net.hasor.utils.convert.ConverterBean Maven / Gradle / Ivy
The newest version!
/*
* 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 net.hasor.utils.convert;
import net.hasor.utils.convert.convert.*;
import net.hasor.utils.supplier.ContextClassLoaderLocal;
import java.io.File;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.URI;
import java.net.URL;
import java.sql.Timestamp;
import java.util.Calendar;
import java.util.Collection;
/**
* Utility methods for converting String scalar values to objects of the
* specified Class, String arrays to arrays of the specified Class. The
* actual {@link Converter} instance to be used can be registered for each
* possible destination Class. Unless you override them, standard
* {@link Converter} instances are provided for all of the following
* destination Classes:
*
* - java.lang.BigDecimal (no default value)
* - java.lang.BigInteger (no default value)
* - boolean and java.lang.Boolean (default to false)
* - byte and java.lang.Byte (default to zero)
* - char and java.lang.Character (default to a space)
* - java.lang.Class (no default value)
* - double and java.lang.Double (default to zero)
* - float and java.lang.Float (default to zero)
* - int and java.lang.Integer (default to zero)
* - long and java.lang.Long (default to zero)
* - short and java.lang.Short (default to zero)
* - java.lang.String (default to null)
* - java.io.File (no default value)
* - java.net.URL (no default value)
* - java.sql.Date (no default value)
* - java.sql.Time (no default value)
* - java.sql.Timestamp (no default value)
*
*
* For backwards compatibility, the standard Converters for primitive
* types (and the corresponding wrapper classes) return a defined
* default value when a conversion error occurs. If you prefer to have a
* {@link ConversionException} thrown instead, replace the standard Converter
* instances with instances created with the zero-arguments constructor. For
* example, to cause the Converters for integers to throw an exception on
* conversion errors, you could do this:
*
* // No-args constructor gets the version that throws exceptions
* Converter myConverter = new net.hasor.utils.convert.convert.IntegerConverter();
* ConverterUtils.register(myConverter, Integer.TYPE); // Native type
* ConverterUtils.register(myConverter, Integer.class); // Wrapper class
*
*
*
* Converters generally treat null input as if it were invalid
* input, ie they return their default value if one was specified when the
* converter was constructed, and throw an exception otherwise. If you prefer
* nulls to be preserved for converters that are converting to objects (not
* primitives) then register a converter as above, passing a default value of
* null to the converter constructor (and of course registering that converter
* only for the .class target).
*
*
*
* When a converter is listed above as having no default value, then that
* converter will throw an exception when passed null or an invalid value
* as its input. In particular, by default the BigInteger and BigDecimal
* converters have no default (and are therefore somewhat inconsistent
* with the other numerical converters which all have zero as their default).
*
*
*
* Converters that generate arrays of each of the primitive types are
* also automatically configured (including String[]). When passed null
* or invalid input, these return an empty array (not null). See class
* AbstractArrayConverter for the supported input formats for these converters.
*
*
* @author Craig R. McClanahan
* @author Ralph Schaer
* @author Chris Audley
* @author James Strachan
* @version $Revision: 745079 $ $Date: 2009-02-17 14:04:10 +0000 (Tue, 17 Feb 2009) $
* @since 1.7
*/
public class ConverterBean {
private static final Integer ZERO = 0;
private static final Character SPACE = ' ';
/** Contains ConverterBean instances indexed by context classloader. */
private static final ConverterBeanContextClassLoaderLocal BEANS_BY_CLASSLOADER = new ConverterBeanContextClassLoaderLocal();
private static class ConverterBeanContextClassLoaderLocal extends ContextClassLoaderLocal {
@Override
protected ConverterBean initialValue() {
return new ConverterBean();
}
}
// ------------------------------------------------------- Class Methods
/**
* Get singleton instance
* @return The singleton instance
*/
protected static ConverterBean getInstance() {
return ConverterBean.BEANS_BY_CLASSLOADER.get();
}
// ------------------------------------------------------- Variables
/**
* The set of {@link Converter}s that can be used to convert Strings
* into objects of a specified Class, keyed by the destination Class.
