private final SQLCollation sqlCollation;
private boolean isClosed = false;
private final TypeInfo typeInfo;
// Active streams which must be closed when the Clob/NClob is closed
//
// Initial size of the array is based on an assumption that a Clob/NClob object is
// typically used either for input or output, and then only once. The array size
// grows automatically if multiple streams are used.
private ArrayList activeStreams = new ArrayList<>(1);
transient SQLServerConnection con;
private final Logger logger;
final private String traceID = getClass().getName().substring(1 + getClass().getName().lastIndexOf('.')) + ":" + nextInstanceID();
final public String toString() {
return traceID;
}
static private final AtomicInteger baseID = new AtomicInteger(0); // Unique id generator for each instance (used for logging).
// Returns unique id for each instance.
private static int nextInstanceID() {
return baseID.incrementAndGet();
}
abstract JDBCType getJdbcType();
private String getDisplayClassName() {
String fullClassName = getJdbcType().className();
return fullClassName.substring(1 + fullClassName.lastIndexOf('.'));
}
/**
* Create a new CLOB from a String
*
* @param connection
* SQLServerConnection
* @param data
* the CLOB data
* @param collation
* the data collation
* @param logger
* logger information
* @param typeInfo
* the column TYPE_INFO
*/
SQLServerClobBase(SQLServerConnection connection,
Object data,
SQLCollation collation,
Logger logger,
TypeInfo typeInfo) {
this.con = connection;
if (data instanceof BaseInputStream) {
activeStreams.add((Closeable) data);
}
else {
this.value = (String) data;
}
this.sqlCollation = collation;
this.logger = logger;
this.typeInfo = typeInfo;
if (logger.isLoggable(Level.FINE)) {
String loggingInfo = (null != connection) ? connection.toString() : "null connection";
logger.fine(toString() + " created by (" + loggingInfo + ")");
}
}
/**
* Frees this Clob/NClob object and releases the resources that it holds.
*
* After free() has been called, any attempt to invoke a method other than free() will result in a SQLException being thrown. If free() is called
* multiple times, the subsequent calls to free are treated as a no-op.
*
* @throws SQLException
* when an error occurs
*/
public void free() throws SQLException {
if (!isClosed) {
// Close active streams, ignoring any errors, since nothing can be done with them after that point anyway.
if (null != activeStreams) {
for (Closeable stream : activeStreams) {
try {
stream.close();
}
catch (IOException ioException) {
logger.fine(toString() + " ignored IOException closing stream " + stream + ": " + ioException.getMessage());
}
}
activeStreams = null;
}
// Discard the value.
value = null;
isClosed = true;
}
}
/**
* Throws a SQLException if the LOB has been freed.
*/
private void checkClosed() throws SQLServerException {
if (isClosed) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_isFreed"));
SQLServerException.makeFromDriverError(con, null, form.format(new Object[] {getDisplayClassName()}), null, true);
}
}
/**
* Materialize the CLOB as an ASCII stream.
*
* @throws SQLException
* when an error occurs
* @return the data as an input stream
*/
public InputStream getAsciiStream() throws SQLException {
checkClosed();
if (null != sqlCollation && !sqlCollation.supportsAsciiConversion())
DataTypes.throwConversionError(getDisplayClassName(), "AsciiStream");
// Need to use a BufferedInputStream since the stream returned by this method is assumed to support mark/reset
InputStream getterStream;
if (null == value && !activeStreams.isEmpty()) {
InputStream inputStream = (InputStream) activeStreams.get(0);
try {
inputStream.reset();
getterStream = new BufferedInputStream(
new ReaderInputStream(new InputStreamReader(inputStream), US_ASCII, inputStream.available()));
}
catch (IOException e) {
throw new SQLServerException(e.getMessage(), null, 0, e);
}
}
else {
getStringFromStream();
getterStream = new BufferedInputStream(new ReaderInputStream(new StringReader(value), US_ASCII, value.length()));
}
return getterStream;
}
/**
* Retrieves the CLOB value designated by this Clob object as a java.io.Reader object (or as a stream of characters).
