extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/TokenName.java

/*
 * 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.apache.guacamole.auth.ldap;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class for generating parameter token names.
 */
public class TokenName {

    /**
     * The prefix string to add to each parameter token generated from an LDAP
     * attribute name.
     */
    private static final String LDAP_ATTRIBUTE_TOKEN_PREFIX = "LDAP_";

    /**
     * Pattern which matches logical groupings of words within an LDAP
     * attribute name. This pattern is intended to match logical groupings
     * regardless of the naming convention used: "CamelCase",
     * "headlessCamelCase", "lowercase_with_underscores",
     * "lowercase-with-dashes" or even "aVery-INCONSISTENTMix_ofAllStyles".
     */
    private static final Pattern LDAP_ATTRIBUTE_NAME_GROUPING = Pattern.compile(

        // "Camel" word groups
        "\\p{javaUpperCase}\\p{javaLowerCase}+"

        // Groups of digits
        + "|[0-9]+"

        // Groups of uppercase letters, excluding the uppercase letter
        // which begins a following "Camel" group
        + "|\\p{javaUpperCase}+(?!\\p{javaLowerCase})"

        // Groups of lowercase letters which match no other pattern
        + "|\\p{javaLowerCase}+"

        // Groups of word characters letters which match no other pattern
        + "|\\b\\w+\\b"

    );

    /**
     * This utility class should not be instantiated.
     */
    private TokenName() {}

    /**
     * Generates the name of the parameter token that should be populated with
     * the value of the given LDAP attribute. The name of the LDAP attribute
     * will automatically be transformed from "CamelCase", "headlessCamelCase",
     * "lowercase_with_underscores", and "mixes_ofBoth_Styles" to consistent
     * "UPPERCASE_WITH_UNDERSCORES". Each returned attribute will be prefixed
     * with "LDAP_".
     *
     * @param name
     *     The name of the LDAP attribute to use to generate the token name.
     *
     * @return
     *     The name of the parameter token that should be populated with the
     *     value of the LDAP attribute having the given name.
     */
    public static String fromAttribute(String name) {

        // If even one logical word grouping cannot be found, default to
        // simply converting the attribute to uppercase and adding the
        // prefix
        Matcher groupMatcher = LDAP_ATTRIBUTE_NAME_GROUPING.matcher(name);
        if (!groupMatcher.find())
            return LDAP_ATTRIBUTE_TOKEN_PREFIX + name.toUpperCase();

        // Split the given name into logical word groups, separated by
        // underscores and converted to uppercase
        StringBuilder builder = new StringBuilder(LDAP_ATTRIBUTE_TOKEN_PREFIX);
        builder.append(groupMatcher.group(0).toUpperCase());

        while (groupMatcher.find()) {
            builder.append("_");
            builder.append(groupMatcher.group(0).toUpperCase());
        }

        return builder.toString();

    }

}