*/
private WeakFastHashMap converters = new WeakFastHashMap();
// ------------------------------------------------------- Constructors
/** Construct a bean with standard converters registered */
public ConverterBean() {
this.converters.setFast(false);
this.deregister();
this.converters.setFast(true);
}
// --------------------------------------------------------- Public Methods
/**
* Convert the specified value into a String. If the specified value
* is an array, the first element (converted to a String) will be
* returned. The registered {@link Converter} for the
* java.lang.String class will be used, which allows
* applications to customize Object->String conversions (the default
* implementation simply uses toString()).
*
* @param value Value to be converted (may be null)
* @return The converted String value
*/
public String convert(Object value) {
if (value == null) {
return null;
} else if (value.getClass().isArray()) {
if (Array.getLength(value) < 1) {
return null;
}
value = Array.get(value, 0);
if (value == null) {
return null;
} else {
Converter converter = this.lookup(String.class);
return (String) converter.convert(String.class, value);
}
} else {
Converter converter = this.lookup(String.class);
return (String) converter.convert(String.class, value);
}
}
/**
* Convert the specified value to an object of the specified class (if
* possible). Otherwise, return a String representation of the value.
*
* @param value Value to be converted (may be null)
* @param clazz Java class to be converted to
* @return The converted value
*
* @exception ConversionException if thrown by an underlying Converter
*/
public Object convert(final String value, final Class clazz) {
Converter converter = this.lookup(clazz);
if (converter == null) {
converter = this.lookup(String.class);
}
return converter.convert(clazz, value);
}
/**
* Convert an array of specified values to an array of objects of the
* specified class (if possible). If the specified Java class is itself
* an array class, this class will be the type of the returned value.
* Otherwise, an array will be constructed whose component type is the
* specified class.
*
* @param values Array of values to be converted
* @param clazz Java array or element class to be converted to
* @return The converted value
*
* @exception ConversionException if thrown by an underlying Converter
*/
public Object convert(final String[] values, final Class clazz) {
Class type = clazz;
if (clazz.isArray()) {
type = clazz.getComponentType();
}
Converter converter = this.lookup(type);
if (converter == null) {
converter = this.lookup(String.class);
}
Object array = Array.newInstance(type, values.length);
for (int i = 0; i < values.length; i++) {
Array.set(array, i, converter.convert(type, values[i]));
}
return array;
}
/**
* Convert the value to an object of the specified class (if
* possible).
*
* @param value Value to be converted (may be null)
* @param targetType Class of the value to be converted to
* @return The converted value
*
* @exception ConversionException if thrown by an underlying Converter
*/
public T convert(final T value, final Class targetType) {
Class sourceType = value == null ? null : value.getClass();
Object converted = value;
Converter converter = this.lookup(sourceType, targetType);
if (converter != null) {
converted = converter.convert(targetType, value);
}
if (targetType == String.class && converted != null && !(converted instanceof String)) {
// NOTE: For backwards compatibility, if the Converter
// doesn't handle conversion-->String then
// use the registered String Converter
converter = this.lookup(String.class);
if (converter != null) {
converted = converter.convert(String.class, converted);
}
// If the object still isn't a String, use toString() method
if (converted != null && !(converted instanceof String)) {
converted = converted.toString();
}
}
return (T) converted;
}
/**
* Remove all registered {@link Converter}s, and re-establish the
* standard Converters.
*/
public void deregister() {
this.converters.clear();
this.registerPrimitives(false);
this.registerStandard(false, false);
this.registerOther(true);
this.registerArrays(false, 0);
}
/**
* Register the provided converters with the specified defaults.
*
* @param throwException true if the converters should
* throw an exception when a conversion error occurs, otherwise
* false if a default value should be used.
