001    /*
002     * Copyright (C) 2005 Joe Walnes.
003     * Copyright (C) 2006, 2007, 2008, 2009, 2013, 2014 XStream Committers.
004     * All rights reserved.
005     *
006     * The software in this package is published under the terms of the BSD
007     * style license a copy of which has been included with this distribution in
008     * the LICENSE.txt file.
009     * 
010     * Created on 09. April 2005 by Joe Walnes
011     */
012    package com.thoughtworks.xstream.mapper;
013    
014    import com.thoughtworks.xstream.core.util.FastField;
015    
016    import java.util.HashMap;
017    import java.util.HashSet;
018    import java.util.Iterator;
019    import java.util.LinkedHashSet;
020    import java.util.Map;
021    import java.util.Set;
022    import java.util.regex.Pattern;
023    
024    /**
025     * Mapper that allows a field of a specific class to be replaced with a shorter alias, or omitted
026     * entirely.
027     *
028     * @author Joe Walnes
029     */
030    public class FieldAliasingMapper extends MapperWrapper {
031    
032        protected final Map fieldToAliasMap = new HashMap();
033        protected final Map aliasToFieldMap = new HashMap();
034        protected final Set fieldsToOmit = new HashSet();
035        protected final Set unknownFieldsToIgnore = new LinkedHashSet();
036    
037        public FieldAliasingMapper(Mapper wrapped) {
038            super(wrapped);
039        }
040    
041        public void addFieldAlias(String alias, Class type, String fieldName) {
042            fieldToAliasMap.put(key(type, fieldName), alias);
043            aliasToFieldMap.put(key(type, alias), fieldName);
044        }
045        
046        public void addFieldsToIgnore(final Pattern pattern) {
047            unknownFieldsToIgnore.add(pattern);
048        }
049    
050        private Object key(Class type, String name) {
051            return new FastField(type, name);
052        }
053    
054        public String serializedMember(Class type, String memberName) {
055            String alias = getMember(type, memberName, fieldToAliasMap);
056            if (alias == null) {
057                return super.serializedMember(type, memberName);
058            } else {
059                return alias;
060            }
061        }
062    
063        public String realMember(Class type, String serialized) {
064            String real = getMember(type, serialized, aliasToFieldMap);
065            if (real == null) {
066                return super.realMember(type, serialized);
067            } else {
068                return real;
069            }
070        }
071    
072        private String getMember(Class type, String name, Map map) {
073            String member = null;
074            for (Class declaringType = type; 
075                    member == null && declaringType != Object.class && declaringType != null; 
076                    declaringType = declaringType.getSuperclass()) {
077                member = (String) map.get(key(declaringType, name));
078            }
079            return member;
080        }
081    
082        public boolean shouldSerializeMember(Class definedIn, String fieldName) {
083            if (fieldsToOmit.contains(key(definedIn, fieldName))) {
084                return false;
085            } else if (definedIn == Object.class && !unknownFieldsToIgnore.isEmpty()) {
086                for(Iterator iter = unknownFieldsToIgnore.iterator(); iter.hasNext();) {
087                    Pattern pattern = (Pattern)iter.next();
088                    if (pattern.matcher(fieldName).matches()) {
089                        return false;
090                    }
091                }
092            }
093            return true;
094        }
095    
096        public void omitField(Class definedIn, String fieldName) {
097            fieldsToOmit.add(key(definedIn, fieldName));
098        }
099    }