*
* @throws SQLException
* if there is an error accessing the CLOB value
* @return a java.io.Reader object containing the CLOB data
*/
public Reader getCharacterStream() throws SQLException {
checkClosed();
getStringFromStream();
Reader getterStream = new StringReader(value);
activeStreams.add(getterStream);
return getterStream;
}
/**
* Returns the Clob data as a java.io.Reader object or as a stream of characters with the specified position and length.
*
* @param pos
* A long that indicates the offset to the first character of the partial value to be retrieved.
* @param length
* A long that indicates the length in characters of the partial value to be retrieved.
* @return A Reader object that contains the Clob data.
* @throws SQLException
* when an error occurs.
*/
public Reader getCharacterStream(long pos,
long length) throws SQLException {
// Not implemented
throw new SQLFeatureNotSupportedException(SQLServerException.getErrString("R_notSupported"));
}
/**
* Retrieves 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; the value for length must be 0 or greater
* @return a String that is the specified substring in the CLOB value designated by this Clob object
* @throws SQLException
* - if there is an error accessing the CLOB value; if pos is less than 1 or length is less than 0
*/
public String getSubString(long pos,
int length) throws SQLException {
checkClosed();
getStringFromStream();
if (pos < 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {pos};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
if (length < 0) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidLength"));
Object[] msgArgs = {length};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
// Adjust pos to zero based.
pos--;
// Bound the starting position if necessary
if (pos > value.length())
pos = value.length();
// Bound the requested length to no larger than the remainder of the value beyond pos so that the
// endIndex computed for the substring call below is within bounds.
if (length > value.length() - pos)
length = (int) (value.length() - pos);
// Note String.substring uses beginIndex and endIndex (not pos and length), so calculate endIndex.
return value.substring((int) pos, (int) pos + length);
}
/**
* Retrieves the number of characters in the CLOB value designated by this Clob object.
*
* @throws SQLException
* when an error occurs
* @return length of the CLOB in characters
*/
public long length() throws SQLException {
checkClosed();
getStringFromStream();
return value.length();
}
/**
* Converts the stream to String
* @throws SQLServerException
*/
private void getStringFromStream() throws SQLServerException {
if (null == value && !activeStreams.isEmpty()) {
BaseInputStream stream = (BaseInputStream) activeStreams.get(0);
try {
stream.reset();
}
catch (IOException e) {
throw new SQLServerException(e.getMessage(), null, 0, e);
}
value = new String((stream).getBytes(), typeInfo.getCharset());
}
}
/**
* Retrieves 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 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 or -1 if it is not present; the first position is 1
* @throws SQLException
* - if there is an error accessing the CLOB value or if start is less than 1
*/
public long position(Clob searchstr,
long start) throws SQLException {
checkClosed();
getStringFromStream();
if (start < 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {start};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
if (null == searchstr)
return -1;
return position(searchstr.getSubString(1, (int) searchstr.length()), start);
}
/**
* Retrieves 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 or -1 if it is not present; the first position is 1
* @throws SQLException
* - if there is an error accessing the CLOB value or if start is less than 1
*/
public long position(String searchstr,
long start) throws SQLException {
checkClosed();
getStringFromStream();
if (start < 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {start};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
// Back compat: Handle null search string as not found rather than throw an exception.
// JDBC spec doesn't describe the behavior for a null search string.
if (null == searchstr)
return -1;
int pos = value.indexOf(searchstr, (int) (start - 1));
if (-1 != pos)
return pos + 1L;
return -1;
}
/* JDBC 3.0 methods */
/**
* Truncates the CLOB value that this Clob designates to have a length of len characters.