* @param defaultNull trueif the standard converters
* (see {@link ConverterBean#registerStandard(boolean, boolean)})
* should use a default value of null, otherwise false.
* N.B. This values is ignored if throwException is true
* @param defaultArraySize The size of the default array value for array converters
* (N.B. This values is ignored if throwException is true).
* Specifying a value less than zero causes a null value to be used for
* the default.
*/
public void register(final boolean throwException, final boolean defaultNull, final int defaultArraySize) {
this.registerPrimitives(throwException);
this.registerStandard(throwException, defaultNull);
this.registerOther(throwException);
this.registerArrays(throwException, defaultArraySize);
}
/**
* Register the converters for primitive types.
*
* This method registers the following converters:
*
* Boolean.TYPE - {@link BooleanConverter}Byte.TYPE - {@link ByteConverter}Character.TYPE - {@link CharacterConverter}Double.TYPE - {@link DoubleConverter}Float.TYPE - {@link FloatConverter}Integer.TYPE - {@link IntegerConverter}Long.TYPE - {@link LongConverter}Short.TYPE - {@link ShortConverter}
* @param throwException true if the converters should
* throw an exception when a conversion error occurs, otherwise
* false if a default value should be used.
*/
private void registerPrimitives(final boolean throwException) {
this.register(Boolean.TYPE, throwException ? new BooleanConverter() : new BooleanConverter(Boolean.FALSE));
this.register(Byte.TYPE, throwException ? new ByteConverter() : new ByteConverter(ConverterBean.ZERO));
this.register(Character.TYPE, throwException ? new CharacterConverter() : new CharacterConverter(ConverterBean.SPACE));
this.register(Double.TYPE, throwException ? new DoubleConverter() : new DoubleConverter(ConverterBean.ZERO));
this.register(Float.TYPE, throwException ? new FloatConverter() : new FloatConverter(ConverterBean.ZERO));
this.register(Integer.TYPE, throwException ? new IntegerConverter() : new IntegerConverter(ConverterBean.ZERO));
this.register(Long.TYPE, throwException ? new LongConverter() : new LongConverter(ConverterBean.ZERO));
this.register(Short.TYPE, throwException ? new ShortConverter() : new ShortConverter(ConverterBean.ZERO));
}
/**
* Register the converters for standard types.
*
* This method registers the following converters:
*
* BigDecimal.class - {@link BigDecimalConverter}BigInteger.class - {@link BigIntegerConverter}Boolean.class - {@link BooleanConverter}Byte.class - {@link ByteConverter}Character.class - {@link CharacterConverter}Double.class - {@link DoubleConverter}Float.class - {@link FloatConverter}Integer.class - {@link IntegerConverter}Long.class - {@link LongConverter}Short.class - {@link ShortConverter}String.class - {@link StringConverter}
* @param throwException true if the converters should
* throw an exception when a conversion error occurs, otherwise
* false if a default value should be used.
* @param defaultNull trueif the standard converters
* (see {@link ConverterBean#registerStandard(boolean, boolean)})
* should use a default value of null, otherwise false.
