/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.graph.types.valuearray;

import org.apache.flink.api.common.typeinfo.TypeInfo;
import org.apache.flink.core.io.IOReadableWritable;
import org.apache.flink.types.CopyableValue;
import org.apache.flink.types.NormalizableKey;
import org.apache.flink.types.ResettableValue;
import org.apache.flink.types.Value;

import java.io.Serializable;

/**
 * Basic interface for array types which reuse objects during serialization.
 *
 * Value arrays are usable as grouping keys but not sorting keys.
 *
 * @param <T> the {@link Value} type
 */
@TypeInfo(ValueArrayTypeInfoFactory.class)
public interface ValueArray<T>
extends Iterable<T>, IOReadableWritable, Serializable, NormalizableKey<ValueArray<T>>, ResettableValue<ValueArray<T>>, CopyableValue<ValueArray<T>> {

	/**
	 * Returns the number of elements stored in the array.
	 *
	 * @return the number of elements stored in the array
	 */
	int size();

	/**
	 * An bounded array fills when the allocated capacity has been fully used.
	 * An unbounded array will only fill when the underlying data structure has
	 * reached capacity, for example the ~2^31 element limit for Java arrays.
	 *
	 * @return whether the array is full
	 */
	boolean isFull();

	/**
	 * Appends the value to this array if and only if the array capacity would
	 * not be exceeded.
	 *
	 * @param value the value to add to this array
	 * @return whether the value was added to the array
	 */
	boolean add(T value);

	/**
	 * Appends all of the values in the specified array to the end of this
	 * array. If the combined array would exceed capacity then no values are
	 * appended.
	 *
	 * @param source array containing values to be added to this array
	 * @return whether the values were added to the array
	 */
	boolean addAll(ValueArray<T> source);

	/**
	 * Saves the array index, which can be restored by calling {@code reset()}.
	 *
	 * This is not serialized and is not part of the contract for
	 * {@link #equals(Object)}.
	 */
	void mark();

	/**
	 * Restores the array index to when {@code mark()} was last called.
	 */
	void reset();

	/**
	 * Resets the array to the empty state. The implementation is *not*
	 * expected to release the underlying data structure. This allows the array
	 * to be reused with minimal impact on the garbage collector.
	 *
	 * This may reset the {@link #mark()} in order to allow arrays be shrunk.
	 */
	void clear();
}