SerialBlob (Java SE 17 & JDK 17)
Description: declaration: module: java.sql.rowset, package: javax.sql.rowset.serial, class: SerialBlob
Keywords: javax.sql.rowset.serial.SerialBlob class

Module java.sql.rowset
Package javax.sql.rowset.serial

# Class SerialBlob

java.lang.Object
javax.sql.rowset.serial.SerialBlob

All Implemented Interfaces:
  `Serializable`, `Cloneable`, `Blob`

public class SerialBlob extends Object implements Blob, Serializable, Cloneable
A serialized mapping in the Java programming language of an SQL `BLOB` value.

The `SerialBlob` class provides a constructor for creating an instance from a `Blob` object. Note that the `Blob` object should have brought the SQL `BLOB` value's data over to the client before a `SerialBlob` object is constructed from it. The data of an SQL `BLOB` value can be materialized on the client as an array of bytes (using the method `Blob.getBytes`) or as a stream of uninterpreted bytes (using the method `Blob.getBinaryStream`).

`SerialBlob` methods make it possible to make a copy of a `SerialBlob` object as an array of bytes or as a stream. They also make it possible to locate a given pattern of bytes or a `Blob` object within a `SerialBlob` object and to update or truncate a `Blob` object.

## Thread safety

A SerialBlob is not safe for use by multiple concurrent threads. If a SerialBlob is to be used by more than one thread then access to the SerialBlob should be controlled by appropriate synchronization.

Since:
  1.5
See Also:
  - Serialized Form

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `SerialBlob(byte[] b)`
  Constructs a `SerialBlob` object that is a serialized version of the given `byte` array.
  `SerialBlob(Blob blob)`
  Constructs a `SerialBlob` object that is a serialized version of the given `Blob` object.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Object`
  `clone()`
  Returns a clone of this `SerialBlob`.
  `boolean`
  `equals(Object obj)`
  Compares this SerialBlob to the specified object.
  `void`
  `free()`
  This method frees the `SerialBlob` object and releases the resources that it holds.
  `InputStream`
  `getBinaryStream()`
  Returns this `SerialBlob` object as an input stream.
  `InputStream`
  `getBinaryStream(long pos, long length)`
  Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
  `byte[]`
  `getBytes(long pos, int length)`
  Copies the specified number of bytes, starting at the given position, from this `SerialBlob` object to another array of bytes.
  `int`
  `hashCode()`
  Returns a hash code for this `SerialBlob`.
  `long`
  `length()`
  Retrieves the number of bytes in this `SerialBlob` object's array of bytes.
  `long`
  `position(byte[] pattern, long start)`
  Returns the position in this `SerialBlob` object where the given pattern of bytes begins, starting the search at the specified position.
  `long`
  `position(Blob pattern, long start)`
  Returns the position in this `SerialBlob` object where the given `Blob` object begins, starting the search at the specified position.
  `OutputStream`
  `setBinaryStream(long pos)`
  Retrieves a stream that can be used to write to the `BLOB` value that this `Blob` object represents.
  `int`
  `setBytes(long pos, byte[] bytes)`
  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.
  `int`
  `setBytes(long pos, byte[] bytes, int offset, int 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.
  `void`
  `truncate(long length)`
  Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length.

  ### Methods declared in class java.lang.Object

  `finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### SerialBlob

    public SerialBlob(byte[] b) throws SerialException, SQLException
    Constructs a `SerialBlob` object that is a serialized version of the given `byte` array.

    The new `SerialBlob` object is initialized with the data from the `byte` array, thus allowing disconnected `RowSet` objects to establish serialized `Blob` objects without touching the data source.

    Parameters:
      `b` - the `byte` array containing the data for the `Blob` object to be serialized
    Throws:
      `SerialException` - if an error occurs during serialization
      `SQLException` - if a SQL errors occurs

  - ### SerialBlob

    public SerialBlob(Blob blob) throws SerialException, SQLException
    Constructs a `SerialBlob` object that is a serialized version of the given `Blob` object.

    The new `SerialBlob` object is initialized with the data from the `Blob` object; therefore, the `Blob` object should have previously brought the SQL `BLOB` value's data over to the client from the database. Otherwise, the new `SerialBlob` object will contain no data.

