/*
 * Copyright 2002-2019 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.beans.factory.config;

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

/**
 * Immutable placeholder class used for a property value object when it's
 * a reference to another bean in the factory, to be resolved at runtime.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see BeanDefinition#getPropertyValues()
 * @see org.springframework.beans.factory.BeanFactory#getBean(String)
 * @see org.springframework.beans.factory.BeanFactory#getBean(Class)
 */
public class RuntimeBeanReference implements BeanReference {

        private final String beanName;

        @Nullable
        private final Class<?> beanType;

        private final boolean toParent;

        @Nullable
        private Object source;


        /**
         * Create a new RuntimeBeanReference to the given bean name.
         * @param beanName name of the target bean
         */
        public RuntimeBeanReference(String beanName) {
                this(beanName, false);
        }

        /**
         * Create a new RuntimeBeanReference to the given bean name,
         * with the option to mark it as reference to a bean in the parent factory.
         * @param beanName name of the target bean
         * @param toParent whether this is an explicit reference to a bean in the
         * parent factory
         */
        public RuntimeBeanReference(String beanName, boolean toParent) {
                Assert.hasText(beanName, "'beanName' must not be empty");
                this.beanName = beanName;
                this.beanType = null;
                this.toParent = toParent;
        }

        /**
         * Create a new RuntimeBeanReference to a bean of the given type.
         * @param beanType type of the target bean
         * @since 5.2
         */
        public RuntimeBeanReference(Class<?> beanType) {
                this(beanType, false);
        }

        /**
         * Create a new RuntimeBeanReference to a bean of the given type,
         * with the option to mark it as reference to a bean in the parent factory.
         * @param beanType type of the target bean
         * @param toParent whether this is an explicit reference to a bean in the
         * parent factory
         * @since 5.2
         */
        public RuntimeBeanReference(Class<?> beanType, boolean toParent) {
                Assert.notNull(beanType, "'beanType' must not be empty");
                this.beanName = beanType.getName();
                this.beanType = beanType;
                this.toParent = toParent;
        }


        /**
         * Return the requested bean name, or the fully-qualified type name
         * in case of by-type resolution.
         * @see #getBeanType()
         */
        @Override
        public String getBeanName() {
                return this.beanName;
        }

        /**
         * Return the requested bean type if resolution by type is demanded.
         * @since 5.2
         */
        @Nullable
        public Class<?> getBeanType() {
                return this.beanType;
        }

        /**
         * Return whether this is an explicit reference to a bean in the parent factory.
         */
        public boolean isToParent() {
                return this.toParent;
        }

        /**
         * Set the configuration source {@code Object} for this metadata element.
         * <p>The exact type of the object will depend on the configuration mechanism used.
         */
        public void setSource(@Nullable Object source) {
                this.source = source;
        }

        @Override
        @Nullable
        public Object getSource() {
                return this.source;
        }


        @Override
        public boolean equals(@Nullable Object other) {
                if (this == other) {
                        return true;
                }
                if (!(other instanceof RuntimeBeanReference)) {
                        return false;
                }
                RuntimeBeanReference that = (RuntimeBeanReference) other;
                return (this.beanName.equals(that.beanName) && this.beanType == that.beanType &&
                                this.toParent == that.toParent);
        }

        @Override
        public int hashCode() {
                int result = this.beanName.hashCode();
                result = 29 * result + (this.toParent ? 1 : 0);
                return result;
        }

        @Override
        public String toString() {
                return '<' + getBeanName() + '>';
        }

}