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 java.text.ParseException; 021import java.util.Locale; 022 023import org.apache.commons.beanutils.ConversionException; 024import org.apache.commons.beanutils.ConvertUtils; 025import org.apache.commons.logging.Log; 026import org.apache.commons.logging.LogFactory; 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 */ 036 037public abstract class BaseLocaleConverter implements LocaleConverter { 038 039 /** 040 * Checks whether the result of a conversion is conform to the specified 041 * target type. If this is the case, the passed in result object is cast to 042 * the correct target type. Otherwise, an exception is thrown. 043 * 044 * @param <T> the desired result type 045 * @param type the target class of the conversion 046 * @param result the conversion result object 047 * @return the result cast to the target class 048 * @throws ConversionException if the result object is not compatible with 049 * the target type 050 */ 051 private static <T> T checkConversionResult(final Class<T> type, final Object result) { 052 if (type == null) { 053 // in this case we cannot do much; the result object is returned 054 @SuppressWarnings("unchecked") 055 final 056 T temp = (T) result; 057 return temp; 058 } 059 060 if (result == null) { 061 return null; 062 } 063 if (type.isInstance(result)) { 064 return type.cast(result); 065 } 066 throw new ConversionException("Unsupported target type: " + type); 067 } 068 069 /** All logging goes through this logger */ 070 private final Log log = LogFactory.getLog(BaseLocaleConverter.class); 071 072 /** The default value specified to our Constructor, if any. */ 073 private Object defaultValue; 074 075 /** Should we return the default value on conversion errors? */ 076 protected boolean useDefault; 077 078 /** The locale specified to our Constructor, by default - system locale. */ 079 protected Locale locale = Locale.getDefault(); 080 081 /** The default pattern specified to our Constructor, if any. */ 082 protected String pattern; 083 084 /** The flag indicating whether the given pattern string is localized or not. */ 085 protected boolean locPattern; 086 087 /** 088 * Create a {@link LocaleConverter} that will throw a {@link ConversionException} 089 * if a conversion error occurs. 090 * An unlocalized pattern is used for the convertion. 091 * 092 * @param locale The locale 093 * @param pattern The convertion pattern 094 */ 095 protected BaseLocaleConverter(final Locale locale, final String pattern) { 096 097 this(null, locale, pattern, false, false); 098 } 099 100 /** 101 * Create a {@link LocaleConverter} that will throw a {@link ConversionException} 102 * if a conversion error occurs. 103 * 104 * @param locale The locale 105 * @param pattern The convertion pattern 106 * @param locPattern Indicate whether the pattern is localized or not 107 */ 108 protected BaseLocaleConverter(final Locale locale, final String pattern, final boolean locPattern) { 109 110 this(null, locale, pattern, false, locPattern); 111 } 112 113 /** 114 * Create a {@link LocaleConverter} that will return the specified default value 115 * if a conversion error occurs. 116 * An unlocalized pattern is used for the convertion. 117 * 118 * @param defaultValue The default value to be returned 119 * @param locale The locale 120 * @param pattern The convertion pattern 121 */ 122 protected BaseLocaleConverter(final Object defaultValue, final Locale locale, final String pattern) { 123 124 this(defaultValue, locale, pattern, false); 125 } 126 127 /** 128 * Create a {@link LocaleConverter} that will return the specified default value 129 * if a conversion error occurs. 130 * 131 * @param defaultValue The default value to be returned 132 * @param locale The locale 133 * @param pattern The convertion pattern 134 * @param locPattern Indicate whether the pattern is localized or not 135 */ 136 protected BaseLocaleConverter(final Object defaultValue, final Locale locale, final String pattern, final boolean locPattern) { 137 138 this(defaultValue, locale, pattern, true, locPattern); 139 } 140 141 /** 142 * Create a {@link LocaleConverter} that will return the specified default value 143 * or throw a {@link ConversionException} if a conversion error occurs. 