001/*
002 * Copyright 2012-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.boot.context.properties;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025import org.springframework.core.annotation.AliasFor;
026
027/**
028 * Annotation for externalized configuration. Add this to a class definition or a
029 * {@code @Bean} method in a {@code @Configuration} class if you want to bind and validate
030 * some external Properties (e.g. from a .properties file).
031 * <p>
032 * Note that contrary to {@code @Value}, SpEL expressions are not evaluated since property
033 * values are externalized.
034 *
035 * @author Dave Syer
036 * @see ConfigurationPropertiesBindingPostProcessor
037 * @see EnableConfigurationProperties
038 */
039@Target({ ElementType.TYPE, ElementType.METHOD })
040@Retention(RetentionPolicy.RUNTIME)
041@Documented
042public @interface ConfigurationProperties {
043
044        /**
045         * The name prefix of the properties that are valid to bind to this object. Synonym
046         * for {@link #prefix()}. A valid prefix is defined by one or more words separated
047         * with dots (e.g. {@code "acme.system.feature"}).
048         * @return the name prefix of the properties to bind
049         */
050        @AliasFor("prefix")
051        String value() default "";
052
053        /**
054         * The name prefix of the properties that are valid to bind to this object. Synonym
055         * for {@link #value()}. A valid prefix is defined by one or more words separated with
056         * dots (e.g. {@code "acme.system.feature"}).
057         * @return the name prefix of the properties to bind
058         */
059        @AliasFor("value")
060        String prefix() default "";
061
062        /**
063         * Flag to indicate that when binding to this object invalid fields should be ignored.
064         * Invalid means invalid according to the binder that is used, and usually this means
065         * fields of the wrong type (or that cannot be coerced into the correct type).
066         * @return the flag value (default false)
067         */
068        boolean ignoreInvalidFields() default false;
069
070        /**
071         * Flag to indicate that when binding to this object unknown fields should be ignored.
072         * An unknown field could be a sign of a mistake in the Properties.
073         * @return the flag value (default true)
074         */
075        boolean ignoreUnknownFields() default true;
076
077}