SerialClobpublic class SerialClob extends Object implements Serializable, Cloneable, ClobA serialized mapping in the Java programming language of an SQL
CLOB value.
The SerialClob class provides a constructor for creating
an instance from a Clob object. Note that the Clob
object should have brought the SQL CLOB value's data over
to the client before a SerialClob object
is constructed from it. The data of an SQL CLOB value can
be materialized on the client as a stream of Unicode characters.
SerialClob methods make it possible to get a substring
from a SerialClob object or to locate the start of
a pattern of characters. |
| Fields Summary |
|---|
| private char[] | bufA serialized array of characters containing the data of the SQL
CLOB value that this SerialClob object
represents. | | private Clob | clobInternal Clob representation if SerialClob is intialized with a
Clob | | private long | lenThe length in characters of this SerialClob object's
internal array of characters. | | private long | origLenThe original length in characters of tgus SerialClob
objects internal array of characters. | | static final long | serialVersionUIDThe identifier that assists in the serialization of this SerialClob
object. |
| Constructors Summary |
|---|
public SerialClob(char[] ch)Constructs a SerialClob object that is a serialized version of
the given char array.
The new SerialClob object is initialized with the data from the
char array, thus allowing disconnected RowSet
objects to establish a serialized Clob object without touching
the data source.
// %%% JMB. Agreed. Add code here to throw a SQLException if no
// support is available for locatorsUpdateCopy=false
// Serializing locators is not supported.
len = ch.length;
buf = new char[(int)len];
for (int i = 0; i < len ; i++){
buf[i] = ch[i];
}
origLen = len;
| public SerialClob(Clob clob)Constructs a SerialClob object that is a serialized
version of the given Clob object.
The new SerialClob object is initialized with the
data from the Clob object; therefore, the
Clob object should have previously brought the
SQL CLOB value's data over to the client from
the database. Otherwise, the new SerialClob object
object will contain no data.
Note: The Clob object supplied to this constructor cannot
return null for the Clob.getCharacterStream()
and Clob.getAsciiStream methods. This SerialClob
constructor cannot serialize a Clob object in this instance
and will throw an SQLException object.
if (clob == null) {
throw new SQLException("Cannot instantiate a SerialClob " +
"object with a null Clob object");
}
len = clob.length();
this.clob = clob;
buf = new char[(int)len];
int read = 0;
int offset = 0;
BufferedReader reader;
if (clob.getCharacterStream() == null || clob.getAsciiStream() == null) {
throw new SQLException("Invalid Clob object. Calls to getCharacterStream " +
"or getAsciiStream return null which cannot be serialized.");
}
try {
reader = new BufferedReader(clob.getCharacterStream());
do {
read = reader.read(buf, offset, (int)(len - offset));
offset += read;
} while (read > 0);
} catch (java.io.IOException ex) {
throw new SerialException("SerialClob: " + ex.getMessage());
}
origLen = len;
|
| Methods Summary |
|---|
| public java.io.InputStream | getAsciiStream()Retrieves the CLOB value designated by this SerialClob
object as an ascii stream. This method forwards the getAsciiStream
call to the underlying Clob object in the event that this
SerialClob object is instantiated with a Clob
object. If this SerialClob object is instantiated with
a char array, a SerialException object is thrown.
if (this.clob != null) {
return this.clob.getAsciiStream();
} else {
throw new SerialException("Unsupported operation. SerialClob cannot " +
"return a the CLOB value as an ascii stream, unless instantiated " +
"with a fully implemented Clob object.");
}
| | public java.io.Reader | getCharacterStream()Returns this SerialClob object's data as a stream
of Unicode characters. Unlike the related method, getAsciiStream,
a stream is produced regardless of whether the SerialClob object
was created with a Clob object or a char array.
return (java.io.Reader) new CharArrayReader(buf);
| | public java.lang.String | getSubString(long pos, int length)Returns a copy of the substring contained in this
SerialClob object, starting at the given position
and continuing for the specified number or characters.
if (pos < 1 || pos > this.length()) {
throw new SerialException("Invalid position in BLOB object set");
}
if ((pos-1) + length > this.length()) {
throw new SerialException("Invalid position and substring length");
}
try {
return new String(buf, (int)pos - 1, length);
} catch (StringIndexOutOfBoundsException e) {
throw new SerialException("StringIndexOutOfBoundsException: " +
e.getMessage());
}
| | public long | length()Retrieves the number of characters in this SerialClob
object's array of characters.