* N.B. This values is ignored if throwException is true
*/
private void registerStandard(final boolean throwException, final boolean defaultNull) {
Number defaultNumber = defaultNull ? null : ConverterBean.ZERO;
BigDecimal bigDecDeflt = defaultNull ? null : new BigDecimal("0.0");
BigInteger bigIntDeflt = defaultNull ? null : new BigInteger("0");
Boolean booleanDefault = defaultNull ? null : Boolean.FALSE;
Character charDefault = defaultNull ? null : ConverterBean.SPACE;
String stringDefault = defaultNull ? null : "";
//
this.register(BigDecimal.class, throwException ? new BigDecimalConverter() : new BigDecimalConverter(bigDecDeflt));
this.register(BigInteger.class, throwException ? new BigIntegerConverter() : new BigIntegerConverter(bigIntDeflt));
this.register(Boolean.class, throwException ? new BooleanConverter() : new BooleanConverter(booleanDefault));
this.register(Byte.class, throwException ? new ByteConverter() : new ByteConverter(defaultNumber));
this.register(Character.class, throwException ? new CharacterConverter() : new CharacterConverter(charDefault));
this.register(Double.class, throwException ? new DoubleConverter() : new DoubleConverter(defaultNumber));
this.register(Float.class, throwException ? new FloatConverter() : new FloatConverter(defaultNumber));
this.register(Integer.class, throwException ? new IntegerConverter() : new IntegerConverter(defaultNumber));
this.register(Long.class, throwException ? new LongConverter() : new LongConverter(defaultNumber));
this.register(Short.class, throwException ? new ShortConverter() : new ShortConverter(defaultNumber));
this.register(String.class, throwException ? new StringConverter() : new StringConverter(stringDefault));
}
/**
* Register the converters for other types.
*
* This method registers the following converters:
*
* Class.class - {@link ClassConverter}java.util.Date.class - {@link DateConverter}java.util.Calendar.class - {@link CalendarConverter}File.class - {@link FileConverter}java.sql.Date.class - {@link SqlDateConverter}java.sql.Time.class - {@link SqlTimeConverter}java.sql.Timestamp.class - {@link SqlTimestampConverter}URL.class - {@link URLConverter}
* @param throwException true if the converters should
* throw an exception when a conversion error occurs, otherwise
* false if a default value should be used.
*/
private void registerOther(final boolean throwException) {
this.register(Class.class, throwException ? new ClassConverter() : new ClassConverter(null));
this.register(java.util.Date.class, throwException ? new DateConverter() : new DateConverter(null));
this.register(Calendar.class, throwException ? new CalendarConverter() : new CalendarConverter(null));
this.register(File.class, throwException ? new FileConverter() : new FileConverter(null));
this.register(java.sql.Date.class, throwException ? new SqlDateConverter() : new SqlDateConverter(null));
this.register(java.sql.Time.class, throwException ? new SqlTimeConverter() : new SqlTimeConverter(null));
this.register(Timestamp.class, throwException ? new SqlTimestampConverter() : new SqlTimestampConverter(null));
this.register(URL.class, throwException ? new URLConverter() : new URLConverter(null));
this.register(URI.class, throwException ? new URIConverter() : new URIConverter(null));
this.register(Enum.class, throwException ? new EnumConverter() : new EnumConverter(null));
}
/**
* Register array converters.
*
* @param throwException true if the converters should
* throw an exception when a conversion error occurs, otherwise
* false if a default value should be used.
* @param defaultArraySize The size of the default array value for array converters
* (N.B. This values is ignored if throwException is true).
* Specifying a value less than zero causes a null value to be used for
* the default.
*/
private void registerArrays(final boolean throwException, final int defaultArraySize) {
// Primitives
this.registerArrayConverter(Boolean.TYPE, new BooleanConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Byte.TYPE, new ByteConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Character.TYPE, new CharacterConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Double.TYPE, new DoubleConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Float.TYPE, new FloatConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Integer.TYPE, new IntegerConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Long.TYPE, new LongConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Short.TYPE, new ShortConverter(), throwException, defaultArraySize);
// Standard
this.registerArrayConverter(BigDecimal.class, new BigDecimalConverter(), throwException, defaultArraySize);
this.registerArrayConverter(BigInteger.class, new BigIntegerConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Boolean.class, new BooleanConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Byte.class, new ByteConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Character.class, new CharacterConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Double.class, new DoubleConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Float.class, new FloatConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Integer.class, new IntegerConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Long.class, new LongConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Short.class, new ShortConverter(), throwException, defaultArraySize);
this.registerArrayConverter(String.class, new StringConverter(), throwException, defaultArraySize);
// Other
this.registerArrayConverter(Class.class, new ClassConverter(), throwException, defaultArraySize);
this.registerArrayConverter(java.util.Date.class, new DateConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Calendar.class, new DateConverter(), throwException, defaultArraySize);
this.registerArrayConverter(File.class, new FileConverter(), throwException, defaultArraySize);
this.registerArrayConverter(java.sql.Date.class, new SqlDateConverter(), throwException, defaultArraySize);
this.registerArrayConverter(java.sql.Time.class, new SqlTimeConverter(), throwException, defaultArraySize);
this.registerArrayConverter(Timestamp.class, new SqlTimestampConverter(), throwException, defaultArraySize);
this.registerArrayConverter(URL.class, new URLConverter(), throwException, defaultArraySize);
}
/**
* Register a new ArrayConverter with the specified element delegate converter
* that returns a default array of the specified size in the event of conversion errors.
