/**
* Node in the Tree. Doubles as a means to pass key-value pairs back to
* user (see ).
*/
static final class Entry<K,V> implements Map.Entry<K,V> {
K key; //键
V value; //值
Entry<K,V> left = null; //指向其左节点
Entry<K,V> right = null; //指向其右节点
Entry<K,V> parent; //指向其父节点
boolean color = BLACK; //添加的节点是黑色的
/**
* Make a new cell with given key, value, and parent, and with
* {@code null} child links, and BLACK color.
*/
Entry(K key, V value, Entry<K,V> parent) {
this.key = key;
this.value = value;
this.parent = parent;
}
/**
* Returns the key.
*
* @return the key
*/
public K getKey() {
return key;
}
/**
* Returns the value associated with the key.
*
* @return the value associated with the key
*/
public V getValue() {
return value;
}
/**
* Replaces the value currently associated with the key with the given
* value.
*
* @return the value associated with the key before this method was
* called
*/
public V setValue(V value) {
V oldValue = this.value;
this.value = value;
return oldValue;
}
public boolean equals(Object o) {
if (!(o instanceof ))
return false;
<?,?> e = (<?,?>)o;
return valEquals(key,()) && valEquals(value,());
}
public int hashCode() {
int keyHash = (key==null ? 0 : ());
int valueHash = (value==null ? 0 : ());
return keyHash ^ valueHash;
}
public String toString() {
return key + "=" + value;
}
}