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A library for Java that provides re-usable components commonly used by Flow libraries.
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/*
 * This file is part of Flow Commons, licensed under the MIT License (MIT).
 *
 * Copyright (c) 2013 Flow Powered 
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.flowpowered.commons.store;

import java.util.Collection;
import java.util.Map.Entry;
import java.util.Set;

/**
 * Basic Store interface.
 *
 * It is used to store maps that map Strings to classes of type T
 *
 * Subclasses can implement backing to the file system.
 *
 * Implementing classes must be synchronized
 *
 * This is a two-way map, so each value only maps back to one key
 */
public interface SimpleStore {
    /**
     * Save the map to the persistence system associated with the store.
     *
     * If the store is a memory based volatile map, then this method will have no effect and will always return true.
     *
     * @return returns true if the save was successful
     */
    public boolean save();

    /**
     * Loads the map from the persistence system associated with the store.
     *
     * If the store is a memory based volatile map, then this method will have no effect and will always return true.
     *
     * @return returns true if the load was successful
     */
    public boolean load();

    /**
     * Returns a collection of all keys for all key, value pairs within the Store
     *
     * @return returns a Collection containing all the keys
     */
    public Collection getKeys();

    /**
     * Returns an entry set containing all the key, value pairs within the Store
     *
     * @return returns a Set containing all the keys, value entries
     */
    public Set> getEntrySet();

    /**
     * Returns the number of key, value pairs within the Store
     *
     * @return the size of the store
     */
    public int getSize();

    /**
     * Wipes all the key value pairs for the store
     */
    public boolean clear();

    /**
     * Gets the value associated with a key
     *
     * @return returns the value associated with the key
     */
    public T get(String key);

    /**
     * Gets the value associated with a key and allows a default to be set
     *
     * @return returns the value associated with the key, or the default if there is no mapping
     */
    public T get(String key, T def);

    /**
     * Gets the key associated with a value
     *
     * @return returns the key associated with the value
     */
    public String reverseGet(T value);

    /**
     * Removes a key, value pair
     *
     * @return returns the old value associated with the key, or null if the key, value pair doesn't exist
     */
    public T remove(String key);

    /**
     * Sets the value associated with a key
     *
     * @return returns the old value associated with the key
     */
    public T set(String key, T value);

    /**
     * Sets the value associated with a key, but only if neither the key or value are in use
     *
     * @return true if the key/value pair was set
     */
    public boolean setIfAbsent(String key, T value);
}