*
* @param componentType The component type of the array
* @param componentConverter The converter to delegate to for the array elements
* @param throwException Whether a conversion exception should be thrown or a default
* value used in the event of a conversion error
* @param defaultArraySize The size of the default array
*/
private void registerArrayConverter(final Class componentType, final Converter componentConverter, final boolean throwException, final int defaultArraySize) {
Class arrayType = Array.newInstance(componentType, 0).getClass();
Converter arrayConverter = null;
if (throwException) {
arrayConverter = new ArrayConverter(arrayType, componentConverter);
} else {
arrayConverter = new ArrayConverter(arrayType, componentConverter, defaultArraySize);
}
this.register(arrayType, arrayConverter);
}
/** strictly for convenience since it has same parameter order as Map.put */
private void register(final Class clazz, final Converter converter) {
this.register(new ConverterFacade(converter), clazz);
}
/**
* Remove any registered {@link Converter} for the specified destination
* Class.
*
* @param clazz Class for which to remove a registered Converter
*/
public void deregister(final Class clazz) {
this.converters.remove(clazz);
}
/**
* Look up and return any registered {@link Converter} for the specified
* destination class; if there is no registered Converter, return
* null.
*
* @param clazz Class for which to return a registered Converter
* @return The registered {@link Converter} or null if not found
*/
public Converter lookup(final Class clazz) {
Converter conv = (Converter) this.converters.get(clazz);
if (conv != null) {
return conv;
}
for (Object regType : this.converters.keySet()) {
if (((Class) regType).isAssignableFrom(clazz)) {
return (Converter) this.converters.get(regType);
}
}
return null;
}
/**
* Look up and return any registered {@link Converter} for the specified
* source and destination class; if there is no registered Converter,
* return null.
*
* @param sourceType Class of the value being converted
* @param targetType Class of the value to be converted to
* @return The registered {@link Converter} or null if not found
*/
public Converter lookup(final Class sourceType, final Class targetType) {
if (targetType == null) {
throw new IllegalArgumentException("Target type is missing");
}
if (sourceType == null) {
return this.lookup(targetType);
}
Converter converter = null;
// Convert --> String
if (targetType == String.class) {
converter = this.lookup(sourceType);
if (converter == null && (sourceType.isArray() || Collection.class.isAssignableFrom(sourceType))) {
converter = this.lookup(String[].class);
}
if (converter == null) {
converter = this.lookup(String.class);
}
return converter;
}
// Convert --> String array
if (targetType == String[].class) {
if (sourceType.isArray() || Collection.class.isAssignableFrom(sourceType)) {
converter = this.lookup(sourceType);
}
if (converter == null) {
converter = this.lookup(String[].class);
}
return converter;
}
return this.lookup(targetType);
}
/**
* Register a custom {@link Converter} for the specified destination
* Class, replacing any previously registered Converter.
*
* @param converter Converter to be registered
* @param clazz Destination class for conversions performed by this
* Converter
*/
public void register(final Converter converter, final Class clazz) {
this.converters.put(clazz, converter);
}
}