/** Remove all entries. */
public void clear() {
beforeWrite();
try {
root.removeAllRecursive();
newRoot(Page.createEmpty(this, store.getCurrentVersion()));
} finally {
afterWrite();
}
}
/**
* Remove a key-value pair, if the key exists.
*
* @param key the key (may not be null)
* @return the old value if the key existed, or null otherwise
*/
public V remove(Object key) {
beforeWrite();
try {
long writeVersion = store.getCurrentVersion();
Page p = copyOnWrite(root, writeVersion);
@SuppressWarnings("unchecked")
V result = (V) remove(p, writeVersion, key);
newRoot(p);
return result;
} finally {
afterWrite();
}
}
/**
* Add or replace a key-value pair.
*
* @param key the key (may not be null)
* @param value the value (may not be null)
* @return the old value if the key existed, or null otherwise
*/
@SuppressWarnings("unchecked")
public V put(K key, V value) {
DataUtils.checkArgument(value != null, "The value may not be null");
beforeWrite();
try {
long writeVersion = store.getCurrentVersion();
Page p = copyOnWrite(root, writeVersion);
p = splitRootIfNeeded(p, writeVersion);
Object result = put(p, writeVersion, key, value);
newRoot(p);
return (V) result;
} finally {
afterWrite();
}
}