org.neo4j.driver.types.MapAccessor Maven / Gradle / Ivy

/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * 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.neo4j.driver.types;

import java.util.Map;
import java.util.function.Function;
import org.neo4j.driver.Value;
import org.neo4j.driver.Values;
import org.neo4j.driver.exceptions.ClientException;
import org.neo4j.driver.internal.value.NullValue;

/**
 * Access the keys, properties and values of an underlying unordered map by key
 *
 * This provides only read methods. Subclasses may chose to provide additional methods
 * for changing the underlying map.
 * @since 1.0
 */
public interface MapAccessor {
    /**
     * Retrieve the keys of the underlying map
     *
     * @return all map keys in unspecified order
     */
    Iterable keys();

    /**
     * Check if the list of keys contains the given key
     *
     * @param key the key
     * @return {@code true} if this map keys contains the given key otherwise {@code false}
     */
    boolean containsKey(String key);

    /**
     * Retrieve the value of the property with the given key
     *
     * @param key the key of the property
     * @return the property's value or a {@link NullValue} if no such key exists
     * @throws ClientException if record has not been initialized
     */
    Value get(String key);

    /**
     * Retrieve the number of entries in this map
     *
     * @return the number of entries in this map
     */
    int size();

    /**
     * Retrieve all values of the underlying collection
     *
     * @return all values in unspecified order
     */
    Iterable values();

    /**
     * Map and retrieve all values of the underlying collection
     *
     * @param mapFunction a function to map from Value to T. See {@link Values} for some predefined functions, such
     * as {@link Values#ofBoolean()}, {@link Values#ofList(Function)}.
     * @param  the target type of mapping
     * @return the result of mapping all values in unspecified order
     */
     Iterable values(Function mapFunction);

    /**
     * Return the underlying map as a map of string keys and values converted using
     * {@link Value#asObject()}.
     *
     * This is equivalent to calling {@link #asMap(Function)} with {@link Values#ofObject()}.
     *
     * @return the value as a Java map
     */
    Map asMap();

    /**
     * @param mapFunction a function to map from Value to T. See {@link Values} for some predefined functions, such
     * as {@link Values#ofBoolean()}, {@link Values#ofList(Function)}.
     * @param  the type of map values
     * @see Values for a long list of built-in conversion functions
     * @return the value as a map from string keys to values of type T obtained from mapping he original map values, if possible
     */
     Map asMap(Function mapFunction);
}