/*
* Copyright 2000-2013 JetBrains s.r.o.
*
* 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 com.intellij.openapi.actionSystem;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.Nullable;
/**
* Allows a component hosting actions to provide context information to the actions. When a specific
* data item is requested, the component hierarchy is walked up from the currently focused component,
* and every component implementing the <code>DataProvider</code> interface is queried for the data
* until one of them returns the data. Data items can also be mapped to each other - for example,
* if a data provider provides an item for {@link CommonDataKeys#NAVIGATABLE}, an item for
* {@link CommonDataKeys#NAVIGATABLE_ARRAY} can be generated from it automatically.
*
* @see DataContext
*/
public interface DataProvider {
/**
* Returns the object corresponding to the specified data identifier. Some of the supported
* data identifiers are defined in the {@link com.intellij.openapi.actionSystem.PlatformDataKeys} class.
*
* @param dataId the data identifier for which the value is requested.
* @return the value, or null if no value is available in the current context for this identifier.
*/
@Nullable
Object getData(@NonNls String dataId);
}