/*
* @(#)SerialClob.java 1.17 07/06/25
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.sql.rowset.serial;
import java.sql.*;
import java.io.*;
/**
* A serialized mapping in the Java programming language of an SQL
* <code>CLOB</code> value.
* <P>
* The <code>SerialClob</code> class provides a constructor for creating
* an instance from a <code>Clob</code> object. Note that the <code>Clob</code>
* object should have brought the SQL <code>CLOB</code> value's data over
* to the client before a <code>SerialClob</code> object
* is constructed from it. The data of an SQL <code>CLOB</code> value can
* be materialized on the client as a stream of Unicode characters.
* <P>
* <code>SerialClob</code> methods make it possible to get a substring
* from a <code>SerialClob</code> object or to locate the start of
* a pattern of characters.
*
* @author Jonathan Bruce
*/
public class SerialClob implements Clob, Serializable, Cloneable {
/**
* A serialized array of characters containing the data of the SQL
* <code>CLOB</code> value that this <code>SerialClob</code> object
* represents.
*
* @serial
*/
private char buf[];
/**
* Internal Clob representation if SerialClob is intialized with a
* Clob
*/
private Clob clob;
/**
* The length in characters of this <code>SerialClob</code> object's
* internal array of characters.
*
* @serial
*/
private long len;
/**
* The original length in characters of tgus <code>SerialClob</code>
* objects internal array of characters.
*
* @serial
*/
private long origLen;
/**
* Constructs a <code>SerialClob</code> object that is a serialized version of
* the given <code>char</code> array.
* <p>
* The new <code>SerialClob</code> object is initialized with the data from the
* <code>char</code> array, thus allowing disconnected <code>RowSet</code>
* objects to establish a serialized <code>Clob</code> object without touching
* the data source.
*
* @param ch the char array representing the <code>Clob</code> object to be
* serialized
* @throws SerialException if an error occurs during serialization
* @throws SQLException if a SQL error occurs
*/
public SerialClob(char ch[]) throws SerialException, SQLException {
// %%% 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;
}
/**
* Constructs a <code>SerialClob</code> object that is a serialized
* version of the given <code>Clob</code> object.
* <P>
* The new <code>SerialClob</code> object is initialized with the
* data from the <code>Clob</code> object; therefore, the
* <code>Clob</code> object should have previously brought the
* SQL <code>CLOB</code> value's data over to the client from
* the database. Otherwise, the new <code>SerialClob</code> object
* object will contain no data.
* <p>
* Note: The <code>Clob</code> object supplied to this constructor cannot
* return <code>null</code> for the <code>Clob.getCharacterStream()</code>
* and <code>Clob.getAsciiStream</code> methods. This <code>SerialClob</code>
* constructor cannot serialize a <code>Clob</code> object in this instance
* and will throw an <code>SQLException</code> object.
*
* @param clob the <code>Clob</code> object from which this
* <code>SerialClob</code> object is to be constructed; cannot be null
* @throws SerialException if an error occurs during serialization
* @throws SQLException if a SQL error occurs in capturing the CLOB;
* if the <code>Clob</code> object is a null; or if both the
* <code>Clob.getCharacterStream()</code> and <code>Clob.getAsciiStream()</code>
* methods on the <code>Clob</code> return a null
* @see java.sql.Clob
*/
public SerialClob(Clob clob) throws SerialException, SQLException {
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 ( (((reader = new BufferedReader(clob.getCharacterStream())) == null)) &&
(clob.getAsciiStream() == null)) {
throw new SQLException("Invalid Clob object. Calls to getCharacterStream " +
"and getAsciiStream return null which cannot be serialized.");
}
try {
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;
}
/**
* Retrieves the number of characters in this <code>SerialClob</code>
* object's array of characters.
*
* @return a <code>long</code> indicating the length in characters of this
* <code>SerialClob</code> object's array of character
* @throws SerialException if an error occurs
*/
public long length() throws SerialException {
return len;
}
/**
* Returns this <code>SerialClob</code> object's data as a stream
* of Unicode characters. Unlike the related method, <code>getAsciiStream</code>,
* a stream is produced regardless of whether the <code>SerialClob</code> object
* was created with a <code>Clob</code> object or a <code>char</code> array.
