[PDFBOX-1512] TextPositionComparator is not compatible with Java 7

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.1, 2.0.0
• Fix Version/s: 1.8.8, 2.0.0
• Component/s: Text extraction
• Environment: Java 7
• Assignee: Andreas Lehmkühler
• Reporter: Benjamin Papez
• Created: 07/Feb/13 09:36
• Updated: 27/Nov/15 23:12
• Resolved: 12/Oct/14 13:11

Description

The TextPostionCompartor causes the following exception running on Java 7: Unexpected RuntimeException from org.apache.tika.parser.ParserDecorator$1@9007fa2 Original cause: Comparison method violates its general contract!

I think the problem is with this check:

if ( yDifference < .1 ||
(pos2YBottom >= pos1YTop && pos2YBottom <= pos1YBottom) ||
(pos1YBottom >= pos2YTop && pos1YBottom <= pos2YBottom))

as it violates the contract requirement:

The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

Finally, the implementor must ensure that compare(x, y)==0 implies that sgn(compare(x, z))==sgn(compare(y, z)) for all z.

Java 7 now is strict and throws exceptions when the contract is violated.

Issue Links

• blocks: TIKA-972 Unexpected RuntimeException from org.apache.tika.parser.pdf.PDFParser .
• is related to: PDFBOX-731 Inconsistencies in TextPositionComparator and sortByPosition
• is related to: PDFBOX-2996 StackOverflow in Quicksort