如何过滤哈希图并查找第一次出现

Question

i have converted my hashmap to json as i dont know what itt looks like in java

so my hashmap looks like

{"1":[true,false],
"2":[true,true],
"3":[true]}

i need to get the first occurance of all true in the array list in a single key

in this case its 2 is the 1st occurance

so if there is an occurance ///do something else //do somethig else

   hm.forEach((key, value) -> {

            for (Object object : value) {

                   boolean b = (boolean)object;
                   if(!b){
                   break;
                    }else{
                       System.out.println(key+"->"+b);
                   }

            }
});

i tried something like this but im getting lost in the mix here its testing alotall the cases

any help would be greatly appreciated

Answer 1

You can use this schema

hm.entrySet().stream().filter(SomeClass::isAllBoolean)
        .findFirst()
        .ifPresent(System.out::println);

private static boolean isAllBoolean(Map.Entry<String, List<Boolean>> values) {

}

SomeClass is a class where isAllBoolean method is located.

Answer 2

try the snippet below.

hm.forEach((key, value) -> {
            boolean allTrue=true;
                        for (Object object : value) {
                            allTrue = (boolean)object;
                            if(!allTrue){ //stop if you found a false in the true/false array
                                break;
                            }
                        }//out of the inner iteration
                        if(allTrue){//if this variable is true, it means the above iteration had all values true
                            //do your stuff
                            break;
                        }
                        allTrue=true; //reset
            });

Answer 3

Clearly you need a filter to check for an all-true boolean array, a findFirst to find the first one and a get to handle the fact that findFirst returns an Optional .

public void test(String[] args) {
    Map<String, Boolean[]> hm = new HashMap<>();
    hm.put("1", new Boolean[]{true, false});
    hm.put("2", new Boolean[]{true, true});
    hm.put("3", new Boolean[]{true});
    Map.Entry<String, Boolean[]> first = hm.entrySet().stream()
            .filter(es -> allTrue(es.getValue()))
            .findFirst()
            .orElse(null);
    System.out.println(first.getKey()+" -> "+ Arrays.toString(first.getValue()));
}

private boolean allTrue(Boolean[] a) {
    for (Boolean b : a) {
        if (!b) return false;
    }
    return true;
}

prints

2 -> [true, true]

BTW: The order of iteration of a Map is not defined so you are relying on undocumented features by trying to capture the first one.