001    /*
002     *  Copyright 2004 The Apache Software Foundation
003     *
004     *  Licensed under the Apache License, Version 2.0 (the "License");
005     *  you may not use this file except in compliance with the License.
006     *  You may obtain a copy of the License at
007     *
008     *      http://www.apache.org/licenses/LICENSE-2.0
009     *
010     *  Unless required by applicable law or agreed to in writing, software
011     *  distributed under the License is distributed on an "AS IS" BASIS,
012     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     *  See the License for the specific language governing permissions and
014     *  limitations under the License.
015     */
016    package org.apache.commons.convert.conversion;
017    
018    import org.apache.commons.convert.Conversion;
019    import org.apache.commons.convert.ConversionFactory;
020    import org.apache.commons.convert.Converter;
021    
022    /**
023     * Conversion from TimeZone to String using <code>getID()</code>.
024     *
025     * @author Stephen Colebourne
026     * @version $Id: IdentityConversionFactory.java 155441 2005-02-26 13:19:22Z dirkv $
027     * @since 1.0
028     */
029    public class IdentityConversionFactory implements ConversionFactory {
030    
031        /** Singleton instance of this factory */
032        public static final ConversionFactory INSTANCE = new IdentityConversionFactory();
033    
034        /**
035         * Restricted constructor.
036         */
037        protected IdentityConversionFactory() {
038            super();
039        }
040    
041        //-----------------------------------------------------------------------
042        /**
043         * Checks if the types are equal, if so return 80.
044         * 
045         * @param value  the value to be converted, read only, may be null
046         * @param fromType  the type to convert from, may be null
047         * @param toType  the type to convert to, may be null
048         * @return 80 if types are equal
049         */
050        public int getMatchPercent(Object value, Class fromType, Class toType) {
051            if (fromType == toType && fromType != null) {
052                return 80;
053            }
054            return 0;
055        }
056    
057        /**
058         * Create a new conversion object for the specified from and to types.
059         * <p>
060         * This implementation returns the identity conversion.
061         *
062         * @param value  the value to be converted, read only, may be null
063         * @param fromType  the type to convert from, may be null
064         * @param toType  the type to convert to, may be null
065         * @return a Conversion object for repeatedly performing conversions
066         */
067        public Conversion getInstance(Object value, Class fromType, Class toType) {
068            return new IdentityConversion(fromType, toType);
069        }
070        
071        /**
072         * Gets a string suitable for debugging.
073         * 
074         * @return a debugging string
075         */
076        public String toString() {
077            return "ConversionFactory[Identity]";
078        }
079    
080        //-----------------------------------------------------------------------
081        /**
082         * Generic conversion implementation that returns the input value.
083         */
084        class IdentityConversion extends AbstractConversion {
085    
086            /**
087             * Constructs a Conversion.
088             * 
089             * @param fromType  the type to convert from
090             * @param toType  the type to convert to
091             */
092            IdentityConversion(Class fromType, Class toType) {
093                super(fromType, toType);
094            }
095    
096            /**
097             * Converts the input value by returning it unchanged.
098             * 
099             * @param value  the input value to be converted, pre-checked to not be null
100             * @param converter  the converter being used, not null
101             * @return the input value
102             */
103            public Object convert(Object value, Converter converter) {
104                return value;
105            }
106        }
107    
108    }