[GROOVY-3788] HashMap support for easy filtering on keys or values

• Type: New Feature
• Status: Closed
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: 1.7-beta-1
• Component/s: groovy-jdk
• Assignee: Jochen Theodorou
• Reporter: kristianm
• Created: 24/Sep/09 05:58
• Updated: 08/Jun/12 08:47
• Resolved: 08/Jun/12 08:47

Description

Proposed Enhancements to HashMap:

• rejectKeys(list of keys)
• rejectValues(list of values)
• includeKeys(list of keys)
• includeValues(list of values)

Some examples:

HashMap.metaClass.rejectKeys = {ArrayList keys ->
    delegate.findAll{ k,v -> !keys.contains(k)}
} 

HashMap.metaClass.rejectValues = {ArrayList values ->
    delegate.findAll{ k,v -> !values.contains(v)}
} 

HashMap.metaClass.includeKeys = {ArrayList keys ->
    delegate.findAll{ k,v -> keys.contains(k)}
}

HashMap.metaClass.includeValues = {ArrayList values ->
    delegate.findAll{ k,v -> values.contains(v)}
} 


map = [a:1, b:2, c:3, d:4]

keys = ['a', 'c']

values = [1, 2]

def not_rejected = map.rejectKeys(keys)
def included = map.includeKeys(keys)

def not_rejected_v = map.rejectValues(values)
def included_v = map.includeValues(values)

println not_rejected
println included

println not_rejected_v
println included_v

with output:

[b:2, d:4]
[a:1, c:3]
[c:3, d:4]
[a:1, b:2]