*
* @param len
* the length, in characters, to which the CLOB value should be truncated
* @throws SQLException
* when an error occurs
*/
public void truncate(long len) throws SQLException {
checkClosed();
getStringFromStream();
if (len < 0) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidLength"));
Object[] msgArgs = {len};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
if (len <= Integer.MAX_VALUE && value.length() > len)
value = value.substring(0, (int) len);
}
/**
* Retrieves a stream to be used to write Ascii characters to the CLOB value that this Clob object represents, starting at position pos.
*
* @param pos
* the position at which to start writing to this CLOB object
* @throws SQLException
* when an error occurs
* @return the stream to which ASCII encoded characters can be written
*/
public java.io.OutputStream setAsciiStream(long pos) throws SQLException {
checkClosed();
if (pos < 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {pos};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
return new SQLServerClobAsciiOutputStream(this, pos);
}
/**
* Retrieves a stream to be used to write a stream of Unicode characters to the CLOB value that this Clob object represents, at position pos.
*
* @param pos
* the position at which to start writing to the CLOB value
* @throws SQLException
* when an error occurs
* @return a stream to which Unicode encoded characters can be written
*/
public java.io.Writer setCharacterStream(long pos) throws SQLException {
checkClosed();
if (pos < 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {pos};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
return new SQLServerClobWriter(this, pos);
}
/**
* Writes the given Java String to the CLOB value that this Clob object designates at the position pos.
*
* @param pos
* the position at which to start writing to the CLOB
* @param s
* the string to be written to the CLOB value that this Clob designates
* @throws SQLException
* when an error occurs
* @return the number of characters written
*/
public int setString(long pos,
String s) throws SQLException {
checkClosed();
if (null == s)
SQLServerException.makeFromDriverError(con, null, SQLServerException.getErrString("R_cantSetNull"), null, true);
return setString(pos, s, 0, s.length());
}
/**
* Writes len characters of str, starting at character offset, to the CLOB value that this Clob represents. The string will overwrite the existing
* characters in the Clob object starting at the position pos. If the end of the Clob value is reached while writing the given string, then the
* length of the Clob value will be increased to accomodate the extra characters.
*
* SQL Server behavior: If the value specified for pos is greater than then length+1 of the CLOB value then a SQLException is thrown.
*
* @param pos
* - the position at which to start writing to this CLOB object; The first position is 1
* @param str
* - the string to be written to the CLOB value that this Clob object represents
* @param offset
* - the offset (0-based) into str to start reading the characters to be written
* @param len
* - the number of characters to be written
* @return the number of characters written
* @throws SQLException
* - if there is an error accessing the CLOB value or if pos is less than 1
*/
public int setString(long pos,
String str,
int offset,
int len) throws SQLException {
checkClosed();
getStringFromStream();
if (null == str)
SQLServerException.makeFromDriverError(con, null, SQLServerException.getErrString("R_cantSetNull"), null, true);
// Offset must be within incoming string str boundary.
if (offset < 0 || offset > str.length()) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidOffset"));
Object[] msgArgs = {offset};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
// len must be within incoming string str boundary.
if (len < 0 || len > str.length() - offset) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidLength"));
Object[] msgArgs = {len};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
// Note position for Clob.setString is 1 based not zero based.
// Position must be in range of existing Clob data or exactly 1 character
// past the end of data to request "append" mode.
if (pos < 1 || pos > value.length() + 1) {
MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidPositionIndex"));
Object[] msgArgs = {pos};
SQLServerException.makeFromDriverError(con, null, form.format(msgArgs), null, true);
}
// Adjust position to zero based.
pos--;
// Overwrite past end of value case.
if (len >= value.length() - pos) {
// Make sure the new value length wouldn't exceed the maximum allowed
DataTypes.getCheckedLength(con, getJdbcType(), pos + len, false);
assert pos + len <= Integer.MAX_VALUE;
// Start with the original value, up to the starting position
StringBuilder sb = new StringBuilder((int) pos + len);
sb.append(value.substring(0, (int) pos));
// Append the new value
sb.append(str.substring(offset, offset + len));
// Use the combined string as the new value
value = sb.toString();
}
// Overwrite internal to value case.