return len;
| | public long | position(java.lang.String searchStr, long start)Returns the position in this SerialClob object
where the given String object begins, starting
the search at the specified position. This method returns
-1 if the pattern is not found.
if (start < 1 || start > len) {
return -1;
}
char pattern[] = searchStr.toCharArray();
int pos = (int)start-1;
int i = 0;
long patlen = pattern.length;
while (pos < len) {
if (pattern[i] == buf[pos]) {
if (i + 1 == patlen) {
return (pos + 1) - (patlen - 1);
}
i++; pos++; // increment pos, and i
} else if (pattern[i] != buf[pos]) {
pos++; // increment pos only
}
}
return -1; // not found
| | public long | position(java.sql.Clob searchStr, long start)Returns the position in this SerialClob object
where the given Clob signature begins, starting
the search at the specified position. This method returns
-1 if the pattern is not found.
char cPattern[] = null;
try {
java.io.Reader r = searchStr.getCharacterStream();
cPattern = new char[(int)searchStr.length()];
r.read(cPattern);
} catch (IOException e) {
throw new SerialException("Error streaming Clob search data");
}
return position(new String(cPattern), start);
| | public java.io.OutputStream | setAsciiStream(long pos)Retrieves a stream to be used to write Ascii characters to the
CLOB value that this SerialClob object represents,
starting at position pos. This method forwards the
setAsciiStream() call to the underlying Clob object in
the event that this SerialClob object is instantiated with a
Clob object. If this SerialClob object is instantiated
with a char array, a SerialException object is thrown.
if (this.clob.setAsciiStream(pos) != null) {
return this.clob.setAsciiStream(pos);
} else {
throw new SerialException("Unsupported operation. SerialClob cannot " +
"return a writable ascii stream\n unless instantiated with a Clob object " +
"that has a setAsciiStream() implementation");
}
| | public java.io.Writer | setCharacterStream(long pos)Retrieves a stream to be used to write a stream of Unicode characters
to the CLOB value that this SerialClob object
represents, at position pos. This method forwards the
setCharacterStream() call to the underlying Clob
object in the event that this SerialClob object is instantiated with a
Clob object. If this SerialClob object is instantiated with
a char array, a SerialException is thrown.
if (this.clob.setCharacterStream(pos) != null) {
return this.clob.setCharacterStream(pos);
} else {
throw new SerialException("Unsupported operation. SerialClob cannot " +
"return a writable character stream\n unless instantiated with a Clob object " +
"that has a setCharacterStream implementation");
}
| | public int | setString(long pos, java.lang.String str, int offset, int length)Writes len characters of str, starting
at character offset, to the CLOB value
that this Clob represents.
String temp = str.substring(offset);
char cPattern[] = temp.toCharArray();
if (offset < 0 || offset > str.length()) {
throw new SerialException("Invalid offset in byte array set");
}
if (pos < 1 || pos > this.length()) {
throw new SerialException("Invalid position in BLOB object set");
}
if ((long)(length) > origLen) {
throw new SerialException("Buffer is not sufficient to hold the value");
}
if ((length + offset) > str.length()) {
// need check to ensure length + offset !> bytes.length
throw new SerialException("Invalid OffSet. Cannot have combined offset " +
" and length that is greater that the Blob buffer");
}
int i = 0;
pos--; //values in the array are at position one less
while ( i < length || (offset + i +1) < (str.length() - offset ) ) {
this.buf[(int)pos + i ] = cPattern[offset + i ];
i++;
}
return i;
| | public int | setString(long pos, java.lang.String str)Writes the given Java String to the CLOB
value that this SerialClob object represents, at the position
pos.
return (setString(pos, str, 0, str.length()));
| | public void | truncate(long length)Truncates the CLOB value that this SerialClob
object represents so that it has a length of len
characters.
Truncating a SerialClob object to length 0 has the effect of
clearing its contents.
if (length > len) {
throw new SerialException
("Length more than what can be truncated");
} else {
len = length;
// re-size the buffer
if (len == 0) {
buf = new char[] {};
} else {
buf = (this.getSubString(1, (int)len)).toCharArray();
}
}
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