de.escalon.hypermedia.action.Options Maven / Gradle / Ivy
/*
* Copyright (c) 2014. Escalon System-Entwicklung, Dietrich Schulten
*
* 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 de.escalon.hypermedia.action;
/**
* Allows to determine possible values for an argument annotated with {@link Select}.
*
* @author Dietrich Schulten
*/
public interface Options {
/**
* Gets possible values for an argument annotated with {@link Select}. The default implementation {@link
* StringOptions} just passes on a given String array as possible values. Sometimes the possible values are more
* dynamic and depend on the context. Therefore, an Options implementation can also determine possible values based
* on another argument to the same call. The example below shows how to get possible options from a custom
* DetailOptions implementation which needs a personId for that:
*
* @RequestMapping("/customer/{personId}/details")
* public HttpEntity<Resource<List<String>> showDetails(
* @PathVariable Long personId,
* @RequestParam("detail")
* @Select(options = DetailOptions.class, args = "personId")
* List<String> details) {
* ...
* }
*
* The @Select annotation above says that the possible detail values come from a DetailOptions
* class which determines those values based on the personId. Note how the personId is passed to
* showDetails as argument to the same call, alongside the details argument. This allows us to resolve
* the "personId" arg defined for DetailOptions to an actual value.
Within the call to {@link
* Options#get} the args array contains the values specified by the args annotation attribute in the given order
* . In
* the example above, DetailOptions receives the personId and can read possible options for that particular
* person.
*
* @param value
* parameters to be used by the implementation. Could be literal values as used by {@link StringOptions} or
* some argument to a custom implementation of Options, such as an SQL string.
* @param args
* from the same method call, as defined by {@link Select#args()}. The possible values for a parameter
* might
* depend on the context. In that case, you can use {@link Select#args()} to pass other argument values
* received in the same method call to an implementation of {@link Options}. See above for an example.
* @return possible values
* @see StringOptions
*/
public Object[] get(String[] value, Object... args);
}