java key/value cache v2

package reghzy.api.utils;

/**
 * A helper class for caching map entries. This is only really intended to be used if the map isn't modified often
 * @param <K> The key
 * @param <V> The value
 */
public abstract class KVObjectCache<K, V> {
    private K lastAccessedKey;
    private V lastAccessedValue;

    /**
     * Gets the cached value if it isn't null, and the key is equal to this cache's cached key. Otherwise, it calls {@link KVObjectCache#getValue(Object)}
     * @param key
     * @return
     */
    public V get(K key) {
        K thisKey = this.lastAccessedKey;
        V value;
        if (key == thisKey) {
            if ((value = this.lastAccessedValue) == null) {
                return this.lastAccessedValue = getValue(key);
            }

            return value;
        }
        else if (key == null) {
            this.lastAccessedKey = null;
            return this.lastAccessedValue = getValue(null);
        }
        else if (key.equals(thisKey)) {
            this.lastAccessedKey = key;
            if ((value = this.lastAccessedValue) == null) {
                return this.lastAccessedValue = getValue(key);
            }

            return value;
        }
        else {
            this.lastAccessedKey = key;
            return this.lastAccessedValue = getValue(key);
        }
    }

    /**
     * An abstract method for getting the value from a key
     * @param key The key
     * @return The value
     */
    public abstract V getValue(K key);

    /**
     * Clears the cached key and value
     */
    public void clear() {
        this.lastAccessedKey = null;
        this.lastAccessedValue = null;
    }

    /**
     * Invalidates the currently held cached object, if the given key matches this cache's key
     */
    public void invalidate(K key) {
        K thisKey = this.lastAccessedKey;
        if (key == thisKey) {
            this.lastAccessedKey = null;
        }
        else if (key != null && key.equals(thisKey)) {
            this.lastAccessedKey = null;
        }
    }
}