Binary search trees - Data Structures and Problem Solving Using Java - page 750

51 // Pair class
52 protected static abstract class Pair<KeyType,ValueType>
53 implements Map.Entry<KeyType,ValueType>
54 {
55 public Pair( KeyType k, ValueType v )
56 { key = k; value = v; }
57
58 final public KeyType getKey( )
59 { return key; }
60
61 final public ValueType getValue( )
62 { return value; }
63
64 final public ValueType setValue( ValueType newValue )

{ ValueType oldValue = value; value = newValue; return oldValue; }

65

66
67 final public String toString( )
68 { return key + "=" + value; }
69
70 private KeyType key;
71 private ValueType value;
72 }
73
74 // Views
75 public Set<KeyType> keySet( )
76 { return new KeySetClass( ); }
77 public Collection<ValueType> values( )
78 { return new ValueCollectionClass( ); }
79 public Set<Map.Entry<KeyType,ValueType>> entrySet( )
80 { return getSet( ); }
81
82 private abstract class ViewClass<AnyType> extends AbstractCollection<AnyType>
83 { /* Figure 19.80 */ }
84 private class KeySetClass extends ViewClass<KeyType> implements Set<KeyType>
85 { /* Figure 19.80 */ }
86 private class ValueCollectionClass extends ViewClass<ValueType>
87 { /* Figure 19.80 */ }
88
89 private class ValueCollectionIterator implements Iterator<ValueType>
90 { /* Figure 19.81 */ }
91 private class KeySetIterator implements Iterator<KeyType>
92 { /* Figure 19.81 */ }
93 }

figure 19.78
Abstract MapImpl helper class skeleton (part 2)