D Green created LANG-985:
----------------------------
Summary: ToStringBuilder reliably handle OpenPojo @BusinessKey
annotated instances
Key: LANG-985
URL: https://issues.apache.org/jira/browse/LANG-985
Project: Commons Lang
Issue Type: Wish
Components: lang.builder.*
Reporter: D Green
Priority: Minor
We use Google's OpenPojo library, annotating DTOs and persistence entities with
@BusinessKey in order to remove boilerplate hashcode() and equals().
I recently started noticing toString() was throwing exceptions when I didn't
populate @BusinessKey annotated field(s) as I was using the Null Object
Pattern. A workaround was to populate dummy values but there's a risk this
could be considered a real value further down the line, so looked for an
alternative solution and came up with the following extending
StandardToStringStyle:-
import org.apache.commons.lang3.builder.StandardToStringStyle;
import org.apache.commons.lang3.builder.ToStringStyle;
import com.openpojo.business.annotation.BusinessKey;
import com.openpojo.business.exception.BusinessException;
public class CustomToStringStyle extends StandardToStringStyle {
public static final ToStringStyle OPENPOJO_SAFE_STYLE =
createOpenPojoSafeStyle();
/**
* Works better with {@link BusinessKey} annotated OpenPojo classes.
*
* This instance does not call {@link ToStringStyle}.register(...)
* which can throw a {@link BusinessException} if the key hasn't been
* populated, for example if you used the Null Object Pattern.
*/
private static ToStringStyle createOpenPojoSafeStyle() {
final StandardToStringStyle style = new StandardToStringStyle();
style.setUseClassName(false);
style.setUseIdentityHashCode(false);
return style;
}
}
Used as follows:
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this,
CustomToStringStyle.OPENPOJO_SAFE_STYLE);
}
I realise this doesn't handle recursion in fields because it skips over
ToStringStyle.register(..) but this suffices for our use case right now -
perhaps an alternative implementation overriding register() that uses a List
(with documented performance penalty) could be added.
Is there anything already in Commons that could do this? If not we would like
this to be considered for inclusion in commons lang (happy to help out with
development), potentially with implementation improvements by those who know
the code base better.
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