8077 – add "empty" EL operator

Bug 8077 - add "empty" EL operator

Summary: add "empty" EL operator

Status:	RESOLVED FIXED

Alias:	None

Product:	Taglibs
Classification:	Unclassified
Component:	Standard Taglib (show other bugs)
Version:	unspecified
Hardware:	All All

Importance:	P3 normal (vote)
Target Milestone:	---
Assignee:	Tomcat Developers Mailing List

URL:
Keywords:

Depends on:
Blocks:

Reported:	2002-04-14 23:11 UTC by Nathan Abramson
Modified:	2004-11-16 19:05 UTC (History)
CC List:	0 users

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Description Nathan Abramson 2002-04-14 23:11:13 UTC

Add "empty A" operator with same precedence as "not" and unary minus.
empty A evaluates to true if:

  A is null
  A is a zero-length String
  A is a zero-length array
  A is a List and ((List) A).isEmpty()
  A is a Map and ((Map) A).isEmpty()

otherwise empty A evaluates to false

Comment 1 Nathan Abramson 2002-04-14 23:35:20 UTC

The empty EL operator has been added as EmptyOperator.java