org.hsqldb.jdbc.JDBCBlob Maven / Gradle / Ivy
/* Copyright (c) 2001-2014, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb.jdbc;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.SQLException;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.KMPSearchAlgorithm;
import org.hsqldb.lib.java.JavaSystem;
// boucherb@users 2004-04-xx - patch 1.7.2 - position and truncate methods
// implemented; minor changes for moderate thread
// safety and optimal performance
// boucherb@users 2004-04-xx - doc 1.7.2 - javadocs updated; methods put in
// correct (historical, interface declared) order
// boucherb@users 2005-12-07 - patch 1.8.0.x - initial JDBC 4.0 support work
// boucherb@users 2006-05-22 - doc 1.9.0 - full synch up to Mustang Build 84
// - patch 1.9.0 - setBinaryStream improvement
// patch 1.9.0
// - fixed invalid reference to new BinaryStream(...) in getBinaryStream
//
// patch 1.9.0 - full synch up to Mustang b90
// - better bounds checking
// - added support for clients to decide whether getBinaryStream
// uses copy of internal byte buffer
/**
* The representation (mapping) in
* the JavaTM programming
* language of an SQL
* BLOB value. An SQL BLOB is a built-in type
* that stores a Binary Large Object as a column value in a row of
* a database table. By default drivers implement Blob using
* an SQL locator(BLOB), which means that a
* Blob object contains a logical pointer to the
* SQL BLOB data rather than the data itself.
* A Blob object is valid for the duration of the
* transaction in which is was created.
*
* Methods in the interfaces {@link java.sql.ResultSet},
* {@link java.sql.CallableStatement}, and {@link java.sql.PreparedStatement}, such as
* getBlob and setBlob allow a programmer to
* access an SQL BLOB value.
* The Blob interface provides methods for getting the
* length of an SQL BLOB (Binary Large Object) value,
* for materializing a BLOB value on the client, and for
* determining the position of a pattern of bytes within a
* BLOB value. In addition, this interface has methods for updating
* a BLOB value.
*
* All methods on the Blob interface must be fully implemented if the
* JDBC driver supports the data type.
*
*
*
* HSQLDB-Specific Information:
*
* Previous to 2.0, the HSQLDB driver did not implement Blob using an SQL
* locator(BLOB). That is, an HSQLDB Blob object did not contain a logical
* pointer to SQL BLOB data; rather it directly contained a representation of
* the data (a byte array). As a result, an HSQLDB Blob object was itself
* valid beyond the duration of the transaction in which is was created,
* although it did not necessarily represent a corresponding value
* on the database. Also, the interface methods for updating a BLOB value
* were unsupported, with the exception of the truncate method,
* in that it could be used to truncate the local value.
*
* Starting with 2.0, the HSQLDB driver fully supports both local and remote
* SQL BLOB data implementations, meaning that an HSQLDB Blob object may
* contain a logical pointer to remote SQL BLOB data (see {@link JDBCBlobClient
* JDBCBlobClient}) or it may directly contain a local representation of the
* data (as implemented in this class). In particular, when the product is built
* under JDK 1.6+ and the Blob instance is constructed as a result of calling
* JDBCConnection.createBlob(), then the resulting Blob instance is initially
* disconnected (is not bound to the transaction scope of the vending Connection
* object), the data is contained directly and all interface methods for
* updating the BLOB value are supported for local use until the first
* invocation of free(); otherwise, an HSQLDB Blob's implementation is
* determined at runtime by the driver, it is typically not valid beyond the
* duration of the transaction in which is was created, and there no
* standard way to query whether it represents a local or remote
* value.
*
*
*
*
* @author james house [email protected]
* @author boucherb@users
* @version 2.3.0
* @since JDK 1.2, HSQLDB 1.7.2
* @revised JDK 1.6, HSQLDB 2.0
*/
public class JDBCBlob implements Blob {
/**
* Returns the number of bytes in the BLOB value
* designated by this Blob object.
* @return length of the BLOB in bytes
* @exception SQLException if there is an error accessing the
* length of the BLOB
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.2, HSQLDB 1.7.2
*/
public long length() throws SQLException {
return getData().length;
}
/**
* Retrieves all or part of the BLOB
* value that this Blob object represents, as an array of
* bytes. This byte array contains up to length
* consecutive bytes starting at position pos.
