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OAuth 2.0 SDK with OpenID Connection extensions for developing client and server applications.
There is a newer version: 11.19.1
/*
 * oauth2-oidc-sdk
 *
 * Copyright 2012-2016, Connect2id Ltd and contributors.
 *
 * Licensed 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 com.nimbusds.oauth2.sdk.device;


import net.jcip.annotations.Immutable;

import com.nimbusds.oauth2.sdk.id.Identifier;
import com.nimbusds.oauth2.sdk.util.StringUtils;


/**
 * User code.
 *
 * Related specifications:
 *
 * 

 *     OAuth 2.0 Device Authorization Grant (draft-ietf-oauth-device-flow-15)
 * 
 */
@Immutable
public final class UserCode extends Identifier {

	
	public static final String LETTER_CHAR_SET = "BCDFGHJKLMNPQRSTVWXZ";


	public static final String DIGIT_CHAR_SET = "0123456789";


	/**
	 * The character set used by the identifier. The identifier can only
	 * contain characters from this set.
	 */
	private final String charset;


	/**
	 * Creates a new user code with the specified value.
	 *
	 * @param value   The code value. Must not be {@code null} or empty
	 *                string.
	 * @param charset The character set used by the identifier. The
	 *                identifier can only contain characters from this set.
	 *                If {@code null}, all characters are allowed.
	 */
	public UserCode(final String value, final String charset) {

		super(value);

		this.charset = charset;
	}


	/**
	 * Creates a new user code with the specified value and the
	 * {@code LETTER_CHAR_SET}.
	 *
	 * @param value The code value. Must not be {@code null} or empty
	 *              string.
	 */
	public UserCode(final String value) {

		this(value, LETTER_CHAR_SET);
	}


	/**
	 * Creates a new user code with a randomly generated value with 8
	 * characters from {@code LETTER_CHAR_SET}, in the form
	 * {@code WDJB-MJHT}.
	 */
	public UserCode() {

		this(LETTER_CHAR_SET, 8);
	}


	/**
	 * Creates a new user code with a randomly generated value from the
	 * specified charset and length. A dash is added every 4 characters.
	 */
	public UserCode(final String charset, final int length) {

		this(generateValue(charset, length), charset);
	}


	/**
	 * Creates a new user code with a randomly generated value from the
	 * specified charset and length. A dash is added every 4 characters.
	 * 
	 * @param charset The character set used by the identifier. The
	 *                identifier can only contain characters from this set.
	 *                Must not be {@code null} or empty string.
	 * @param length  The length of the value to generate.
	 */
	private static String generateValue(final String charset, final int length) {

		if (StringUtils.isBlank(charset))
			throw new IllegalArgumentException("The charset must not be null or empty string");

		StringBuilder value = new StringBuilder();
		for (int index = 0; index < length; index++) {
			if (index > 0 && index % 4 == 0)
				value.append('-');
			value.append(charset.charAt(secureRandom.nextInt(charset.length())));
		}
		return value.toString();
	}


	/**
	 * Returns the character set used by this {@code UserCode}.
	 * 
	 * @return The character set, or {@code null} if unspecified.
	 */
	public String getCharset() {

		return charset;
	}


	/**
	 * Returns the value with all invalid characters removed.
	 * 
	 * @return The value with all invalid characters removed.
	 */
	public String getStrippedValue() {

		return stripIllegalChars(getValue(), getCharset());
	}


	@Override
	public int compareTo(final Identifier other) {

		// fallback to default compare for other identifiers
		if (!(other instanceof UserCode))
			return super.compareTo(other);

		return getStrippedValue().compareTo(((UserCode) other).getStrippedValue());
	}


	@Override
	public int hashCode() {

		return getStrippedValue() != null ? getStrippedValue().hashCode() : 0;
	}


	@Override
	public boolean equals(final Object object) {

		return object instanceof UserCode
		                && this.getStrippedValue().equals(((UserCode) object).getStrippedValue());
	}


	/**
	 * Removes all characters from {@code value} that are not in
	 * {@code charset}.
	 * 
	 * @param value   The code value.
	 * @param charset The allowed characters in {@code value}. If
	 *                {@code null} all characters are retained.
	 * @return The {@code value} with all invalid characters removed.
	 */
	public static String stripIllegalChars(final String value, final String charset) {

		if (charset == null)
			return value.toUpperCase();

		StringBuilder newValue = new StringBuilder();
		for (char curChar : value.toUpperCase().toCharArray()) {
			if (charset.indexOf(curChar) >= 0)
				newValue.append(curChar);
		}
		return newValue.toString();
	}
}