org.testifyproject.trait.PropertiesReader Maven / Gradle / Ivy

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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.List;
import java.util.Map;
import java.util.Optional;
import static java.util.Optional.ofNullable;

/**
 * 
 * A contracts that specifies methods for reading property values. 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 PropertiesReader extends PropertiesTrait {

    /**
     * Find a map typed associated with the given mapKey and return an instance
     * of PropertiesReader that wraps the found map.
     *
     * @param mapKey the key key associated with the map
     * @return an instance that wraps the found map
     */
    default PropertiesReader getPropertiesReader(String mapKey) {
        Map result = findMap(mapKey);

        return DefaultPropertiesReader.of(result);
    }

    /**
     * Get the value the value associated with the given key.
     *
     * @param  the value type
     * @param key the key
     * @return the value to which the specified key is mapped, null otherwise
     */
    default  T getProperty(String key) {
        return (T) getProperties().get(key);
    }

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

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

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

        return result;
    }

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

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

        return result;
    }

}