*
*
*
* HSQLDB-Specific Information:
*
* The official specification above is ambiguous in that it does not
* precisely indicate the policy to be observed when
* pos > this.length() - length. One policy would be to retrieve the
* octets from pos to this.length(). Another would be to throw an
* exception. HSQLDB observes the second policy.
*
*
* @param pos the ordinal position of the first byte in the
* BLOB value to be extracted; the first byte is at
* position 1
* @param length the number of consecutive bytes to be copied; JDBC 4.1[the value
* for length must be 0 or greater]
* @return a byte array containing up to length
* consecutive bytes from the BLOB value designated
* by this Blob object, starting with the
* byte at position pos
* @exception SQLException if there is an error accessing the
* BLOB value; if pos is less than 1 or length is
* less than 0
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @see #setBytes
* @since JDK 1.2, HSQLDB 1.7.2
*/
public byte[] getBytes(long pos, final int length) throws SQLException {
final byte[] data = getData();
final int dlen = data.length;
if (pos < MIN_POS || pos > MIN_POS + dlen) {
throw JDBCUtil.outOfRangeArgument("pos: " + pos);
}
pos--;
if (length < 0 || length > dlen - pos) {
throw JDBCUtil.outOfRangeArgument("length: " + length);
}
final byte[] result = new byte[length];
System.arraycopy(data, (int) pos, result, 0, length);
return result;
}
/**
* Retrieves the BLOB value designated by this
* Blob instance as a stream.
*
* @return a stream containing the BLOB data
* @exception SQLException if there is an error accessing the
* BLOB value
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @see #setBinaryStream
* @since JDK 1.2, HSQLDB 1.7.2
*/
public InputStream getBinaryStream() throws SQLException {
return new ByteArrayInputStream(getData());
}
/**
* Retrieves the byte position at which the specified byte array
* pattern begins within the BLOB
* value that this Blob object represents. The
* search for pattern begins at position
* start.
*
* @param pattern the byte array for which to search
* @param start the position at which to begin searching; the
* first position is 1
* @return the position at which the pattern appears, else -1
* @exception SQLException if there is an error accessing the
* BLOB or if start is less than 1
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.2, HSQLDB 1.7.2
*/
public long position(final byte[] pattern,
final long start) throws SQLException {
final byte[] data = getData();
final int dlen = data.length;
if (start < MIN_POS) {
throw JDBCUtil.outOfRangeArgument("start: " + start);
} else if (start > dlen || pattern == null) {
return -1L;
}
// by now, we know start <= Integer.MAX_VALUE;
final int startIndex = (int) start - 1;
final int plen = pattern.length;
if (plen == 0 || startIndex > dlen - plen) {
return -1L;
}
final int result = KMPSearchAlgorithm.search(data, pattern,
KMPSearchAlgorithm.computeTable(pattern), startIndex);
return (result == -1) ? -1
: result + 1;
}
/**
* Retrieves the byte position in the BLOB value
* designated by this Blob object at which
* pattern begins. The search begins at position
* start.
*
* @param pattern the Blob object designating
* the BLOB value for which to search
* @param start the position in the BLOB value
* at which to begin searching; the first position is 1
* @return the position at which the pattern begins, else -1
* @exception SQLException if there is an error accessing the
* BLOB value or if start is less than 1
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.2, HSQLDB 1.7.2
*/
public long position(final Blob pattern, long start) throws SQLException {
final byte[] data = getData();
final int dlen = data.length;
if (start < MIN_POS) {
throw JDBCUtil.outOfRangeArgument("start: " + start);
} else if (start > dlen || pattern == null) {
return -1L;
}
// by now, we know start <= Integer.MAX_VALUE;
final int startIndex = (int) start - 1;
final long plen = pattern.length();
if (plen == 0 || startIndex > ((long) dlen) - plen) {
return -1L;
}
// by now, we know plen <= Integer.MAX_VALUE
final int iplen = (int) plen;
byte[] bytePattern;
if (pattern instanceof JDBCBlob) {
bytePattern = ((JDBCBlob) pattern).data();
} else {
bytePattern = pattern.getBytes(1L, iplen);
}
final int result = KMPSearchAlgorithm.search(data, bytePattern,
KMPSearchAlgorithm.computeTable(bytePattern), startIndex);
return (result == -1) ? -1
: result + 1;
}
// -------------------------- JDBC 3.0 -----------------------------------
/**
* Writes the given array of bytes to the BLOB value that
* this Blob object represents, starting at position
* pos, and returns the number of bytes written.
