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new a1c9a4f add groupByMany blog post (minor tweaks)
a1c9a4f is described below
commit a1c9a4fbad8739ef972048f3466dcebaf71ceb18
Author: Paul King <[email protected]>
AuthorDate: Mon Dec 1 20:11:32 2025 +1000
add groupByMany blog post (minor tweaks)
---
site/src/site/blog/fruity-eclipse-grouping.adoc | 58 ++++++++++++-------------
1 file changed, 29 insertions(+), 29 deletions(-)
diff --git a/site/src/site/blog/fruity-eclipse-grouping.adoc
b/site/src/site/blog/fruity-eclipse-grouping.adoc
index a29e922..76236e2 100644
--- a/site/src/site/blog/fruity-eclipse-grouping.adoc
+++ b/site/src/site/blog/fruity-eclipse-grouping.adoc
@@ -1,5 +1,5 @@
= Grouping Fruity Collections
-Paul King
+Paul King <paulk-asert|PMC_Member>
:revdate: 2025-12-01T10:45:00+00:00
:keywords: eclipse collections, groovy, emoji, many-to-many, grouping
:description: This post looks at using grouping in the context of many-to-many
relationships.
@@ -22,11 +22,11 @@ and is one of the examples carried over into the
aforementioned Groovy blog post
[source,groovy]
----
assert Fruit.ALL.groupBy(Fruit::getColor) ==
- Multimaps.mutable.list.empty()
- .withKeyMultiValues(RED, Fruit.of('🍎'), Fruit.of('🍒'))
- .withKeyMultiValues(ORANGE, Fruit.of('🍑'), Fruit.of('🍊'))
- .withKeyMultiValues(YELLOW, Fruit.of('🍌'))
- .withKeyMultiValues(MAGENTA, Fruit.of('🍇'))
+ Multimaps.mutable.list.empty()
+ .withKeyMultiValues(RED, Fruit.of('🍎'), Fruit.of('🍒'))
+ .withKeyMultiValues(ORANGE, Fruit.of('🍑'), Fruit.of('🍊'))
+ .withKeyMultiValues(YELLOW, Fruit.of('🍌'))
+ .withKeyMultiValues(MAGENTA, Fruit.of('🍇'))
----
We have a collection of fruit and we have colors.
@@ -69,12 +69,12 @@ Here is how we can explore the relationship between fruit
and colors with these
[source,groovy]
----
assert Fruit.ALL.groupByEach(Fruit::getColors) ==
- Multimaps.mutable.list.empty()
- .withKeyMultiValues(GREEN, Fruit.of('🍎'), Fruit.of('🍌'),
Fruit.of('🍇'))
- .withKeyMultiValues(RED, Fruit.of('🍎'), Fruit.of('🍒'))
- .withKeyMultiValues(ORANGE, Fruit.of('🍑'), Fruit.of('🍊'))
- .withKeyMultiValues(YELLOW, Fruit.of('🍌'))
- .withKeyMultiValues(MAGENTA, Fruit.of('🍇'))
+ Multimaps.mutable.list.empty()
+ .withKeyMultiValues(GREEN, Fruit.of('🍎'), Fruit.of('🍌'), Fruit.of('🍇'))
+ .withKeyMultiValues(RED, Fruit.of('🍎'), Fruit.of('🍒'))
+ .withKeyMultiValues(ORANGE, Fruit.of('🍑'), Fruit.of('🍊'))
+ .withKeyMultiValues(YELLOW, Fruit.of('🍌'))
+ .withKeyMultiValues(MAGENTA, Fruit.of('🍇'))
----
Grape colors are sometimes known by the juice or wine they produce (red and
white)
@@ -93,11 +93,11 @@ Collections but just using normal JDK lists and maps:
[source,groovy]
----
var expected = [
- (GREEN) : [Fruit.of('🍎'), Fruit.of('🍌'), Fruit.of('🍇')],
- (RED) : [Fruit.of('🍎'), Fruit.of('🍒')],
- (ORANGE) : [Fruit.of('🍑'), Fruit.of('🍊')],
- (YELLOW) : [Fruit.of('🍌')],
- (MAGENTA) : [Fruit.of('🍇')]
+ (GREEN) : [Fruit.of('🍎'), Fruit.of('🍌'), Fruit.of('🍇')],
+ (RED) : [Fruit.of('🍎'), Fruit.of('🍒')],
+ (ORANGE) : [Fruit.of('🍑'), Fruit.of('🍊')],
+ (YELLOW) : [Fruit.of('🍌')],
+ (MAGENTA) : [Fruit.of('🍇')]
]
----
@@ -111,9 +111,9 @@ in combination with `collectMany` (_flatMap_) and
`collectEntries` (or we could
[source,groovy]
----
assert expected == Fruit.values()
- .collectMany(f -> f.colors.collect{ c -> [c, f] })
- .groupBy{ c, f -> c }
- .collectEntries{ k, v -> [k, v*.get(1)] }
+ .collectMany(f -> f.colors.collect{ c -> [c, f] })
+ .groupBy{ c, f -> c }
+ .collectEntries{ k, v -> [k, v*.get(1)] }
----
This works well but isn't necessarily obvious at first glance.
@@ -166,11 +166,11 @@ representation for our fruit rather than the enum used in
previous examples:
[source,groovy]
----
assert Fruit.values().groupByMany(Fruit::getEmoji, Fruit::getColors) == [
- (GREEN) : ['🍎', '🍌', '🍇'],
- (RED) : ['🍎', '🍒'],
- (ORANGE) : ['🍑', '🍊'],
- (YELLOW) : ['🍌'],
- (MAGENTA) : ['🍇']
+ (GREEN) : ['🍎', '🍌', '🍇'],
+ (RED) : ['🍎', '🍒'],
+ (ORANGE) : ['🍑', '🍊'],
+ (YELLOW) : ['🍌'],
+ (MAGENTA) : ['🍇']
]
----
@@ -183,10 +183,10 @@ As another example, let's group the fruit by the vowels
they contain:
----
var vowels = 'AEIOU'.toSet()
var vowelsOf = { String word -> word.toSet().intersect(vowels) }
-assert Fruit.values().groupByMany(Fruit::getEmoji, fruit ->
vowelsOf(fruit.name())) == [
- A: ['🍎', '🍑', '🍌', '🍊', '🍇'],
- E: ['🍎', '🍑', '🍒', '🍊', '🍇'],
- O: ['🍊']
+assert Fruit.values().groupByMany(Fruit::getEmoji, f -> vowelsOf(f.name())) ==
[
+ A: ['🍎', '🍑', '🍌', '🍊', '🍇'],
+ E: ['🍎', '🍑', '🍒', '🍊', '🍇'],
+ O: ['🍊']
]
----
