java - Container of objects indexed by definite field -


i have set of objects need index definite field of objects. there sample implementation hashmap (update: actually, hashmap used illustration, not insist container looking surely hashmap)

public class foo {     public string id; // field index      // other fields number     public int i;     public double d;     public string description;     public string rule;     public double otherd;      public foo(string id, int i, double d, string description, string rule, double otherd) {         this.id = id;         this.i = i;         this.d = d;         this.description = description;         this.rule = rule;         this.otherd = otherd;     } }

i need have container of foo objects indexed unique string field id. following foohashmap current solution:

hashmap<string, foo> foohashmap = null;  foohashmap.put("bar", foo("bar", 1, 0.3, "aa", "bb", 0.8)); foohashmap.put("tzar", foo("tzar", 8, 12.3, "dlj", "no rule", 0.343)); // etc.

it looks pretty ugly solution doubling id in foo constructor , in hashmap key. can java 8 suggest more elegant solution? not mean solution like

public void addfoo(foo foo) { foohashmap.put(foo.id, foo); }

personally use solution have posted @ end:

addfoo(new foo("bar", 1, 0.3, "aa", "bb", 0.8)); addfoo(new foo("tzar", 8, 12.3, "dlj", "no rule", 0.343));

and let addfoo method handle rest:

public void addfoo(foo foo) {     foohashmap.put(foo.id, foo); }

since apparently have create foo objects anyway can't think of more elegant solution.

if had list of foo objects, create map this

map<string, foo> foomap = foos     .stream()     .collect(collectors.tomap(f -> f.id, f -> f));

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