* The array of bytes will overwrite the existing bytes
* in the Blob object starting at the position
* pos. If the end of the Blob value is reached
* while writing the array of bytes, then the length of the Blob
* value will be increased to accommodate the extra bytes.
*
* Note: If the value specified for pos
* is greater then the length+1 of the BLOB value then the
* behavior is undefined. Some JDBC drivers may throw a
* SQLException while other drivers may support this
* operation.
*
*
*
* HSQLDB-Specific Information:
*
* Starting with HSQLDB 2.0 this feature is supported.
*
* When built under JDK 1.6+ and the Blob instance is constructed as a
* result of calling JDBCConnection.createBlob(), this operation affects
* only the client-side value; it has no effect upon a value stored in a
* database because JDBCConnection.createBlob() constructs disconnected,
* initially empty Blob instances. To propagate the Blob value to a database
* in this case, it is required to supply the Blob instance to an updating
* or inserting setXXX method of a Prepared or Callable Statement, or to
* supply the Blob instance to an updateXXX method of an updateable
* ResultSet.
*
* Implementation Notes:
*
* Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields
* and is effectively thread safe, but still uses local variable
* snapshot isolation.
*
* As such, the synchronization policy still does not strictly enforce
* serialized read/write access to the underlying data
*
* So, if an application may perform concurrent JDBCBlob modifications and
* the integrity of the application depends on total order Blob modification
* semantics, then such operations should be synchronized on an appropriate
* monitor.
*
*
*
*
* @param pos the position in the BLOB object at which
* to start writing; the first position is 1
* @param bytes the array of bytes to be written to the BLOB
* value that this Blob object represents
* @return the number of bytes written
* @exception SQLException if there is an error accessing the
* BLOB value or if pos is less than 1
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @see #getBytes
* @since JDK 1.4, HSQLDB 1.7.2
* @revised JDK 1.6, HSQLDB 2.0
*/
public int setBytes(long pos, byte[] bytes) throws SQLException {
if (bytes == null) {
throw JDBCUtil.nullArgument("bytes");
}
return setBytes(pos, bytes, 0, bytes.length);
}
/**
* Writes all or part of the given byte array to the
* BLOB value that this Blob object represents
* and returns the number of bytes written.
* Writing starts at position pos in the BLOB
* value; len bytes from the given byte array are written.
* The array of bytes will overwrite the existing bytes
* in the Blob object starting at the position
* pos. If the end of the Blob value is reached
* while writing the array of bytes, then the length of the Blob
* value will be increased to accommodate the extra bytes.
*
* Note: If the value specified for pos
* is greater then the length+1 of the BLOB value then the
* behavior is undefined. Some JDBC drivers may throw a
* SQLException while other drivers may support this
* operation.
*
*
*
* HSQLDB-Specific Information:
*
* Starting with HSQLDB 2.0 this feature is supported.
*
* When built under JDK 1.6+ and the Blob instance is constructed as a
* result of calling JDBCConnection.createBlob(), this operation affects
* only the client-side value; it has no effect upon a value stored in a
* database because JDBCConnection.createBlob() constructs disconnected,
* initially empty Blob instances. To propagate the Blob value to a database
* in this case, it is required to supply the Blob instance to an updating
* or inserting setXXX method of a Prepared or Callable Statement, or to
* supply the Blob instance to an updateXXX method of an updateable
* ResultSet.
*
* Implementation Notes:
*
* If the value specified for pos
* is greater than the length of the BLOB value, then
* the BLOB value is extended in length to accept the
* written octets and the undefined region up to pos is
* filled with (byte)0.
*
* Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields
* and is effectively thread safe, but still uses local variable
* snapshot isolation.
*
* As such, the synchronization policy still does not strictly enforce
* serialized read/write access to the underlying data
*
* So, if an application may perform concurrent JDBCBlob modifications and
* the integrity of the application depends on total order Blob modification
* semantics, then such operations should be synchronized on an appropriate
* monitor.
