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 *   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,
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 *  specific language governing permissions and limitations
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package org.apache.cayenne.util;

import java.util.StringTokenizer;

/** 
 * Utility class to convert from different naming styles to Java convention.
 * For example names like "ABCD_EFG" can be converted to "abcdEfg".
 * 
 * @author Andrei Adamchik
 */
public class NameConverter {

    /**
     * Converts a String name to a String forllowing java convention for the 
     * static final variables. E.g. "abcXyz" will be converted to "ABC_XYZ".
     * 
     * @since 1.0.3
     */
    public static String javaToUnderscored(String name) {
        if (name == null) {
            return null;
        }

        char charArray[] = name.toCharArray();
        StringBuffer buffer = new StringBuffer();

        for (int i = 0; i < charArray.length; i++) {
            if ((Character.isUpperCase(charArray[i])) && (i != 0)) {
                
                char prevChar = charArray[i - 1];
                if ((Character.isLowerCase(prevChar))) {
                    buffer.append("_");
                }
            }

            buffer.append(Character.toUpperCase(charArray[i]));
        }

        return buffer.toString();
    }

    /**
     * @deprecated since 1.2 replaced with {@link #underscoredToJava(String, boolean)},
     *             fixing the naming typo.
     */
    public static String undescoredToJava(String name, boolean capitalize) {
        return underscoredToJava(name, capitalize);
    }
    
    /** 
     * Converts names like "ABCD_EFG_123" to Java-style names like "abcdEfg123".
     * If capitalize is true, returned name is capitalized
     * (for instance if this is a class name).
     * 
     *  @since 1.2
     */
    public static String underscoredToJava(String name, boolean capitalize) {
        StringTokenizer st = new StringTokenizer(name, "_");
        StringBuffer buf = new StringBuffer();

        boolean first = true;
        while (st.hasMoreTokens()) {
            String token = st.nextToken();

            int len = token.length();
            if (len == 0) {
                continue;
            }

            // sniff mixed case vs. single case styles
            boolean hasLowerCase = false;
            boolean hasUpperCase = false;
            for (int i = 0; i < len && !(hasUpperCase && hasLowerCase); i++) {
                if (Character.isUpperCase(token.charAt(i))) {
                    hasUpperCase = true;
                } else if (Character.isLowerCase(token.charAt(i))) {
                    hasLowerCase = true;
                }
            }

            // if mixed case, preserve it, if all upper, convert to lower
            if (hasUpperCase && !hasLowerCase) {
                token = token.toLowerCase();
            }

            if (first) {
                // apply explicit capitalization rules, if this is the first token
                first = false;
                if (capitalize) {
                    buf.append(Character.toUpperCase(token.charAt(0)));
                } else {
                    buf.append(Character.toLowerCase(token.charAt(0)));
                }
            } else {
                buf.append(Character.toUpperCase(token.charAt(0)));
            }

            if (len > 1) {
                buf.append(token.substring(1, len));
            }
        }
        return buf.toString();
    }
}