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package bjc.utils.esodata;
import bjc.utils.funcdata.FunctionalMap;
import bjc.utils.funcdata.IMap;
/**
* Represents a hierarchical map.
*
* What's useful about this is that you can hand sub-directories to people and
* be able to ensure that they can't write outside of it.
*
* @param K The key type of the map.
* @param V The value type of the map.
*/
public class Directory<K, V> {
private IMap<K, TreeDict<K, V>> children;
private IMap<K, V> data;
/**
* Create a new directory.
*/
public Directory() {
children = new FunctionalMap<>();
data = new FunctionalMap<>();
}
/**
* Create a new sub-directory.
*
* Will fail if a sub-directory of that name already exists.
*
* @param key The name of the new sub-directory.
*
* @return The new sub-directory, or null if one by that name already
* exists.
*/
public Directory<K, V> newSubdirectory(K key) {
if(children.containsKey(key)) return null;
Directory<K, V> kid = new Directory<>();
children.put(key, kid);
return kid;
}
/**
* Check if a given sub-directory exists.
*
* @param key The key to look for the sub-directory under.
*
* @return Whether or not a sub-directory of that name exists.
*/
public boolean hasSubdirectory(K key) {
return children.containsKey(key);
}
/**
* Retrieves a given sub-directory.
*
* @param key The key to retrieve the sub-directory for.
*
* @return The sub-directory under that name.
*
* @throws IllegalArgumentException If the given sub-directory doesn't
* exist.
*/
public Directory<K, V> getSubdirectory(K key) {
return children.get(key);
}
/**
* Insert a data-item into the directory.
*
* @param key The key to insert into.
* @param val The value to insert.
*
* @return The old value of key, or null if such a value didn't exist.
*/
public V put(K key, V val) {
return data.put(key, val);
}
/**
* Check if the directory contains a data-item under the given key.
*
* @param key The key to check for.
*
* @return Whether or not there is a data item for the given key.
*/
public boolean containsKey(K key) {
return data.containsKey(key);
}
/**
* Retrive a given data-item from the directory.
*
* @param key The key to retrieve data for.
*
* @return The value for the given key.
*
* @throws IllegalArgumentException If no value exists for the given
* key.
*/
public V get(K key) {
return data.get(key);
}
}
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