*
*
*
*
* @param pos the position in the BLOB object at which
* to start writing; the first position is 1
* @param bytes the array of bytes to be written to this BLOB
* object
* @param offset the offset into the array bytes at which
* to start reading the bytes to be set
* @param len the number of bytes to be written to the BLOB
* value from the array of bytes bytes
* @return the number of bytes written
* @exception SQLException if there is an error accessing the
* BLOB value or if pos is less than 1
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @see #getBytes
* @since JDK 1.4, HSQLDB 1.7.2
* @revised JDK 1.6, HSQLDB 2.0
*/
public int setBytes(long pos, byte[] bytes, int offset,
int len) throws SQLException {
if (!m_createdByConnection) {
/** @todo - better error message */
throw JDBCUtil.notSupported();
}
if (bytes == null) {
throw JDBCUtil.nullArgument("bytes");
}
if (offset < 0 || offset > bytes.length) {
throw JDBCUtil.outOfRangeArgument("offset: " + offset);
}
if (len > bytes.length - offset) {
throw JDBCUtil.outOfRangeArgument("len: " + len);
}
if (pos < MIN_POS || pos > 1L + (Integer.MAX_VALUE - len)) {
throw JDBCUtil.outOfRangeArgument("pos: " + pos);
}
pos--;
byte[] data = getData();
final int dlen = data.length;
if ((pos + len) > dlen) {
byte[] temp = new byte[(int) pos + len];
System.arraycopy(data, 0, temp, 0, dlen);
data = temp;
temp = null;
}
System.arraycopy(bytes, offset, data, (int) pos, len);
// paranoia, in case somone free'd us during the array copies.
checkClosed();
setData(data);
return len;
}
/**
* Retrieves a stream that can be used to write to the BLOB
* value that this Blob object represents. The stream begins
* at position pos.
* The bytes written to the stream will overwrite the existing bytes
* in the Blob object starting at the position
* pos. If the end of the Blob value is reached
* while writing to the stream, then the length of the Blob
* value will be increased to accommodate the extra bytes.
*
* Note: If the value specified for pos
* is greater then the length+1 of the BLOB value then the
* behavior is undefined. Some JDBC drivers may throw a
* SQLException while other drivers may support this
* operation.
*
*
*
* HSQLDB-Specific Information:
*
* Starting with HSQLDB 2.0 this feature is supported.
*
* When built under JDK 1.6+ and the Blob instance is constructed as a
* result of calling JDBCConnection.createBlob(), this operation affects
* only the client-side value; it has no effect upon a value stored in a
* database because JDBCConnection.createBlob() constructs disconnected,
* initially empty Blob instances. To propagate the Blob value to a database
* in this case, it is required to supply the Blob instance to an updating
* or inserting setXXX method of a Prepared or Callable Statement, or to
* supply the Blob instance to an updateXXX method of an updateable
* ResultSet.
*
* Implementation Notes:
*
* The data written to the stream does not appear in this
* Blob until the stream is closed
*
* When the stream is closed, if the value specified for pos
* is greater than the length of the BLOB value, then
* the BLOB value is extended in length to accept the
* written octets and the undefined region up to pos is
* filled with (byte)0.
*
* Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields
* and is effectively thread safe, but still uses local variable
* snapshot isolation.
*
* As such, the synchronization policy still does not strictly enforce
* serialized read/write access to the underlying data
*
* So, if an application may perform concurrent JDBCBlob modifications and
* the integrity of the application depends on total order Blob modification
* semantics, then such operations should be synchronized on an appropriate
* monitor.
*
*
*
*
* @param pos the position in the BLOB value at which
* to start writing; the first position is 1
* @return a java.io.OutputStream object to which data can
* be written
* @exception SQLException if there is an error accessing the
* BLOB value or if pos is less than 1
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @see #getBinaryStream
* @since JDK 1.4, HSQLDB 1.7.2
* @revised JDK 1.6, HSQLDB 2.0
*/
public OutputStream setBinaryStream(final long pos) throws SQLException {
if (!m_createdByConnection) {
/** @todo - Better error message */
throw JDBCUtil.notSupported();
}
if (pos < MIN_POS || pos > MAX_POS) {
throw JDBCUtil.outOfRangeArgument("pos: " + pos);
}
checkClosed();
return new java.io.ByteArrayOutputStream() {
public synchronized void close() throws java.io.IOException {
try {
JDBCBlob.this.setBytes(pos, toByteArray());
} catch (SQLException se) {
throw JavaSystem.toIOException(se);
} finally {
super.close();
}
}
};
}
/**
* Truncates the BLOB value that this Blob
* object represents to be len bytes in length.
*
* Note: If the value specified for pos
* is greater then the length+1 of the BLOB value then the
* behavior is undefined. Some JDBC drivers may throw a
* SQLException while other drivers may support this
* operation.
