org.springframework.util.Pluralizer.java Source code

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Here is the source code for org.springframework.util.Pluralizer.java

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/*
 * Copyright 2002-2005 the original author or authors.
 *
 * 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 org.springframework.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * @author Rob Harrop
 * @since 2.0
 */
public abstract class Pluralizer {

    private static final Log logger = LogFactory.getLog(Pluralizer.class);

    private static List pluralizationRules = Collections.synchronizedList(new ArrayList());

    private static Map pluralizationCache = Collections.synchronizedMap(new HashMap());

    static {
        // register default rules

        // y -> ies
        registerPluralizationRule(new RegexPluralizationRule("([^aeiouy])y$", "ies", 1));

        // sxz -> [sxz]es
        registerPluralizationRule(new RegexPluralizationRule("([sxz])$", "es", 1));

        // hard h -> hes
        registerPluralizationRule(new RegexPluralizationRule("([^aeioudgkprt]h$)", "es", 1));
    }

    public static String pluralize(String term) {

        String pluralForm = (String) pluralizationCache.get(term);

        if (pluralForm == null) {
            PluralizationRule rule = lookupPluralizationRule(term);

            if (rule != null) {
                pluralForm = rule.apply(term);
            } else {
                pluralForm = applyDefaultRule(term);

                if (logger.isDebugEnabled()) {
                    logger.debug("Located pluralization [" + pluralForm + "] for term [" + term
                            + "] using default rules.");
                }
            }
        } else {
            if (logger.isDebugEnabled()) {
                logger.debug("Located pluralization [" + pluralForm + "] for term [" + term + "] in the cache.");
            }
        }

        return pluralForm;
    }

    public static void registerPluralizationRule(PluralizationRule rule) {
        pluralizationRules.add(rule);
    }

    /**
     * Attempts to locate and return a {@link PluralizationRule} for the specified term using the
     * set of configured {@link PluralizationRule PluralizationRules}. Returns <code>null</code>
     * if no rule can be found.
     */
    private static PluralizationRule lookupPluralizationRule(String term) {
        for (int i = 0; i < pluralizationRules.size(); i++) {
            PluralizationRule rule = (PluralizationRule) pluralizationRules.get(i);
            if (rule.appliesTo(term)) {
                return rule;
            }
        }

        return null;
    }

    /**
     * Applies default English pluralization rules adding &quot;s&quot; to the end of the term.
     */
    private static String applyDefaultRule(String term) {
        return term + "s";
    }

    public static interface PluralizationRule {

        boolean appliesTo(String term);

        String apply(String term);
    }

    private static class RegexPluralizationRule implements PluralizationRule {

        private Pattern pattern;

        private String replacement;

        private int includeGroup = -1;

        public RegexPluralizationRule(String pattern, String replacement) {
            this(pattern, replacement, -1);
        }

        public RegexPluralizationRule(String pattern, String replacement, int includeGroup) {
            this.pattern = Pattern.compile(pattern);
            this.replacement = replacement;
            this.includeGroup = includeGroup;
        }

        public boolean appliesTo(String term) {
            return pattern.matcher(term).find();
        }

        public String apply(String term) {
            Matcher m = pattern.matcher(term);
            if (m.find()) {
                String replace = (this.includeGroup > -1) ? m.group(this.includeGroup) : "";
                replace += this.replacement;
                return m.replaceFirst(replace);
            } else {
                return term;
            }
        }
    }

    public static void main(String[] args) {
        Pattern p = Pattern.compile("([^aeiouy]|qu)y$");
        Matcher m = p.matcher("ability");
        if (m.find()) {
            System.out.println(m.replaceFirst("\\1ies"));
        }
    }
}