This example shows how to include/exclude generic type conversions based on metadata provided by source/target TypeDescriptor.
package com.logicbig.example;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.ConditionalGenericConverter;
import org.springframework.core.convert.support.DefaultConversionService;
import java.math.BigDecimal;
import java.util.Collections;
import java.util.Set;
public class ConditionalGenericConverterExample {
public static void main (String[] args) {
DefaultConversionService service = new DefaultConversionService();
service.addConverter(new NumberToBigDecimalConverter());
BigDecimal bd = service.convert(Double.valueOf("2222.336"),
BigDecimal.class);
bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP);
System.out.println(bd);
//this will return the same BigDecimal instance without conversion
bd = service.convert(new BigDecimal("898.33"), BigDecimal.class);
System.out.println(bd);
}
public static class NumberToBigDecimalConverter implements
ConditionalGenericConverter {
@Override
public boolean matches (TypeDescriptor sourceType,
TypeDescriptor targetType) {
return sourceType.getType() != BigDecimal.class;
}
@Override
public Set<ConvertiblePair> getConvertibleTypes () {
return Collections.singleton(new ConvertiblePair(Number.class,
BigDecimal.class));
}
@Override
public Object convert (Object source, TypeDescriptor sourceType,
TypeDescriptor targetType) {
Number number = (Number) source;
return new BigDecimal(number.doubleValue());
}
}
}
Output
2222.34
898.33
This example shows how to include/exclude generic type conversions based on metadata provided by source/target TypeDescriptor.
package com.logicbig.example;
import org.springframework.core.convert.support.DefaultConversionService;
import java.math.BigDecimal;
public class ConditionalGenericConverterExample {
public static void main(String[] args) {
DefaultConversionService service = new DefaultConversionService();
service.addConverter(new NumberToBigDecimalConverter());
BigDecimal bd = service.convert(Double.valueOf("2222.336"),
BigDecimal.class);
bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP);
System.out.println("result: " + bd);
System.out.println("----------");
//this will return the same BigDecimal instance without conversion
BigDecimal bd2 = new BigDecimal("898.33");
bd = service.convert(bd2, BigDecimal.class);
System.out.println("result: " + bd);
System.out.println(bd == bd2);
}
}
Output
converting :2222.336
result: 2222.34
----------
result: 898.33
true
package com.logicbig.example;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.ConditionalGenericConverter;
import java.math.BigDecimal;
import java.util.Collections;
import java.util.Set;
public class NumberToBigDecimalConverter implements ConditionalGenericConverter {
@Override
public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
return sourceType.getType() != BigDecimal.class;
}
@Override
public Set<ConvertiblePair> getConvertibleTypes() {
return Collections.singleton(new ConvertiblePair(Number.class,
BigDecimal.class));
}
@Override
public Object convert(Object source, TypeDescriptor sourceType,
TypeDescriptor targetType) {
System.out.println("converting :"+source);
Number number = (Number) source;
return new BigDecimal(number.doubleValue());
}
}