*
* @return a <code>java.io.Reader</code> object containing this
* <code>SerialClob</code> object's data
* @throws SerialException if an error occurs
*/
public java.io.Reader getCharacterStream() throws SerialException {
return (java.io.Reader) new CharArrayReader(buf);
}
/**
* Retrieves the <code>CLOB</code> value designated by this <code>SerialClob</code>
* object as an ascii stream. This method forwards the <code>getAsciiStream</code>
* call to the underlying <code>Clob</code> object in the event that this
* <code>SerialClob</code> object is instantiated with a <code>Clob</code>
* object. If this <code>SerialClob</code> object is instantiated with
* a <code>char</code> array, a <code>SerialException</code> object is thrown.
*
* @return a <code>java.io.InputStream</code> object containing
* this <code>SerialClob</code> object's data
* @throws SerialException if this <code>SerialClob</code> object was not instantiated
* with a <code>Clob</code> object
* @throws SQLException if there is an error accessing the
* <code>CLOB</code> value represented by the <code>Clob</code> object that was
* used to create this <code>SerialClob</code> object
*/
public java.io.InputStream getAsciiStream() throws SerialException, SQLException {
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.");
}
}
/**
* Returns a copy of the substring contained in this
* <code>SerialClob</code> object, starting at the given position
* and continuing for the specified number or characters.
*
* @param pos the position of the first character in the substring
* to be copied; the first character of the
* <code>SerialClob</code> object is at position
* <code>1</code>; must not be less than <code>1</code>,
* and the sum of the starting position and the length
* of the substring must be less than the length of this
* <code>SerialClob</code> object
* @param length the number of characters in the substring to be
* returned; must not be greater than the length of
* this <code>SerialClob</code> object, and the
* sum of the starting position and the length
* of the substring must be less than the length of this
* <code>SerialClob</code> object
* @return a <code>String</code> object containing a substring of
* this <code>SerialClob</code> object beginning at the
* given position and containing the specified number of
* consecutive characters
* @throws SerialException if either of the arguments is out of bounds
*/
public String getSubString(long pos, int length) throws SerialException {
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());
}
}
/**
* Returns the position in this <code>SerialClob</code> object
* where the given <code>String</code> object begins, starting
* the search at the specified position. This method returns
* <code>-1</code> if the pattern is not found.
*
* @param searchStr the <code>String</code> object for which to
* search
* @param start the position in this <code>SerialClob</code> object
* at which to start the search; the first position is
* <code>1</code>; must not be less than <code>1</code> nor
* greater than the length of this <code>SerialClob</code> object
* @return the position at which the given <code>String</code> object
* begins, starting the search at the specified position;
* <code>-1</code> if the given <code>String</code> object is
* not found or the starting position is out of bounds; position
* numbering for the return value starts at <code>1</code>
* @throws SerialException if an error occurs locating the String signature
* @throws SQLException if there is an error accessing the Blob value
* from the database.
*/
public long position(String searchStr, long start)
throws SerialException, SQLException {
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
}
/**
* Returns the position in this <code>SerialClob</code> object
* where the given <code>Clob</code> signature begins, starting
* the search at the specified position. This method returns
* <code>-1</code> if the pattern is not found.
*
* @param searchStr the <code>Clob</code> object for which to search
* @param start the position in this <code>SerialClob</code> object
* at which to begin the search; the first position is
* <code>1</code>; must not be less than <code>1</code> nor
* greater than the length of this <code>SerialClob</code> object
* @return the position at which the given <code>Clob</code>
* object begins in this <code>SerialClob</code> object,
* at or after the specified starting position
* @throws SerialException if an error occurs locating the Clob signature
* @throws SQLException if there is an error accessing the Blob value
* from the database
*/
public long position(Clob searchStr, long start)
throws SerialException, SQLException {
return position(searchStr.getSubString(1,(int)searchStr.length()), start);
}
/**
* Writes the given Java <code>String</code> to the <code>CLOB</code>
* value that this <code>SerialClob</code> object represents, at the position
* <code>pos</code>.
