/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.internal.vm.compiler.collections;

/**

 * Unmodifiable memory efficient map data structure.

 *

 * @since 19.0

 */

public interface UnmodifiableEconomicMap<K, V> {

    /**

     * Returns the value to which {@code key} is mapped, or {@code null} if this map contains no

     * mapping for {@code key}.

     *

     * @since 19.0

     */

    V get(K key);

    /**

     * Returns the value to which {@code key} is mapped, or {@code defaultValue} if this map

     * contains no mapping for {@code key}.

     *

     * @since 19.0

     */

    default V get(K key, V defaultValue) {

        V v = get(key);

        if (v == null) {

            return defaultValue;

        }

        return v;

    }

    /**

     * Returns {@code true} if this map contains a mapping for {@code key}.

     *

     * @since 19.0

     */

    boolean containsKey(K key);

    /**

     * Returns the number of key-value mappings in this map.

     *

     * @since 19.0

     */

    int size();

    /**

     * Returns {@code true} if this map contains no key-value mappings.

     *

     * @since 19.0

     */

    boolean isEmpty();

    /**

     * Returns a {@link Iterable} view of the values contained in this map.

     *

     * @since 19.0

     */

    Iterable<V> getValues();

    /**

     * Returns a {@link Iterable} view of the keys contained in this map.

     *

     * @since 19.0

     */

    Iterable<K> getKeys();

    /**

     * Returns a {@link UnmodifiableMapCursor} view of the mappings contained in this map.

     *

     * @since 19.0

     */

    UnmodifiableMapCursor<K, V> getEntries();

}