Using empty filters (= or <>) on an annotation column with units results in NullPointerException

[Nicklas Nordborg]

1. Create an annotation type for any kind of item. Select any unit and quantity.
2. Go to the list page and display the column for the new annotation type.
3. Try to filter with '=' or '<>' on the annotation column.

NullPointerException:null is displayed on the page and no results are returned. The log contains the stack trace:

19:29:42,404  WARN Application:1077 - Could not filter on 'Sample.#6'
java.lang.NullPointerException
        at java.util.regex.Matcher.getTextLength(Matcher.java:1140)
        at java.util.regex.Matcher.reset(Matcher.java:291)
        at java.util.regex.Matcher.<init>(Matcher.java:211)
        at java.util.regex.Pattern.matcher(Pattern.java:888)
        at net.sf.basedb.util.units.UnitUtil.splitValueWithUnit(UnitUtil.java:87)
        at net.sf.basedb.core.PropertyFilter.getValueAsObject(PropertyFilter.java:262)
        at net.sf.basedb.core.PropertyFilter.getRestriction(PropertyFilter.java:492)
        at net.sf.basedb.core.ItemContext.configureQuery(ItemContext.java:1058)
        at net.sf.basedb.clients.web.Base.getConfiguredQuery(Base.java:939)
        at org.apache.jsp.biomaterials.samples.list_005fsamples_jsp._jspService(list_005fsamples_jsp.java:252)

Filtering on specific values seems to work.

[Nicklas Nordborg]

(In [4692]) Fixes #1207: Using empty filters (= or <>) on an annotation column with units results in NullPointerException