http://stackoverflow.com/questions/20144826#40363641, Java

http://stackoverflow.com/questions/20144826#40363641

Language: Layout:

//'main' method must be in a class 'Rextester'.
//Compiler version 1.8.0_72

import java.util.*;
import java.lang.*;
import java.util.stream.Collectors;

class Rextester
{  
    public static void main(String args[])
    {
        int[][][] int3dArray = { { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } },
                { { 10, 11, 12 }, { 13, 14, 15 }, { 16, 17, 18 } },
                { { 19, 20, 21 }, { 22, 23, 24 }, { 25, 26, 27 }, { 28 }, { 29, 30 } } };
        String[][] string2dArray = { { "He, llo" }, { "Wo", "rld" } };
        String[] stringArray = { "Hello", "World" };
        Set<Integer> integersSet = new HashSet<Integer>();
        integersSet.add(1);
        integersSet.add(2);
        integersSet.add(3);

Map<String, String> stringMap = new HashMap<>();
        stringMap.put("key1", "value1");
        stringMap.put("key2", "value2");
        stringMap.put("key3", "value3");

Queue<String> qe = new LinkedList<String>();
        qe.add("x");
        qe.add("y");
        qe.add("z");

Object[] objectArray = { "Hell", 0, "W", 0, "orld", integersSet, stringMap, qe };

List<Object> mixList = new ArrayList<Object>();
        mixList.add("String");
        mixList.add(3);
        mixList.add(string2dArray);

System.out.println(flatten(mixList));

mixList.add(int3dArray);

System.out.println(flatten(mixList, true));
    }
    
    public static List<Object> flatten(Collection<Object> collection) {
        return flatten(collection, false);
    }    
    
    public static List<Object> flatten(Collection<Object> collection, boolean unique) {
        List<Object> result;
        if (unique) {
            result = collection.stream()
                .flatMap(Collection::stream)
                .flatMap(m -> m.values().stream())
                .flatMap(Collection::stream)
                .distinct()
                .collect(Collectors.toList());        
        } else {
            result = collection.stream()
                .flatMap(Collection::stream)
                .flatMap(m -> m.values().stream())
                .flatMap(Collection::stream)
                .collect(Collectors.toList());        
        }
        
        return result;
    }    
}

[ + ] Show input
Compilation time: 0.62 sec, absolute service time: 0,74 sec

edit mode | history

Error(s), warning(s):

source_file.java:54: error: incompatible types: cannot infer type-variable(s) R
                .flatMap(Collection::stream)
                        ^
    (argument mismatch; invalid method reference
      method stream in interface Collection<E> cannot be applied to given types
        required: no arguments
        found: Object
        reason: actual and formal argument lists differ in length)
  where R,T,E are type-variables:
    R extends Object declared in method <R>flatMap(Function<? super T,? extends Stream<? extends R>>)
    T extends Object declared in interface Stream
    E extends Object declared in interface Collection
source_file.java:54: error: invalid method reference
                .flatMap(Collection::stream)
                         ^
  non-static method stream() cannot be referenced from a static context
  where E is a type-variable:
    E extends Object declared in interface Collection
source_file.java:56: error: invalid method reference
                .flatMap(Collection::stream)
                         ^
  non-static method stream() cannot be referenced from a static context
  where E is a type-variable:
    E extends Object declared in interface Collection
source_file.java:61: error: incompatible types: cannot infer type-variable(s) R
                .flatMap(Collection::stream)
                        ^
    (argument mismatch; invalid method reference
      method stream in interface Collection<E> cannot be applied to given types
        required: no arguments
        found: Object
        reason: actual and formal argument lists differ in length)
  where R,T,E are type-variables:
    R extends Object declared in method <R>flatMap(Function<? super T,? extends Stream<? extends R>>)
    T extends Object declared in interface Stream
    E extends Object declared in interface Collection
source_file.java:61: error: invalid method reference
                .flatMap(Collection::stream)
                         ^
  non-static method stream() cannot be referenced from a static context
  where E is a type-variable:
    E extends Object declared in interface Collection
source_file.java:63: error: invalid method reference
                .flatMap(Collection::stream)
                         ^
  non-static method stream() cannot be referenced from a static context
  where E is a type-variable:
    E extends Object declared in interface Collection
6 errors

λ

                                      .NET NoSQL database for rapid development