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package com.feilong.lib.digester3;

/*
 * 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.
 */

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.xml.sax.Attributes;

/**
 * 
 * Default implementation of the Rules interface that supports the standard rule matching behavior. This
 * class can also be used as a base class for specialized Rules implementations.
 * 
 * 
 * The matching policies implemented by this class support two different types of pattern matching rules:
 * 
 * 
 * Exact Match - A pattern "a/b/c" exactly matches a <c> element, nested inside a
 * <b> element, which is nested inside an <a> element.
 * Tail Match - A pattern "*/a/b" matches a <b> element, nested inside an
 * <a> element, no matter how deeply the pair is nested.
 * 
 * 
 * Note that wildcard patterns are ignored if an explicit match can be found (and when multiple wildcard patterns match,
 * only the longest, ie most explicit, pattern is considered a match).
 * 
 * 
 * See the package documentation for package org.apache.commons.digester3 for more information.
 * 
 */

public class RulesBase extends AbstractRulesImpl{

    // ----------------------------------------------------- Instance Variables

    /**
     * The set of registered Rule instances, keyed by the matching pattern. Each value is a List containing the Rules
     * for that pattern, in the order that they were orginally registered.
     */
    protected HashMap> cache = new HashMap<>();

    /**
     * The set of registered Rule instances, in the order that they were originally registered.
     */
    protected ArrayList             rules = new ArrayList<>();

    // ------------------------------------------------------------- Properties

    /**
     * {@inheritDoc}
     */
    @Override
    public void setDigester(Digester digester){
        super.setDigester(digester);
        for (Rule rule : rules){
            rule.setDigester(digester);
        }
    }

    // --------------------------------------------------------- Public Methods

    /**
     * {@inheritDoc}
     */
    @Override
    protected void registerRule(String pattern,Rule rule){
        // to help users who accidently add '/' to the end of their patterns
        int patternLength = pattern.length();
        if (patternLength > 1 && pattern.endsWith("/")){
            pattern = pattern.substring(0, patternLength - 1);
        }

        List list = cache.get(pattern);
        if (list == null){
            list = new ArrayList<>();
            cache.put(pattern, list);
        }
        list.add(rule);
        rules.add(rule);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void clear(){
        cache.clear();
        rules.clear();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List match(String namespaceURI,String pattern,String name,Attributes attributes){
        // List rulesList = (List) this.cache.get(pattern);
        List rulesList = lookup(namespaceURI, pattern);
        if ((rulesList == null) || (rulesList.size() < 1)){
            // Find the longest key, ie more discriminant
            String longKey = "";
            for (String key : cache.keySet()){
                if (key.startsWith("*/") && (pattern.equals(key.substring(2))
                                || pattern.endsWith(key.substring(1)) && key.length() > longKey.length())){
                    // rulesList = (List) this.cache.get(key);
                    rulesList = lookup(namespaceURI, key);
                    longKey = key;
                }
            }
        }
        if (rulesList == null){
            rulesList = new ArrayList<>();
        }
        return (rulesList);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List rules(){
        return (this.rules);
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Return a List of Rule instances for the specified pattern that also match the specified namespace URI (if any).
     * If there are no such rules, return null.
     *
     * @param namespaceURI
     *            Namespace URI to match, or null to select matching rules regardless of namespace
     *            URI
     * @param pattern
     *            Pattern to be matched
     * @return a List of Rule instances for the specified pattern that also match the specified namespace URI (if any)
     */
    protected List lookup(String namespaceURI,String pattern){
        // Optimize when no namespace URI is specified
        List list = this.cache.get(pattern);
        if (list == null){
            return (null);
        }
        if ((namespaceURI == null) || (namespaceURI.length() == 0)){
            return (list);
        }

        // Select only Rules that match on the specified namespace URI
        ArrayList results = new ArrayList<>();
        for (Rule item : list){
            if ((namespaceURI.equals(item.getNamespaceURI())) || (item.getNamespaceURI() == null)){
                results.add(item);
            }
        }
        return (results);
    }

}