public V put(K key, V value) {
Entry<K,V> t = root;
if (t == null) {
compare(key, key); // type (and possibly null) check
root = new Entry<>(key, value, null);
size = 1;
modCount++;
return null;
}
int cmp;
Entry<K,V> parent;
// split comparator and comparable paths
Comparator<? super K> cpr = comparator;
if (cpr != null) { //If the comparator is not empty, then the size of the key is compared by the comparator
do {
parent = t;
cmp = cpr.compare(key, t.key);
if (cmp < 0) // The comparison result is less than 0, and placed in the left child node
t = t.left;
else if (cmp > 0) // The comparison result is greater than 0 and placed in the right child node
t = t.right;
else
return t.setValue(value); // The result is equal to zero, which means that the key values are equal, overriding the value value
} while (t != null);
}
else { // When no Comparator is passed, use the compareTo method of the key object
if (key == null)
throw new NullPointerException();
@SuppressWarnings("unchecked")
Comparable<? super K> k = (Comparable<? super K>) key;
do {
parent = t;
cmp = k.compareTo(t.key);
if (cmp < 0)
t = t.left;
else if (cmp > 0)
t = t.right;
else
return t.setValue(value);
} while (t != null);
}
Entry<K,V> e = new Entry<>(key, value, parent);
if (cmp < 0)
parent.left = e;
else
parent.right = e;
fixAfterInsertion(e);
size++;
modCount++;
return null;
}
