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	/*
	* Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.sql.rowset.serial;

	import java.sql.*;
	import java.io.*;
	import java.util.Arrays;

	/**
	* 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.
	*
	* <h3> Thread safety </h3>
	*
	* <p> A SerialClob is not safe for use by multiple concurrent threads. If a
	* SerialClob is to be used by more than one thread then access to the SerialClob
	* should be controlled by appropriate synchronization.
	*
	* @author Jonathan Bruce
	* @since 1.5
	*/
	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 initialized with a
	* Clob. Null if SerialClob is initialized with a char[].
	*/
	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 this <code>SerialClob</code>
	* object's 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;
	clob = null;
	}

	/**
	* 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 must
	* return non-null for both 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 either of the
	* <code>Clob.getCharacterStream()</code> and <code>Clob.getAsciiStream()</code>
	* methods on the <code>Clob</code> returns 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;

	try (Reader charStream = clob.getCharacterStream()) {
	if (charStream == null) {
	throw new SQLException("Invalid Clob object. The call to getCharacterStream " +
	"returned null which cannot be serialized.");
	}

	// Note: get an ASCII stream in order to null-check it,
	// even though we don't do anything with it.
	try (InputStream asciiStream = clob.getAsciiStream()) {
	if (asciiStream == null) {
	throw new SQLException("Invalid Clob object. The call to getAsciiStream " +
	"returned null which cannot be serialized.");
	}
	}

	try (Reader reader = new BufferedReader(charStream)) {
	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;
	* if {@code free} had previously been called on this object
	*/
	public long length() throws SerialException {
	isValid();
	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;
	* if {@code free} had previously been called on this object
	*/
	public java.io.Reader getCharacterStream() throws SerialException {
	isValid();
	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} object was not
	* instantiated with a <code>Clob</code> object;
	* if {@code free} had previously been called on this 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 {
	isValid();
	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;
	* if {@code free} had previously been called on this object
	*/
	public String getSubString(long pos, int length) throws SerialException {

	isValid();
	if (pos < 1 \|\| pos > this.length()) {
	throw new SerialException("Invalid position in SerialClob 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 the {@code free} method had been
	* previously called on this object
	* @throws SQLException if there is an error accessing the Clob value
	* from the database.
	*/
	public long position(String searchStr, long start)
	throws SerialException, SQLException {
	isValid();
	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;
	* if the {@code free} method had been previously called on this object
	* @throws SQLException if there is an error accessing the Clob value
	* from the database
	*/
	public long position(Clob searchStr, long start)
	throws SerialException, SQLException {
	isValid();
	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;
	* if the {@code free} method had been previously called on this object
	*/
	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;
	* if the {@code free} method had been previously called on this object
	*/
	public int setString(long pos, String str, int offset, int length)
	throws SerialException {
	isValid();
	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 Clob 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;
	* if the {@code free} method had been previously called on this object
	* @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 {
	isValid();
	if (this.clob != 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;
	* if the {@code free} method had been previously called on this object
	* @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 {
	isValid();
	if (this.clob != 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 SerialException if there is an error accessing the
	* <code>CLOB</code> value;
	* if the {@code free} method had been previously called on this object
	*/
	public void truncate(long length) throws SerialException {
	isValid();
	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();
	}
	}
	}


	/**
	* Returns a {@code Reader} object that contains a partial
	* {@code SerialClob} value, starting
	* with the character specified by pos, which is length characters in length.
	*
	* @param pos the offset to the first character of the partial value to
	* be retrieved. The first character in the {@code SerialClob} is at position 1.
	* @param length the length in characters of the partial value to be retrieved.
	* @return {@code Reader} through which the partial {@code SerialClob}
	* value can be read.
	* @throws SQLException if pos is less than 1 or if pos is greater than the
	* number of characters in the {@code SerialClob} or if pos + length
	* is greater than the number of characters in the {@code SerialClob};
	* @throws SerialException if the {@code free} method had been previously
	* called on this object
	* @since 1.6
	*/
	public Reader getCharacterStream(long pos, long length) throws SQLException {
	isValid();
	if (pos < 1 \|\| pos > len) {
	throw new SerialException("Invalid position in Clob object set");
	}

	if ((pos-1) + length > len) {
	throw new SerialException("Invalid position and substring length");
	}
	if (length <= 0) {
	throw new SerialException("Invalid length specified");
	}
	return new CharArrayReader(buf, (int)pos, (int)length);
	}