*
* @param pos the position at which to start writing to the <code>CLOB</code>
* value that this <code>SerialClob</code> object represents; the first
* position is <code>1</code>; must not be less than <code>1</code> nor
* greater than the length of this <code>SerialClob</code> object
* @param str the string to be written to the <code>CLOB</code>
* value that this <code>SerialClob</code> object represents
* @return the number of characters written
* @throws SerialException if there is an error accessing the
* <code>CLOB</code> 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 <code>SerialClob</code> length; or the combined
* values of the length and offset is greater than the Clob buffer
*/
public int setString(long pos, String str) throws SerialException {
return (setString(pos, str, 0, str.length()));
}
/**
* Writes <code>len</code> characters of <code>str</code>, starting
* at character <code>offset</code>, to the <code>CLOB</code> value
* that this <code>Clob</code> represents.
*
* @param pos the position at which to start writing to the <code>CLOB</code>
* value that this <code>SerialClob</code> object represents; the first
* position is <code>1</code>; must not be less than <code>1</code> nor
* greater than the length of this <code>SerialClob</code> object
* @param str the string to be written to the <code>CLOB</code>
* value that this <code>Clob</code> object represents
* @param offset the offset into <code>str</code> to start reading
* the characters to be written
* @param length the number of characters to be written
* @return the number of characters written
* @throws SerialException if there is an error accessing the
* <code>CLOB</code> 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 <code>SerialClob</code> length; or the combined
* values of the length and offset is greater than the Clob buffer
*/
public int setString(long pos, String str, int offset, int length)
throws SerialException {
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;
}
/**
* Retrieves a stream to be used to write Ascii characters to the
* <code>CLOB</code> value that this <code>SerialClob</code> object represents,
* starting at position <code>pos</code>. This method forwards the
* <code>setAsciiStream()</code> call to the underlying <code>Clob</code> object in
* the event that this <code>SerialClob</code> object is instantiated with a
* <code>Clob</code> object. If this <code>SerialClob</code> object is instantiated
* with a <code>char</code> array, a <code>SerialException</code> object is thrown.
*
* @param pos the position at which to start writing to the
* <code>CLOB</code> object
* @return the stream to which ASCII encoded characters can be written
* @throws SerialException if SerialClob is not instantiated with a
* Clob object that supports <code>setAsciiStream</code>
* @throws SQLException if there is an error accessing the
* <code>CLOB</code> value
* @see #getAsciiStream
*/
public java.io.OutputStream setAsciiStream(long pos)
throws SerialException, SQLException {
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");
}
}
/**
* Retrieves a stream to be used to write a stream of Unicode characters
* to the <code>CLOB</code> value that this <code>SerialClob</code> object
* represents, at position <code>pos</code>. This method forwards the
* <code>setCharacterStream()</code> call to the underlying <code>Clob</code>
* object in the event that this <code>SerialClob</code> object is instantiated with a
* <code>Clob</code> object. If this <code>SerialClob</code> object is instantiated with
* a <code>char</code> array, a <code>SerialException</code> is thrown.
*
* @param pos the position at which to start writing to the
* <code>CLOB</code> value
*
* @return a stream to which Unicode encoded characters can be written
* @throws SerialException if the SerialClob is not instantiated with
* a Clob object that supports <code>setCharacterStream</code>
* @throws SQLException if there is an error accessing the
* <code>CLOB</code> value
* @see #getCharacterStream
*/
public java.io.Writer setCharacterStream(long pos)
throws SerialException, SQLException {
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");
}
}
/**
* Truncates the <code>CLOB</code> value that this <code>SerialClob</code>
* object represents so that it has a length of <code>len</code>
* characters.
* <p>
* Truncating a <code>SerialClob</code> object to length 0 has the effect of
* clearing its contents.
*
* @param length the length, in bytes, to which the <code>CLOB</code>
* value should be truncated
* @throws SQLException if there is an error accessing the
* <code>CLOB</code> value
*/
public void truncate(long length) throws SerialException {
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();
}
}
}
public Reader getCharacterStream(long pos, long length) throws SQLException {
throw new java.lang.UnsupportedOperationException("Not supported");
}
public void free() throws SQLException {
throw new java.lang.UnsupportedOperationException("Not supported");
}
/**
* The identifier that assists in the serialization of this <code>SerialClob</code>
* object.
*/
static final long serialVersionUID = -1662519690087375313L;
}
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