DefaultJpaEntityMetadata.java

/*
 * Copyright 2013-2025 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.jpa.repository.query;

import jakarta.persistence.Entity;

import java.util.function.Function;

import org.jspecify.annotations.Nullable;

import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Default implementation for {@link JpaEntityMetadata}.
 *
 * @author Oliver Gierke
 * @author Christoph Strobl
 */
public class DefaultJpaEntityMetadata<T> implements JpaEntityMetadata<T> {

	private final Class<T> domainType;
	private final @Nullable Entity entity;

	/**
	 * Creates a new {@link DefaultJpaEntityMetadata} for the given domain type.
	 *
	 * @param domainType must not be {@literal null}.
	 */
	public DefaultJpaEntityMetadata(Class<T> domainType) {

		Assert.notNull(domainType, "Domain type must not be null");

		this.domainType = domainType;
		this.entity = AnnotatedElementUtils.findMergedAnnotation(domainType, Entity.class);
	}

	@Override
	public Class<T> getJavaType() {
		return domainType;
	}

	@Override
	public String getEntityName() {
		return getEntityNameOr(DefaultJpaEntityMetadata::unqualify);
	}

	private String getEntityNameOr(Function<Class<?>, String> alternative) {
		return (entity != null && StringUtils.hasText(entity.name())) ? entity.name() : alternative.apply(domainType);
	}

	static String unqualify(Class<?> clazz) {
		return unqualify(clazz.getName());
	}

	static String unqualify(String qualifiedName) {
		int loc = qualifiedName.lastIndexOf('.');
		return loc < 0 ? qualifiedName : qualifiedName.substring(loc + 1);
	}

}