001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.beanutils.locale;
019
020import org.apache.commons.beanutils.ConversionException;
021import org.apache.commons.logging.Log;
022import org.apache.commons.logging.LogFactory;
023
024import java.text.ParseException;
025import java.util.Locale;
026
027
028/**
029 * <p>The base class for all standart type locale-sensitive converters.
030 * It has {@link LocaleConverter} and {@link org.apache.commons.beanutils.Converter} implementations,
031 * that convert an incoming locale-sensitive Object into an object of correspond type,
032 * optionally using a default value or throwing a {@link ConversionException}
033 * if a conversion error occurs.</p>
034 *
035 * @author Yauheny Mikulski
036 */
037
038public abstract class BaseLocaleConverter implements LocaleConverter {
039
040    // ----------------------------------------------------- Instance Variables
041
042    /** All logging goes through this logger */
043    private Log log = LogFactory.getLog(BaseLocaleConverter.class);
044
045    /** The default value specified to our Constructor, if any. */
046    private Object defaultValue = null;
047
048    /** Should we return the default value on conversion errors? */
049    protected boolean useDefault = false;
050
051    /** The locale specified to our Constructor, by default - system locale. */
052    protected Locale locale = Locale.getDefault();
053
054    /** The default pattern specified to our Constructor, if any. */
055    protected String pattern = null;
056
057    /** The flag indicating whether the given pattern string is localized or not. */
058    protected boolean locPattern = false;
059
060    // ----------------------------------------------------------- Constructors
061
062    /**
063     * Create a {@link LocaleConverter} that will throw a {@link ConversionException}
064     * if a conversion error occurs.
065     * An unlocalized pattern is used for the convertion.
066     *
067     * @param locale        The locale
068     * @param pattern       The convertion pattern
069     */
070    protected BaseLocaleConverter(Locale locale, String pattern) {
071
072        this(null, locale, pattern, false, false);
073    }
074
075    /**
076     * Create a {@link LocaleConverter} that will throw a {@link ConversionException}
077     * if a conversion error occurs.
078     *
079     * @param locale        The locale
080     * @param pattern       The convertion pattern
081     * @param locPattern    Indicate whether the pattern is localized or not
082     */
083    protected BaseLocaleConverter(Locale locale, String pattern, boolean locPattern) {
084
085        this(null, locale, pattern, false, locPattern);
086    }
087
088    /**
089     * Create a {@link LocaleConverter} that will return the specified default value
090     * if a conversion error occurs.
091     * An unlocalized pattern is used for the convertion.
092     *
093     * @param defaultValue  The default value to be returned
094     * @param locale        The locale
095     * @param pattern       The convertion pattern
096     */
097    protected BaseLocaleConverter(Object defaultValue, Locale locale, String pattern) {
098
099        this(defaultValue, locale, pattern, false);
100    }
101
102    /**
103     * Create a {@link LocaleConverter} that will return the specified default value
104     * if a conversion error occurs.
105     *
106     * @param defaultValue  The default value to be returned
107     * @param locale        The locale
108     * @param pattern       The convertion pattern
109     * @param locPattern    Indicate whether the pattern is localized or not
110     */
111    protected BaseLocaleConverter(Object defaultValue, Locale locale, String pattern, boolean locPattern) {
112
113        this(defaultValue, locale, pattern, true, locPattern);
114    }
115
116    /**
117     * Create a {@link LocaleConverter} that will return the specified default value
118     * or throw a {@link ConversionException} if a conversion error occurs.
119     *
120     * @param defaultValue  The default value to be returned
121     * @param locale        The locale
122     * @param pattern       The convertion pattern
123     * @param useDefault    Indicate whether the default value is used or not
124     * @param locPattern    Indicate whether the pattern is localized or not
125     */
126    private BaseLocaleConverter(Object defaultValue, Locale locale,
127                                String pattern, boolean useDefault, boolean locPattern) {
128
129        if (useDefault) {
130            this.defaultValue = defaultValue;
131            this.useDefault = true;
132        }
133
134        if (locale != null) {
135            this.locale = locale;
136        }
137
138        this.pattern = pattern;
139        this.locPattern = locPattern;
140    }
141
142    // --------------------------------------------------------- Methods
143
144    /**
145     * Convert the specified locale-sensitive input object into an output object of the
146     * specified type.
147     *
148     * @param value The input object to be converted
149     * @param pattern The pattern is used for the convertion
150     * @return The converted value
151     *
152     * @exception ParseException if conversion cannot be performed
153     *  successfully
154     */
155
156    abstract protected Object parse(Object value, String pattern) throws ParseException;
157
158
159    /**
160     * Convert the specified locale-sensitive input object into an output object.
161     * The default pattern is used for the convertion.
162     *
163     * @param value The input object to be converted
164     * @return The converted value
165     *
166     * @exception ConversionException if conversion cannot be performed
167     *  successfully
168     */
169    public Object convert(Object value) {
170        return convert(value, null);
171    }
172
173    /**
174     * Convert the specified locale-sensitive input object into an output object.
175     *
176     * @param value The input object to be converted
177     * @param pattern The pattern is used for the convertion
178     * @return The converted value
179     *
180     * @exception ConversionException if conversion cannot be performed
181     *  successfully
182     */
183    public Object convert(Object value, String pattern) {
184        return convert(null, value, pattern);
185    }
186
187    /**
188     * Convert the specified locale-sensitive input object into an output object of the
189     * specified type. The default pattern is used for the convertion.
190     *
191     * @param type Data type to which this value should be converted
192     * @param value The input object to be converted
193     * @return The converted value
194     *
195     * @exception ConversionException if conversion cannot be performed
196     *  successfully
197     */
198    public Object convert(Class type, Object value) {
199        return convert(type, value, null);
200    }
201
202    /**
203     * Convert the specified locale-sensitive input object into an output object of the
204     * specified type.
205     *
206     * @param type Data is type to which this value should be converted
207     * @param value is the input object to be converted
208     * @param pattern is the pattern is used for the conversion; if null is
209     * passed then the default pattern associated with the converter object
210     * will be used.
211     * @return The converted value
212     *
213     * @exception ConversionException if conversion cannot be performed
214     *  successfully
215     */
216    public Object convert(Class type, Object value, String pattern) {
217        if (value == null) {
218            if (useDefault) {
219                return (defaultValue);
220            } else {
221                // symmetric beanutils function allows null
222                // so do not: throw new ConversionException("No value specified");
223                log.debug("Null value specified for conversion, returing null");
224                return null;
225            }
226        }
227
228        try {
229            if (pattern != null) {
230                return parse(value, pattern);
231            } else {
232                return parse(value, this.pattern);
233            }
234        } catch (Exception e) {
235            if (useDefault) {
236                return (defaultValue);
237            } else {
238                if (e instanceof ConversionException) {
239                    throw (ConversionException)e;
240                }
241                throw new ConversionException(e);
242            }
243        }
244    }
245}