com.googlecode.objectify.impl.translate.opt.BigDecimalLongTranslatorFactory Maven / Gradle / Ivy
Show all versions of objectify Show documentation
package com.googlecode.objectify.impl.translate.opt;
import com.google.cloud.datastore.LongValue;
import com.google.cloud.datastore.Value;
import com.google.cloud.datastore.ValueType;
import com.googlecode.objectify.impl.translate.SimpleTranslatorFactory;
import java.math.BigDecimal;
/**
* This a simple strategy for storing BigDecimal in the datastore. BigDecimalLongConverter multiplies
* by a fixed factor and stores the result as a Long. This is appropriate for monetary and other (relatively)
* small values with fixed decimal precision.
*
* This is one possible strategy and not appropriate for all uses of BigDecimal - especially very large
* values which cannot fit in a Long. For this reason, the converter is not installed by default. You can
* Install this converter at the same time you perform registration:
*
* ObjectifyService.factory().getTranslators().add(new BigDecimalLongTranslatorFactory());
*
* The default factor of 1,000 is good for currency, which usually has 0-3 digits of precision past
* the decimal point. But you can pick any other factor appropriate to your application.
*
* All custom translators must be registered *before* entity classes are registered.
*
* @author Jeff Schnitzer
*/
public class BigDecimalLongTranslatorFactory extends SimpleTranslatorFactory
{
/** Default factor is 1000, which gives you three digits of precision past the decimal point */
public static final long DEFAULT_FACTOR = 1000;
/** */
private BigDecimal factor;
/**
* Construct this converter with the default factor (1000), which can store three points of
* precision past the decimal point.
*/
public BigDecimalLongTranslatorFactory()
{
this(DEFAULT_FACTOR);
}
/**
* Construct this with an arbitrary factor. Powers of ten are highly recommended if you want to
* be able to interpret the numbers in the datastore viewer.
*
* @param factor number multiplied by before storage and divided by on retrieval.
*/
public BigDecimalLongTranslatorFactory(long factor) {
super(BigDecimal.class, ValueType.LONG);
this.factor = new BigDecimal(factor);
}
@Override
protected BigDecimal toPojo(final Value value) {
return new BigDecimal(value.get()).divide(factor);
}
@Override
protected Value toDatastore(final BigDecimal value) {
return LongValue.of(value.multiply(factor).longValueExact());
}
}