/************************************************************************
* 
*  Licensed to the Apache Software Foundation (ASF) under one
*  or more contributor license agreements.  See the NOTICE file
*  distributed with this work for additional information
*  regarding copyright ownership.  The ASF licenses this file
*  to you under the Apache License, Version 2.0 (the
*  "License"); you may not use this file except in compliance
*  with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing,
*  software distributed under the License is distributed on an
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
*  KIND, either express or implied.  See the License for the
*  specific language governing permissions and limitations
*  under the License.
*
************************************************************************/
package org.odftoolkit.odfdom.type;

import java.util.regex.Pattern;

/**
 * This class represents the in OpenDocument format used data type {@odf.datatype textEncoding}
 */
public class TextEncoding implements OdfDataType {

	private String mTextEncoding;
	private static final Pattern textEncodingPattern = Pattern.compile("^[A-Za-z][A-Za-z0-9._\\-]*$");
	
	/**
	 * Construct TextEncoding by the parsing the given string
	 *
	 * @param textEncoding
	 *            The String to be parsed into TextEncoding
	 * @throws IllegalArgumentException if the given argument is not a valid TextEncoding
	 */
	public TextEncoding(String textEncoding) throws IllegalArgumentException {
		if (!isValid(textEncoding)) {
			throw new IllegalArgumentException(
					"parameter is invalid for datatype TextEncoding");
		}
		mTextEncoding = textEncoding;
	}

	/**
	 * Returns a String Object representing this TextEncoding's value
	 *
	 * @return return a string representation of the value of this TextEncoding
	 *         object
	 */
	@Override
	public String toString() {
		return mTextEncoding;
	}

	/**
	 * Returns a TextEncoding instance representing the specified String value
	 *
	 * @param stringValue
	 *            a String value
	 * @return return a TextEncoding instance representing stringValue
	 * @throws IllegalArgumentException if the given argument is not a valid TextEncoding
	 */
	public static TextEncoding valueOf(String stringValue)
			throws IllegalArgumentException {
		return new TextEncoding(stringValue);
	}

	/**
	 * check if the specified String instance is a valid {@odf.datatype textEncoding} data type
	 *
	 * @param stringValue
	 *            the value to be tested
	 * @return true if the value of argument is valid for {@odf.datatype textEncoding} data type
	 *         false otherwise
	 */
	public static boolean isValid(String stringValue) {
		if ((stringValue == null) || (!textEncodingPattern.matcher(stringValue).matches())) {
			return false;
		} else {
			return true;
		}
	}
}