	/**
	* This method frees the {@code SerialClob} object and releases the
	* resources that it holds.
	* The object is invalid once the {@code free} method is called.
	* <p>
	* If {@code free} is called multiple times, the subsequent
	* calls to {@code free} are treated as a no-op.
	* </P>
	* @throws SQLException if an error occurs releasing
	* the Clob's resources
	* @since 1.6
	*/
	public void free() throws SQLException {
	if (buf != null) {
	buf = null;
	if (clob != null) {
	clob.free();
	}
	clob = null;
	}
	}

	/**
	* Compares this SerialClob to the specified object. The result is {@code
	* true} if and only if the argument is not {@code null} and is a {@code
	* SerialClob} object that represents the same sequence of characters as this
	* object.
	*
	* @param obj The object to compare this {@code SerialClob} against
	*
	* @return {@code true} if the given object represents a {@code SerialClob}
	* equivalent to this SerialClob, {@code false} otherwise
	*
	*/
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof SerialClob) {
	SerialClob sc = (SerialClob)obj;
	if (this.len == sc.len) {
	return Arrays.equals(buf, sc.buf);
	}
	}
	return false;
	}

	/**
	* Returns a hash code for this {@code SerialClob}.
	* @return a hash code value for this object.
	*/
	public int hashCode() {
	return ((31 + Arrays.hashCode(buf)) * 31 + (int)len) * 31 + (int)origLen;
	}

	/**
	* Returns a clone of this {@code SerialClob}. The copy will contain a
	* reference to a clone of the internal character array, not a reference
	* to the original internal character array of this {@code SerialClob} object.
	* The underlying {@code Clob} object will be set to null.
	*
	* @return a clone of this SerialClob
	*/
	public Object clone() {
	try {
	SerialClob sc = (SerialClob) super.clone();
	sc.buf = (buf != null) ? Arrays.copyOf(buf, (int)len) : null;
	sc.clob = null;
	return sc;
	} catch (CloneNotSupportedException ex) {
	// this shouldn't happen, since we are Cloneable
	throw new InternalError();
	}
	}

	/**
	* readObject is called to restore the state of the SerialClob from
	* a stream.
	*/
	private void readObject(ObjectInputStream s)
	throws IOException, ClassNotFoundException {

	ObjectInputStream.GetField fields = s.readFields();
	char[] tmp = (char[])fields.get("buf", null);
	if (tmp == null)
	throw new InvalidObjectException("buf is null and should not be!");
	buf = tmp.clone();
	len = fields.get("len", 0L);
	if (buf.length != len)
	throw new InvalidObjectException("buf is not the expected size");
	origLen = fields.get("origLen", 0L);
	clob = (Clob) fields.get("clob", null);
	}

	/**
	* writeObject is called to save the state of the SerialClob
	* to a stream.
	*/
	private void writeObject(ObjectOutputStream s)
	throws IOException, ClassNotFoundException {

	ObjectOutputStream.PutField fields = s.putFields();
	fields.put("buf", buf);
	fields.put("len", len);
	fields.put("origLen", origLen);
	// Note: this check to see if it is an instance of Serializable
	// is for backwards compatibility
	fields.put("clob", clob instanceof Serializable ? clob : null);
	s.writeFields();
	}

	/**
	* Check to see if this object had previously had its {@code free} method
	* called
	*
	* @throws SerialException
	*/
	private void isValid() throws SerialException {
	if (buf == null) {
	throw new SerialException("Error: You cannot call a method on a "
	+ "SerialClob instance once free() has been called.");
	}
	}

	/**
	* The identifier that assists in the serialization of this {@code SerialClob}
	* object.
	*/
	static final long serialVersionUID = -1662519690087375313L;
	}

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