ExecutionContext.java

/**
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.aries.blueprint.di;

import java.util.concurrent.Future;

import org.osgi.service.blueprint.container.ReifiedType;

public interface ExecutionContext {

    public static final class Holder {

        private static final ThreadLocal<ExecutionContext> context = new ThreadLocal<ExecutionContext>();

        private Holder() {
        }

        public static ExecutionContext getContext() {
            ExecutionContext executionContext = context.get();
            if (executionContext == null) {
                throw new IllegalStateException("Execution container has not been set");
            }
            return executionContext;
        }

        public static ExecutionContext setContext(ExecutionContext newContext) {
            ExecutionContext oldContext = context.get();
            context.set(newContext);
            return oldContext;
        }

    }

    /**
     * Adds a recipe to the top of the execution stack.  If the recipe is already on
     * the stack, a CircularDependencyException is thrown.
     * @param recipe the recipe to add to the stack
     * @throws CircularDependencyException if the recipe is already on the stack
     */
    public void push(Recipe recipe) throws CircularDependencyException;

    /**
     * Removes the top recipe from the execution stack.
     * @return the top recipe on the stack
     */
    public Recipe pop();

    /**
     * Does this context contain a object with the specified name.
     *
     * @param name the unique name of the object instance
     * @return true if this context contain a object with the specified name
     */
    public boolean containsObject(String name);

    /**
     * Gets the object or recipe with the specified name from the repository.
     *
     * @param name the unique name of the object instance
     * @return the object instance, a recipe to build the object or null
     */
    public Object getObject(String name);

    /**
     * Try to add a full object and return the already registered future if available
     * @param name
     * @param object
     * @return
     */
    public Future<Object> addFullObject(String name, Future<Object> object);
    
    public void addPartialObject(String name, Object object);
    
    public Object getPartialObject(String name);
    
    public void removePartialObject(String name);

    public Object convert(Object value, ReifiedType type) throws Exception;
    
    public boolean canConvert(Object value, ReifiedType type);

    public Class loadClass(String className) throws ClassNotFoundException;

    public Recipe getRecipe(String name);
    
}