com.cognifide.slice.api.context.Context Maven / Gradle / Ivy
/*-
* #%L
* Slice - Core API
* %%
* Copyright (C) 2012 Cognifide Limited
* %%
* 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.
* #L%
*/
package com.cognifide.slice.api.context;
import aQute.bnd.annotation.ConsumerType;
import com.cognifide.slice.api.scope.ContextScoped;
import com.google.inject.Key;
/**
* @author Rafał Malinowski
*
* Stores objects which are scoped with {@link ContextScoped}. Objects are identified by {@link Key}. Null
* values can be stored. Use contains() to check if given Key is available in Context. Calling get() and
* checking for null is not enough, because Context can store null values as well.
*/
@ConsumerType
public interface Context {
/**
* Check if value for given key is stored in this Context.
*
* @param key key to check
* @param class of the key
* @return true if value for key is stored
*/
boolean contains(Key key);
/**
* Put new object for given key. Object can be null.
*
* @param key key to store new object under
* @param object new object to store or null
* @param class of the key
*/
void put(Key key, T object);
/**
* Get value stored under given key. If no value or null value was stored this method will return null.
* Use contains() to differentiate between these two cases.
*
* @param key key to get value for
* @param class of the key
* @return value for given key
*/
T get(Key key);
}