*
*
*
* HSQLDB-Specific Information:
*
* Starting with HSQLDB 2.0 this feature is fully supported.
*
* When built under JDK 1.6+ and the Blob instance is constructed as a
* result of calling JDBCConnection.createBlob(), this operation affects
* only the client-side value; it has no effect upon a value stored in a
* database because JDBCConnection.createBlob() constructs disconnected,
* initially empty Blob instances. To propagate the truncated Blob value to
* a database in this case, it is required to supply the Blob instance to
* an updating or inserting setXXX method of a Prepared or Callable
* Statement, or to supply the Blob instance to an updateXXX method of an
* updateable ResultSet.
*
*
*
*
* @param len the length, in bytes, to which the BLOB value
* that this Blob object represents should be truncated
* @exception SQLException if there is an error accessing the
* BLOB value or if len is less than 0
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.4, HSQLDB 1.7.2
* @revised JDK 1.6, HSQLDB 2.0
*/
public void truncate(final long len) throws SQLException {
final byte[] data = getData();
if (!m_createdByConnection) {
/** @todo - better error message */
throw JDBCUtil.notSupported();
}
if (len < 0 || len > data.length) {
throw JDBCUtil.outOfRangeArgument("len: " + len);
}
if (len == data.length) {
return;
}
byte[] newData = new byte[(int) len];
System.arraycopy(data, 0, newData, 0, (int) len);
checkClosed(); // limit possible race-condition with free()
setData(newData);
}
//------------------------- JDBC 4.0 -----------------------------------
/**
* This method frees the Blob object and releases the resources that
* it holds. The object is invalid once the free
* method is called.
*
* 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 if an error occurs releasing
* the Blob's resources
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.6, HSQLDB 2.0
*/
public synchronized void free() throws SQLException {
m_closed = true;
m_data = null;
}
/**
* Returns an InputStream object that contains a partial Blob value,
* starting with the byte specified by pos, which is length bytes in length.
*
* @param pos the offset to the first byte of the partial value to be retrieved.
* The first byte in the Blob is at position 1
* @param length the length in bytes of the partial value to be retrieved
* @return InputStream through which the partial Blob value can be read.
* @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
* in the Blob or if pos + length is greater than the number of bytes
* in the Blob
*
* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
* this method
* @since JDK 1.6, HSQLDB 2.0
*/
public InputStream getBinaryStream(long pos,
long length) throws SQLException {
final byte[] data = getData();
final int dlen = data.length;
if (pos < MIN_POS || pos > dlen) {
throw JDBCUtil.outOfRangeArgument("pos: " + pos);
}
pos--;
if (length < 0 || length > dlen - pos) {
throw JDBCUtil.outOfRangeArgument("length: " + length);
}
if (pos == 0 && length == dlen) {
return new ByteArrayInputStream(data);
}
final byte[] result = new byte[(int) length];
System.arraycopy(data, (int) pos, result, 0, (int) length);
return new ByteArrayInputStream(result);
}
// ---------------------- internal implementation --------------------------
public static final long MIN_POS = 1L;
public static final long MAX_POS = 1L + (long) Integer.MAX_VALUE;
private boolean m_closed;
private byte[] m_data;
private final boolean m_createdByConnection;
/**
* Constructs a new JDBCBlob instance wrapping the given octet sequence.
*
* This constructor is used internally to retrieve result set values as
* Blob objects, yet it must be public to allow access from other packages.
* As such (in the interest of efficiency) this object maintains a reference
* to the given octet sequence rather than making a copy; special care
* should be taken by external clients never to use this constructor with a
* byte array object that may later be modified externally.
*
* @param data the octet sequence representing the Blob value
* @throws SQLException if the argument is null
*/
public JDBCBlob(final byte[] data) throws SQLException {
if (data == null) {
throw JDBCUtil.nullArgument();
}
m_data = data;
m_createdByConnection = false;
}
protected JDBCBlob() {
m_data = new byte[0];
m_createdByConnection = true;
}
protected synchronized void checkClosed() throws SQLException {
if (m_closed) {
throw JDBCUtil.sqlException(ErrorCode.X_07501);
}
}
protected byte[] data() throws SQLException {
return getData();
}
private synchronized byte[] getData() throws SQLException {
checkClosed();
return m_data;
}
private synchronized void setData(byte[] data) throws SQLException {
checkClosed();
m_data = data;
}
}