Simple HashMap analyser which can give you an info about:
- underlying hash table size (bucket count)
- used bucket and indexes
- data stored in buckets with hash - for simplicity data from bucket is converted to Array List
- type of buckets (before conversion) - linked nodes or self balanced red black binary search tree
Analyse map usage
HashMap<String, Integer> map = new HashMap<>();
map.put("a", 1);
map.put("b", 2);
map.put("c", 3);
// new analyser intance with key and value types
HashMapAnalyser<String, Integer> analszer = new HashMapAnalszer<>(String.class, Integer.class);
// HashMapMetadata provides analysed data
HashMapMetadata<String, Integer> hashMapMetadata = analyser.analyse(map);HashMapMetadata structure for given example
Collapse to display structure
HashMapMetadata{
totalBucketsCount=16,
usedBucketsCount=3,
bucketsMetadata=
[
BucketMetadata{
bucketIndex=1,
nodeType=LINKED_LIST_NODE,
nodesData=[
NodeData{
key=a,
value=1,
hashCode=97
}]},
BucketMetadata{
bucketIndex=2,
nodeType=LINKED_LIST_NODE,
nodesData=[
NodeData{
key=b,
value=2,
hashCode=98
}]},
BucketMetadata{
bucketIndex=3,
nodeType=LINKED_LIST_NODE,
nodesData=[
NodeData{
key=c,
value=3,
hashCode=99
}]}
]
}
Sort analysed data and check largest bucket
HashMapAnalszer<String, Integer> analyser = new HashMapAnalyser<>(String.class, Integer.class);
HashMapMetadata<String, Integer> mapMetadata = analyser.analyse(mapWithBucketCollision);
BucketSorter.sort(mapMetadata);
System.out.println(mapMetadata.getBucketsMetadata().stream().findFirst());Tested with OpenJDK [ '12', '13', '15' ].
Java-HashMap-Analyser is licensed under the Apache License, Version 2.0