org.springframework.data.repository.core.EntityInformation.java Source code

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Here is the source code for org.springframework.data.repository.core.EntityInformation.java

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/*
 * Copyright 2011-2019 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 {@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.
     *
     * @param entity must never be {@literal null}
     * @return
     */
    boolean isNew(T entity);

    /**
     * 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.
     *
     * @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.
     *
     * @return
     */
    Class<ID> getIdType();
}