MetadataParam.java

/**
 * Copyright 2010-2016 Ralph Schaer <ralphschaer@gmail.com>
 *
 * 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
 *
 *   http://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 ch.ralscha.extdirectspring.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.web.bind.annotation.ValueConstants;

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MetadataParam {

	/**
	 * The name of the metadata parameter to bind to.
	 */
	String value() default "";

	/**
	 * Whether the parameter is required.
	 * <p>
	 * Default is {@code true}, leading to an exception thrown in case of the parameter
	 * missing in the request. Switch this to {@code false} if you prefer a {@code null}
	 * in case of the parameter missing.
	 * <p>
	 * Alternatively, provide a {@link #defaultValue() defaultValue}, which implicitly
	 * sets this flag to {@code false}.
	 */
	boolean required() default true;

	/**
	 * The default value to use as a fallback when the request parameter value is not
	 * provided or empty. Supplying a default value implicitly sets {@link #required()} to
	 * false.
	 */
	String defaultValue() default ValueConstants.DEFAULT_NONE;

}