| 8 | |
| 9 | public class CollectionMethods { |
| 10 | public static void main(String[] args) { |
| 11 | Collection<String> c = |
| 12 | new ArrayList<>(LIST.subList(0, 4)); |
| 13 | c.add("ten"); |
| 14 | c.add("eleven"); |
| 15 | show(c); |
| 16 | border(); |
| 17 | // Make an array from the List: |
| 18 | Object[] array = c.toArray(); |
| 19 | // Make a String array from the List: |
| 20 | String[] str = c.toArray(new String[0]); |
| 21 | // Find max and min elements; this means |
| 22 | // different things depending on the way |
| 23 | // the Comparable interface is implemented: |
| 24 | System.out.println( |
| 25 | "Collections.max(c) = " + Collections.max(c)); |
| 26 | System.out.println( |
| 27 | "Collections.min(c) = " + Collections.min(c)); |
| 28 | border(); |
| 29 | // Add a Collection to another Collection |
| 30 | Collection<String> c2 = |
| 31 | new ArrayList<>(LIST.subList(10, 14)); |
| 32 | c.addAll(c2); |
| 33 | show(c); |
| 34 | border(); |
| 35 | c.remove(LIST.get(0)); |
| 36 | show(c); |
| 37 | border(); |
| 38 | // Remove all components that are |
| 39 | // in the argument collection: |
| 40 | c.removeAll(c2); |
| 41 | show(c); |
| 42 | border(); |
| 43 | c.addAll(c2); |
| 44 | show(c); |
| 45 | border(); |
| 46 | // Is an element in this Collection? |
| 47 | String val = LIST.get(3); |
| 48 | System.out.println( |
| 49 | "c.contains(" + val + ") = " + c.contains(val)); |
| 50 | // Is a Collection in this Collection? |
| 51 | System.out.println( |
| 52 | "c.containsAll(c2) = " + c.containsAll(c2)); |
| 53 | Collection<String> c3 = |
| 54 | ((List<String>)c).subList(3, 5); |
| 55 | // Keep all the elements that are in both |
| 56 | // c2 and c3 (an intersection of sets): |
| 57 | c2.retainAll(c3); |
| 58 | show(c2); |
| 59 | // Discard all c2 elements that also appear in c3: |
| 60 | c2.removeAll(c3); |
| 61 | System.out.println( |
| 62 | "c2.isEmpty() = " + c2.isEmpty()); |
| 63 | border(); |
| 64 | // Functional operation: |
| 65 | c = new ArrayList<>(LIST); |
| 66 | c.removeIf(s -> !s.startsWith("P")); |
| 67 | c.removeIf(s -> s.startsWith("Pale")); |