144 * 145 * @param defaultValue The default value to be returned 146 * @param locale The locale 147 * @param pattern The convertion pattern 148 * @param useDefault Indicate whether the default value is used or not 149 * @param locPattern Indicate whether the pattern is localized or not 150 */ 151 private BaseLocaleConverter(final Object defaultValue, final Locale locale, 152 final String pattern, final boolean useDefault, final boolean locPattern) { 153 154 if (useDefault) { 155 this.defaultValue = defaultValue; 156 this.useDefault = true; 157 } 158 159 if (locale != null) { 160 this.locale = locale; 161 } 162 163 this.pattern = pattern; 164 this.locPattern = locPattern; 165 } 166 167 /** 168 * Convert the specified locale-sensitive input object into an output object of the 169 * specified type. The default pattern is used for the convertion. 170 * 171 * @param <T> The desired target type of the conversion 172 * @param type Data type to which this value should be converted 173 * @param value The input object to be converted 174 * @return The converted value 175 * @throws ConversionException if conversion cannot be performed 176 * successfully 177 */ 178 @Override 179 public <T> T convert(final Class<T> type, final Object value) { 180 return convert(type, value, null); 181 } 182 183 /** 184 * Convert the specified locale-sensitive input object into an output object of the 185 * specified type. 186 * 187 * @param <T> The desired target type of the conversion 188 * @param type Data is type to which this value should be converted 189 * @param value is the input object to be converted 190 * @param pattern is the pattern is used for the conversion; if null is 191 * passed then the default pattern associated with the converter object 192 * will be used. 193 * @return The converted value 194 * @throws ConversionException if conversion cannot be performed 195 * successfully 196 */ 197 @Override 198 public <T> T convert(final Class<T> type, final Object value, final String pattern) { 199 final Class<T> targetType = ConvertUtils.primitiveToWrapper(type); 200 if (value == null) { 201 if (useDefault) { 202 return getDefaultAs(targetType); 203 } 204 // symmetric beanutils function allows null 205 // so do not: throw new ConversionException("No value specified"); 206 log.debug("Null value specified for conversion, returing null"); 207 return null; 208 } 209 210 try { 211 if (pattern != null) { 212 return checkConversionResult(targetType, parse(value, pattern)); 213 } 214 return checkConversionResult(targetType, parse(value, this.pattern)); 215 } catch (final Exception e) { 216 if (useDefault) { 217 return getDefaultAs(targetType); 218 } 219 if (e instanceof ConversionException) { 220 throw (ConversionException)e; 221 } 222 throw new ConversionException(e); 223 } 224 } 225 226 /** 227 * Convert the specified locale-sensitive input object into an output object. 228 * The default pattern is used for the conversion. 229 * 230 * @param value The input object to be converted 231 * @return The converted value 232 * @throws ConversionException if conversion cannot be performed 233 * successfully 234 */ 235 public Object convert(final Object value) { 236 return convert(value, null); 237 } 238 239 /** 240 * Convert the specified locale-sensitive input object into an output object. 241 * 242 * @param value The input object to be converted 243 * @param pattern The pattern is used for the conversion 244 * @return The converted value 245 * @throws ConversionException if conversion cannot be performed 246 * successfully 247 */ 248 public Object convert(final Object value, final String pattern) { 249 return convert(null, value, pattern); 250 } 251 252 /** 253 * Returns the default object specified for this converter cast for the 254 * given target type. If the default value is not conform to the given type, 255 * an exception is thrown. 256 * 257 * @param <T> the desired target type 258 * @param type the target class of the conversion 259 * @return the default value in the given target type 260 * @throws ConversionException if the default object is not compatible with 261 * the target type 262 */ 263 private <T> T getDefaultAs(final Class<T> type) { 264 return checkConversionResult(type, defaultValue); 265 } 266 267 /** 268 * Convert the specified locale-sensitive input object into an output object of the 269 * specified type. 270 * 271 * @param value The input object to be converted 272 * @param pattern The pattern is used for the convertion 273 * @return The converted value 274 * @throws ParseException if conversion cannot be performed 275 * successfully 276 */ 277 278 abstract protected Object parse(Object value, String pattern) throws ParseException; 279}