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/*
 * Copyright 2016-2017 Testify Project.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.testifyproject.trait;

import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import static java.util.Optional.ofNullable;

/**
 * 
 * A contracts that specifies Properties trait. Classes that implement this
 * interface have the ability to associate and manage properties with the
 * implementation class.
 * 
 * 
 * Note that with respect to null keys and values the behavior the methods in
 * contract are dependent on the {@link Map} implementation returned by {@link #getProperties()
 * }
 * 
 *
 * @author saden
 */
public interface PropertiesTrait {

    /**
     * Get the properties associated with this implementation of
     * PropertiesTrait.
     *
     * @param  map entry value type
     * @return a map containing key/value pairs
     */
     Map getProperties();

    /**
     * Find the value associated with the given key.
     *
     * @param  the value type
     * @param key the key
     * @return an optional with the value, empty optional otherwise
     */
    default  Optional findProperty(String key) {
        return ofNullable((T) getProperties().get(key));
    }

    /**
     * Add the given key/value pair if it is absent.
     *
     * @param  the value type
     * @param key the key
     * @param value the value
     */
    default  void addProperty(String key, T value) {
        Map properties = getProperties();

        properties.computeIfAbsent(key, p -> value);
    }

    /**
     * Find a list value associated with the given key. If the list is not found
     * an {@link Collections#EMPTY_LIST} will be returned.
     *
     * @param  the collection element type
     * @param key the key
     * @return an optional with the value, empty optional otherwise
     */
    default  List findList(String key) {
        Map> properties = getProperties();
        List result = properties.get(key);

        if (result == null) {
            result = Collections.EMPTY_LIST;
        }

        return result;
    }

    /**
     * Add the given element to a collection entry in the properties map with
     * the given key.
     *
     * @param  the element type
     * @param key the properties map key
     * @param element the element that will be added
     */
    default  void addListElement(String key, E element) {
        Map> properties = getProperties();

        List result = properties.computeIfAbsent(key, p -> new LinkedList<>());
        result.add(element);
    }

    /**
     * Find a map typed associated with the given key. If the map is not found
     * an {@link Collections#EMPTY_MAP} is returned.
     *
     * @param  the map key type
     * @param  the map value type
     * @param key the key
     * @return the found map, empty map otherwise
     */
    default  Map findMap(String key) {
        Map> properties = getProperties();
        Map result = properties.get(key);

        if (result == null) {
            result = Collections.EMPTY_MAP;
        }

        return result;
    }

    /**
     * Add the given entryKey/entryValue pair to a map entry in the properties
     * map with the given key.
     *
     * @param  the entry key type
     * @param  the entry value type
     * @param key the properties map key
     * @param entryKey the new entry key that will be added
     * @param entryValue the new entry value that will be added
     */
    default  void addMapEntry(String key, K entryKey, V entryValue) {
        Map> properties = getProperties();

        Map result = properties.computeIfAbsent(key, p -> new HashMap<>());
        result.computeIfAbsent(entryKey, k -> entryValue);
    }

}