TaskContext.java

/*
 * Copyright 2012-2015, the original author or authors.
 *
 * 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.flipkart.phantom.task.spi;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.flipkart.phantom.task.spi.TaskRequestWrapper;
import com.flipkart.phantom.task.spi.TaskResult;

import java.util.Map;
import java.util.concurrent.Future;

/**
 * <code>TaskContext</code> provides methods for {@link com.flipkart.phantom.task.impl.TaskHandler} to communicate with it's Component Container - to execute tasks on other TaskHandler instances,
 * perform profiling operations and result serialization.
 *
 * @author devashishshankar
 * @author regunath.balasubramanian
 *
 * @version 1.0, 19th March, 2013
 * @version 2.0, 11th July, 2013
 */
@SuppressWarnings("rawtypes")
public interface TaskContext {

    /**
     * Gets the config from the ConfigTaskHandler.
     * @param group group name of the object to be fetched
     * @param key the primary key
     * @return the config as string, empty string if not found/error
     */
    public String getConfig(String group, String key, int count);

    /**
     * Executes a task identified by the specified command name. This command executes synchronously
     * @param commandName the command to execute
     * @param data the command processing data
     * @param params data parameters
     * @return a TaskResult instance with the execution outcome
     * @throws UnsupportedOperationException in case none of the registered TaskHandler instances support the specified command
     */
	public <S> TaskResult executeCommand(String commandName, S data, Map<String,Object> params) throws UnsupportedOperationException;

    /**
     * Executes a task identified by the specified command name. This command executes synchronously.
     * This execute Command is to be called by clients who wish to have control over the response decode process.
     * The TaskResult thus formed will contain the instance of data T as decoded by the Decoder.
     * @param commandName the command to execute
     * @param taskRequestWrapper params for processing the request
     * @param decoder Decoder to be Implemented by clients to process the response
     * @return a TaskResult instance with the execution outcome
     * @throws UnsupportedOperationException in case none of the registered TaskHandler instances support the specified command
     */
    public <T, S> TaskResult<T> executeCommand(String commandName, TaskRequestWrapper<S> taskRequestWrapper, Decoder<T> decoder) throws UnsupportedOperationException;

    /**
     * Executes a task identified by the specified command name. This command executes synchronously.
     * This execute Command is to be called by clients who wish to have control over the response decode process.
     * The TaskResult thus formed will contain the instance of data T as decoded by the Decoder.
     * @param commandName the command to execute
     * @param data the command processing data
     * @param params data parameters
     * @param decoder Decoder to be Implemented by clients to process the response
     * @return a TaskResult instance with the execution outcome
     * @throws UnsupportedOperationException in case none of the registered TaskHandler instances support the specified command
     */
    public <T, S> TaskResult<T> executeCommand(String commandName, S data, Map<String, Object> params, Decoder<T> decoder) throws UnsupportedOperationException;

    /**
     * Executes a task asynchronously identified by the specified command name.
     * This execute Command is to be called by clients who wish to have control over the response decode process.
     * The TaskResult thus formed will contain the instance of data T as decoded by the Decoder.
     * @param commandName the command to execute
     * @param data the command processing data
     * @param params data parameters
     * @param decoder Decoder to be Implemented by clients to process the response
     * @return a TaskResult instance with the execution outcome
     * @throws UnsupportedOperationException in case none of the registered TaskHandler instances support the specified command
     */
    public <S> Future<TaskResult> executeAsyncCommand(String commandName, S data, Map<String, Object> params, Decoder decoder) throws UnsupportedOperationException;

    /**
     * Executes a command asynchronously and returns a {@link Future} to get the {@link TaskResult} from
     * @see TaskContext#executeCommand(String, java.lang.Object, java.util.Map)
     */
    public <S> Future<TaskResult> executeAsyncCommand(String commandName, S data, Map<String, Object> params) throws UnsupportedOperationException;

    /** Gets the ObjectMapper instance for result serialization to JSON*/
    public ObjectMapper getObjectMapper();

    /** Gets Host Name of current server */
    public String getHostName();
}