org.sqldroid.SQLDroidClob Maven / Gradle / Ivy
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package org.sqldroid;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* The mapping in the Java programming language for the SQL CLOB type.
* An SQL CLOB is a built-in type that stores a Character Large Object as a column value
* in a row of a database table. By default drivers implement a Clob object using an SQL
* locator(CLOB), which means that a Clob object contains a logical pointer to the
* SQL CLOB data rather than the data itself. A Clob object is valid for the duration
* of the transaction in which it was created.
* The Clob interface provides methods for getting the length of an SQL CLOB
* (Character Large Object) value, for materializing a CLOB value on the client, and for
* searching for a substring or CLOB object within a CLOB value.
* Methods in the interfaces {@link ResultSet}, {@link CallableStatement}, and {@link PreparedStatement}, such as
* getClob and setClob allow a programmer to access an SQL CLOB value.
* In addition, this interface has methods for updating a CLOB value.
*
* Based on ClobImpl from DataNucleus project. Thanks to DataNucleus contributors.
* @see ClobImpl from DataNucleus Project
*
*/
public class SQLDroidClob implements Clob
{
private String string;
private long length;
/** Reader for the operations that work that way. */
private StringReader reader;
/** InputStream for operations that work that way. TODO Rationalise with reader above. */
private InputStream inputStream;
/** Whether we have already freed resources. */
boolean freed = false;
/**
* Constructor taking a string.
* @param string The string.
*/
public SQLDroidClob(String string)
{
if (string == null)
{
throw new IllegalArgumentException("String cannot be null");
}
this.string = string;
this.length = string.length();
}
public long length() throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
return length;
}
public void truncate(long len) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
public InputStream getAsciiStream() throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
if (inputStream == null)
{
inputStream = new ByteArrayInputStream(string.getBytes());
}
return inputStream;
}
public OutputStream setAsciiStream(long pos) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
public Reader getCharacterStream() throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
if (reader == null)
{
this.reader = new StringReader(string);
}
return reader;
}
public Writer setCharacterStream(long pos) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
/**
* Free the Blob object and releases the resources that it holds.
* The object is invalid once the free method is called.
* @throws SQLException if an error occurs
*/
public void free() throws SQLException
{
if (freed)
{
return;
}
string = null;
if (reader != null)
{
reader.close();
}
if (inputStream != null)
{
try
{
inputStream.close();
}
catch (IOException ioe)
{
// Do nothing
}
}
freed = true;
}
/**
* Returns a Reader object that contains a partial Clob value, starting with the character specified by pos,
* which is length characters in length.
* @param pos the offset to the first byte of the partial value to be retrieved.
* The first byte in the Clob is at position 1
* @param length the length in bytes of the partial value to be retrieved
*/
public Reader getCharacterStream(long pos, long length) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
// TODO Use pos, length
if (reader == null)
{
this.reader = new StringReader(string);
}
return reader;
}
public String getSubString(long pos, int length) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
if(pos > Integer.MAX_VALUE)
{
throw new IllegalArgumentException("Initial position cannot be larger than " + Integer.MAX_VALUE);
}
else if((pos + length - 1) > length())
{
throw new IndexOutOfBoundsException("The requested substring is greater than the actual length of the Clob String.");
}
return string.substring((int)pos -1, (int)pos + length -1);
}
public int setString(long pos, String str) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
public int setString(long pos, String str, int offset, int len) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
public long position(String searchstr, long start) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
public long position(Clob searchstr, long start) throws SQLException
{
if (freed)
{
throw new SQLException("free() has been called");
}
throw new UnsupportedOperationException();
}
}