org.apache.commons.beanutils.locale.BaseLocaleConverter Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.commons.beanutils.locale;
import java.text.ParseException;
import java.util.Locale;
import org.apache.commons.beanutils.ConversionException;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* The base class for all standart type locale-sensitive converters.
* It has {@link LocaleConverter} and {@link org.apache.commons.beanutils.Converter} implementations,
* that convert an incoming locale-sensitive Object into an object of correspond type,
* optionally using a default value or throwing a {@link ConversionException}
* if a conversion error occurs.
*
* @version $Id: BaseLocaleConverter.java 1747095 2016-06-07 00:27:52Z ggregory $
*/
public abstract class BaseLocaleConverter implements LocaleConverter {
// ----------------------------------------------------- Instance Variables
/** All logging goes through this logger */
private final Log log = LogFactory.getLog(BaseLocaleConverter.class);
/** The default value specified to our Constructor, if any. */
private Object defaultValue = null;
/** Should we return the default value on conversion errors? */
protected boolean useDefault = false;
/** The locale specified to our Constructor, by default - system locale. */
protected Locale locale = Locale.getDefault();
/** The default pattern specified to our Constructor, if any. */
protected String pattern = null;
/** The flag indicating whether the given pattern string is localized or not. */
protected boolean locPattern = false;
// ----------------------------------------------------------- Constructors
/**
* Create a {@link LocaleConverter} that will throw a {@link ConversionException}
* if a conversion error occurs.
* An unlocalized pattern is used for the convertion.
*
* @param locale The locale
* @param pattern The convertion pattern
*/
protected BaseLocaleConverter(final Locale locale, final String pattern) {
this(null, locale, pattern, false, false);
}
/**
* Create a {@link LocaleConverter} that will throw a {@link ConversionException}
* if a conversion error occurs.
*
* @param locale The locale
* @param pattern The convertion pattern
* @param locPattern Indicate whether the pattern is localized or not
*/
protected BaseLocaleConverter(final Locale locale, final String pattern, final boolean locPattern) {
this(null, locale, pattern, false, locPattern);
}
/**
* Create a {@link LocaleConverter} that will return the specified default value
* if a conversion error occurs.
* An unlocalized pattern is used for the convertion.
*
* @param defaultValue The default value to be returned
* @param locale The locale
* @param pattern The convertion pattern
*/
protected BaseLocaleConverter(final Object defaultValue, final Locale locale, final String pattern) {
this(defaultValue, locale, pattern, false);
}
/**
* Create a {@link LocaleConverter} that will return the specified default value
* if a conversion error occurs.
*
* @param defaultValue The default value to be returned
* @param locale The locale
* @param pattern The convertion pattern
* @param locPattern Indicate whether the pattern is localized or not
*/
protected BaseLocaleConverter(final Object defaultValue, final Locale locale, final String pattern, final boolean locPattern) {
this(defaultValue, locale, pattern, true, locPattern);
}
/**
* Create a {@link LocaleConverter} that will return the specified default value
* or throw a {@link ConversionException} if a conversion error occurs.
*
* @param defaultValue The default value to be returned
* @param locale The locale
* @param pattern The convertion pattern
* @param useDefault Indicate whether the default value is used or not
* @param locPattern Indicate whether the pattern is localized or not
*/
private BaseLocaleConverter(final Object defaultValue, final Locale locale,
final String pattern, final boolean useDefault, final boolean locPattern) {
if (useDefault) {
this.defaultValue = defaultValue;
this.useDefault = true;
}
if (locale != null) {
this.locale = locale;
}
this.pattern = pattern;
this.locPattern = locPattern;
}
// --------------------------------------------------------- Methods
/**
* Convert the specified locale-sensitive input object into an output object of the
* specified type.
*
* @param value The input object to be converted
* @param pattern The pattern is used for the convertion
* @return The converted value
*
* @throws ParseException if conversion cannot be performed
* successfully
*/
abstract protected Object parse(Object value, String pattern) throws ParseException;
/**
* Convert the specified locale-sensitive input object into an output object.
* The default pattern is used for the conversion.
*
* @param value The input object to be converted
* @return The converted value
*
* @throws ConversionException if conversion cannot be performed
* successfully
*/
public Object convert(final Object value) {
return convert(value, null);
}
/**
* Convert the specified locale-sensitive input object into an output object.
*
* @param value The input object to be converted
* @param pattern The pattern is used for the conversion
* @return The converted value
*
* @throws ConversionException if conversion cannot be performed
* successfully
*/
public Object convert(final Object value, final String pattern) {
return convert(null, value, pattern);
}
/**
* Convert the specified locale-sensitive input object into an output object of the
* specified type. The default pattern is used for the convertion.
*
* @param The desired target type of the conversion
* @param type Data type to which this value should be converted
* @param value The input object to be converted
* @return The converted value
*
* @throws ConversionException if conversion cannot be performed
* successfully
*/
public T convert(final Class type, final Object value) {
return convert(type, value, null);
}
/**
* Convert the specified locale-sensitive input object into an output object of the
* specified type.
*
* @param The desired target type of the conversion
* @param type Data is type to which this value should be converted
* @param value is the input object to be converted
* @param pattern is the pattern is used for the conversion; if null is
* passed then the default pattern associated with the converter object
* will be used.
* @return The converted value
*
* @throws ConversionException if conversion cannot be performed
* successfully
*/
public T convert(final Class type, final Object value, final String pattern) {
final Class targetType = ConvertUtils.primitiveToWrapper(type);
if (value == null) {
if (useDefault) {
return getDefaultAs(targetType);
} else {
// symmetric beanutils function allows null
// so do not: throw new ConversionException("No value specified");
log.debug("Null value specified for conversion, returing null");
return null;
}
}
try {
if (pattern != null) {
return checkConversionResult(targetType, parse(value, pattern));
} else {
return checkConversionResult(targetType, parse(value, this.pattern));
}
} catch (final Exception e) {
if (useDefault) {
return getDefaultAs(targetType);
} else {
if (e instanceof ConversionException) {
throw (ConversionException)e;
}
throw new ConversionException(e);
}
}
}
/**
* Returns the default object specified for this converter cast for the
* given target type. If the default value is not conform to the given type,
* an exception is thrown.
*
* @param the desired target type
* @param type the target class of the conversion
* @return the default value in the given target type
* @throws ConversionException if the default object is not compatible with
* the target type
*/
private T getDefaultAs(final Class type) {
return checkConversionResult(type, defaultValue);
}
/**
* Checks whether the result of a conversion is conform to the specified
* target type. If this is the case, the passed in result object is cast to
* the correct target type. Otherwise, an exception is thrown.
*
* @param the desired result type
* @param type the target class of the conversion
* @param result the conversion result object
* @return the result cast to the target class
* @throws ConversionException if the result object is not compatible with
* the target type
*/
private static T checkConversionResult(final Class type, final Object result) {
if (type == null) {
// in this case we cannot do much; the result object is returned
@SuppressWarnings("unchecked")
final
T temp = (T) result;
return temp;
}
if (result == null) {
return null;
}
if (type.isInstance(result)) {
return type.cast(result);
}
throw new ConversionException("Unsupported target type: " + type);
}
}