    Parameters:
      `blob` - the `Blob` object from which this `SerialBlob` object is to be constructed; cannot be null.
    Throws:
      `SerialException` - if an error occurs during serialization
      `SQLException` - if the `Blob` passed to this to this constructor is a `null`.
    See Also:
      - `Blob`

- ## Method Details

  - ### getBytes

    public byte[] getBytes(long pos, int length) throws SerialException
    Copies the specified number of bytes, starting at the given position, from this `SerialBlob` object to another array of bytes.

    Note that if the given number of bytes to be copied is larger than the length of this `SerialBlob` object's array of bytes, the given number will be shortened to the array's length.

    Specified by:
      `getBytes` in interface `Blob`
    Parameters:
      `pos` - the ordinal position of the first byte in this `SerialBlob` object to be copied; numbering starts at `1`; must not be less than `1` and must be less than or equal to the length of this `SerialBlob` object
      `length` - the number of bytes to be copied
    Returns:
      an array of bytes that is a copy of a region of this `SerialBlob` object, starting at the given position and containing the given number of consecutive bytes
    Throws:
      `SerialException` - if the given starting position is out of bounds; if `free` had previously been called on this object
    See Also:
      - `Blob.setBytes(long, byte[])`

  - ### length

    public long length() throws SerialException
    Retrieves the number of bytes in this `SerialBlob` object's array of bytes.
    Specified by:
      `length` in interface `Blob`
    Returns:
      a `long` indicating the length in bytes of this `SerialBlob` object's array of bytes
    Throws:
      `SerialException` - if an error occurs; if `free` had previously been called on this object

  - ### getBinaryStream

    public InputStream getBinaryStream() throws SerialException
    Returns this `SerialBlob` object as an input stream. Unlike the related method, `setBinaryStream`, a stream is produced regardless of whether the `SerialBlob` was created with a `Blob` object or a `byte` array.
    Specified by:
      `getBinaryStream` in interface `Blob`
    Returns:
      a `java.io.InputStream` object that contains this `SerialBlob` object's array of bytes
    Throws:
      `SerialException` - if an error occurs; if `free` had previously been called on this object
    See Also:
      - `setBinaryStream(long)`

  - ### position

    public long position(byte[] pattern, long start) throws SerialException, SQLException
    Returns the position in this `SerialBlob` object where the given pattern of bytes begins, starting the search at the specified position.
    Specified by:
      `position` in interface `Blob`
    Parameters:
      `pattern` - the pattern of bytes for which to search
      `start` - the position of the byte in this `SerialBlob` object from which to begin the search; the first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object
    Returns:
      the position in this `SerialBlob` object where the given pattern begins, starting at the specified position; `-1` if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at `1`
    Throws:
      `SerialException` - if an error occurs when serializing the blob; if `free` had previously been called on this object
      `SQLException` - if there is an error accessing the `BLOB` value from the database

  - ### position

    public long position(Blob pattern, long start) throws SerialException, SQLException
    Returns the position in this `SerialBlob` object where the given `Blob` object begins, starting the search at the specified position.
    Specified by:
      `position` in interface `Blob`
    Parameters:
      `pattern` - the `Blob` object for which to search;
      `start` - the position of the byte in this `SerialBlob` object from which to begin the search; the first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object
    Returns:
      the position in this `SerialBlob` object where the given `Blob` object begins, starting at the specified position; `-1` if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at `1`
    Throws:
      `SerialException` - if an error occurs when serializing the blob; if `free` had previously been called on this object
      `SQLException` - if there is an error accessing the `BLOB` value from the database

  - ### setBytes

    public int setBytes(long pos, byte[] bytes) throws SerialException, SQLException
    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.
    Specified by:
      `setBytes` in interface `Blob`
    Parameters:
      `pos` - the position in the SQL `BLOB` value at which to start writing. The first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object.
      `bytes` - the array of bytes to be written to the `BLOB` value that this `Blob` object represents
    Returns:
      the number of bytes written
    Throws:
      `SerialException` - if there is an error accessing the `BLOB` value; or if an invalid position is set; if an invalid offset value is set; if `free` had previously been called on this object
      `SQLException` - if there is an error accessing the `BLOB` value from the database
    See Also:
      - `getBytes(long, int)`