else {
// Start with the original value, up to the starting position
StringBuilder sb = new StringBuilder(value.length());
sb.append(value.substring(0, (int) pos));
// Append the new value
sb.append(str.substring(offset, offset + len));
// Append the remainder of the original value
// that was not replaced by the new value
sb.append(value.substring((int) pos + len));
// Use the combined string as the new value
value = sb.toString();
}
return len;
}
}
// SQLServerClobWriter is a simple java.io.Writer interface implementing class that
// forwards all calls to SQLServerClob.setString. This class is returned to caller by
// SQLServerClob class when setCharacterStream is called.
//
// SQLServerClobWriter starts writing at postion streamPos and continues to write
// in a forward only manner. There is no reset with java.io.Writer.
//
final class SQLServerClobWriter extends java.io.Writer {
private SQLServerClobBase parentClob = null;
private long streamPos;
SQLServerClobWriter(SQLServerClobBase parentClob,
long streamPos) {
this.parentClob = parentClob;
this.streamPos = streamPos;
}
public void write(char[] cbuf) throws IOException {
if (null == cbuf)
return;
write(new String(cbuf));
}
public void write(char[] cbuf,
int off,
int len) throws IOException {
if (null == cbuf)
return;
write(new String(cbuf, off, len));
}
public void write(int b) throws java.io.IOException {
char[] c = new char[1];
c[0] = (char) b;
write(new String(c));
}
public void write(String str,
int off,
int len) throws IOException {
checkClosed();
try {
// Call parent's setString and update position.
// setString can throw a SQLServerException, we translate
// this to an IOException here.
int charsWritten = parentClob.setString(streamPos, str, off, len);
streamPos += charsWritten;
}
catch (SQLException ex) {
throw new IOException(ex.getMessage());
}
}
public void write(String str) throws IOException {
if (null == str)
return;
write(str, 0, str.length());
}
public void flush() throws IOException {
checkClosed();
}
public void close() throws IOException {
checkClosed();
parentClob = null;
}
private void checkClosed() throws IOException {
if (null == parentClob)
throw new IOException(SQLServerException.getErrString("R_streamIsClosed"));
}
}
// SQLServerClobAsciiOutputStream is a simple java.io.OutputStream interface implementing class that
// forwards all calls to SQLServerClob.setString. This class is returned to caller by
// SQLServerClob class when setAsciiStream is called.
//
// SQLServerClobAsciiOutputStream starts writing at character postion streamPos and continues to write
// in a forward only manner. Reset/mark are not supported.
//
final class SQLServerClobAsciiOutputStream extends java.io.OutputStream {
private SQLServerClobBase parentClob = null;
private long streamPos;
SQLServerClobAsciiOutputStream(SQLServerClobBase parentClob,
long streamPos) {
this.parentClob = parentClob;
this.streamPos = streamPos;
}
public void write(byte[] b) throws IOException {
if (null == b)
return;
write(b, 0, b.length);
}
public void write(byte[] b,
int off,
int len) throws IOException {
if (null == b)
return;
try {
// Convert bytes to string using US-ASCII translation.
String s = new String(b, off, len, "US-ASCII");
// Call parent's setString and update position.
// setString can throw a SQLServerException, we translate
// this to an IOException here.
int charsWritten = parentClob.setString(streamPos, s);
streamPos += charsWritten;
}
catch (SQLException ex) {
throw new IOException(ex.getMessage());
}
}
private byte[] bSingleByte = new byte[1];
public void write(int b) throws java.io.IOException {
bSingleByte[0] = (byte) (b & 0xFF);
write(bSingleByte, 0, bSingleByte.length);
}
}