/*
 * Copyright 2011-2020 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.data.repository.core;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

Extension of EntityMetadata to add functionality to query information of entity instances. 
Author:
Oliver Gierke, Mark Paluch
See Also:
PersistentEntityInformation/**
 * Extension of {@link EntityMetadata} to add functionality to query information of entity instances.
 *
 * @author Oliver Gierke
 * @author Mark Paluch
 * @see org.springframework.data.repository.core.support.PersistentEntityInformation
 */
public interface EntityInformation<T, ID> extends EntityMetadata<T> {

	
Returns whether the given entity is considered to be new.
Params:
entity – must never be null
Returns:
/**
	 * Returns whether the given entity is considered to be new.
	 *
	 * @param entity must never be {@literal null}
	 * @return
	 */
	boolean isNew(T entity);

	
Returns the id of the given entity or null if none can be obtained. 
Params:
entity – must never be null
Returns:
/**
	 * Returns the id of the given entity or {@literal null} if none can be obtained.
	 *
	 * @param entity must never be {@literal null}
	 * @return
	 */
	@Nullable
	ID getId(T entity);

	
Returns the identifier of the given entity.
Params:
entity – must not be null.
Throws:
IllegalArgumentException – in case no id could be obtained from the given entity
Returns:
the identifier of the given entity
Since:
2.0/**
	 * Returns the identifier of the given entity.
	 *
	 * @param entity must not be {@literal null}.
	 * @return the identifier of the given entity
	 * @throws IllegalArgumentException in case no id could be obtained from the given entity
	 * @since 2.0
	 */
	default ID getRequiredId(T entity) throws IllegalArgumentException {

		Assert.notNull(entity, "Entity must not be null!");

		ID id = getId(entity);

		if (id != null) {
			return id;
		}

		throw new IllegalArgumentException(String.format("Could not obtain required identifier from entity %s!", entity));
	}

	
Returns the type of the id of the entity.
Returns:
/**
	 * Returns the type of the id of the entity.
	 *
	 * @return
	 */
	Class<ID> getIdType();
}