  - ### setBytes

    public int setBytes(long pos, byte[] bytes, int offset, int length) throws SerialException, SQLException
    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.
    Specified by:
      `setBytes` in interface `Blob`
    Parameters:
      `pos` - the position in the `BLOB` object at which to start writing. The first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object.
      `bytes` - the array of bytes to be written to the `BLOB` value
      `offset` - the offset in the `byte` array at which to start reading the bytes. The first offset position is `0`; must not be less than `0` nor greater than the length of the `byte` array
      `length` - the number of bytes to be written to the `BLOB` value from the array of bytes bytes.
    Returns:
      the number of bytes written
    Throws:
      `SerialException` - if there is an error accessing the `BLOB` value; if an invalid position is set; if an invalid offset value is set; if number of bytes to be written is greater than the `SerialBlob` length; or the combined values of the length and offset is greater than the Blob buffer; if `free` had previously been called on this object
      `SQLException` - if there is an error accessing the `BLOB` value from the database.
    See Also:
      - `getBytes(long, int)`

  - ### setBinaryStream

    public OutputStream setBinaryStream(long pos) throws SerialException, SQLException
    Retrieves a stream that can be used to write to the `BLOB` value that this `Blob` object represents. The stream begins at position `pos`. This method forwards the `setBinaryStream()` call to the underlying `Blob` in the event that this `SerialBlob` object is instantiated with a `Blob`. If this `SerialBlob` is instantiated with a `byte` array, a `SerialException` is thrown.
    Specified by:
      `setBinaryStream` in interface `Blob`
    Parameters:
      `pos` - the position in the `BLOB` value at which to start writing
    Returns:
      a `java.io.OutputStream` object to which data can be written
    Throws:
      `SQLException` - if there is an error accessing the `BLOB` value
      `SerialException` - if the SerialBlob in not instantiated with a `Blob` object that supports `setBinaryStream()`; if `free` had previously been called on this object
    See Also:
      - `getBinaryStream()`

  - ### truncate

    public void truncate(long length) throws SerialException
    Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length.
    Specified by:
      `truncate` in interface `Blob`
    Parameters:
      `length` - the length, in bytes, to which the `BLOB` value that this `Blob` object represents should be truncated
    Throws:
      `SerialException` - if there is an error accessing the Blob value; or the length to truncate is greater that the SerialBlob length; if `free` had previously been called on this object

  - ### getBinaryStream

    public InputStream getBinaryStream(long pos, long length) throws SQLException
    Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
    Specified by:
      `getBinaryStream` in interface `Blob`
    Parameters:
      `pos` - the offset to the first byte of the partial value to be retrieved. The first byte in the `Blob` is at position 1
      `length` - the length in bytes of the partial value to be retrieved
    Returns:
      `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`
      `SerialException` - if the `free` method had been previously called on this object
    Since:
      1.6

  - ### free

    public void free() throws SQLException
    This method frees the `SerialBlob` object and releases the resources that it holds. The object is invalid once the `free` method is called.

    If `free` is called multiple times, the subsequent calls to `free` are treated as a no-op.

    Specified by:
      `free` in interface `Blob`
    Throws:
      `SQLException` - if an error occurs releasing the Blob's resources
    Since:
      1.6

  - ### equals

    public boolean equals(Object obj)
    Compares this SerialBlob to the specified object. The result is `true` if and only if the argument is not `null` and is a `SerialBlob` object that represents the same sequence of bytes as this object.
    Overrides:
      `equals` in class `Object`
    Parameters:
      `obj` - The object to compare this `SerialBlob` against
    Returns:
      `true` if the given object represents a `SerialBlob` equivalent to this SerialBlob, `false` otherwise
    See Also:
      - `Object.hashCode()`
      - `HashMap`

  - ### hashCode

    public int hashCode()
    Returns a hash code for this `SerialBlob`.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      a hash code value for this object.
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(java.lang.Object)`

  - ### clone

    public Object clone()
    Returns a clone of this `SerialBlob`. The copy will contain a reference to a clone of the internal byte array, not a reference to the original internal byte array of this `SerialBlob` object. The underlying `Blob` object will be set to null.
    Overrides:
      `clone` in class `Object`
    Returns:
      a clone of this SerialBlob
    See Also:
      - `Cloneable`