117 lines
4.6 KiB
JavaScript
117 lines
4.6 KiB
JavaScript
// Copyright 2010 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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* @fileoverview An interface for asynchronous message-passing channels.
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*
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* This interface is useful for writing code in a message-passing style that's
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* independent of the underlying communication medium. It's also useful for
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* adding decorators that wrap message channels and add extra functionality on
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* top. For example, {@link goog.messaging.BufferedChannel} enqueues messages
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* until communication is established, while {@link goog.messaging.MultiChannel}
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* splits a single underlying channel into multiple virtual ones.
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*
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* Decorators should be passed their underlying channel(s) in the constructor,
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* and should assume that those channels are already connected. Decorators are
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* responsible for disposing of the channels they wrap when the decorators
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* themselves are disposed. Decorators should also follow the APIs of the
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* individual methods listed below.
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*
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*/
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goog.provide('goog.messaging.MessageChannel');
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/**
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* @interface
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*/
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goog.messaging.MessageChannel = function() {};
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/**
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* Initiates the channel connection. When this method is called, all the
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* information needed to connect the channel has to be available.
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*
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* Implementers should only require this method to be called if the channel
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* needs to be configured in some way between when it's created and when it
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* becomes active. Otherwise, the channel should be immediately active and this
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* method should do nothing but immediately call opt_connectCb.
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*
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* @param {Function=} opt_connectCb Called when the channel has been connected
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* and is ready to use.
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*/
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goog.messaging.MessageChannel.prototype.connect = function(opt_connectCb) {};
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/**
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* Gets whether the channel is connected.
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*
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* If {@link #connect} is not required for this class, this should always return
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* true. Otherwise, this should return true by the time the callback passed to
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* {@link #connect} has been called and always after that.
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*
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* @return {boolean} Whether the channel is connected.
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*/
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goog.messaging.MessageChannel.prototype.isConnected = function() {};
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/**
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* Registers a service to be called when a message is received.
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*
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* Implementers shouldn't impose any restrictions on the service names that may
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* be registered. If some services are needed as control codes,
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* {@link goog.messaging.MultiMessageChannel} can be used to safely split the
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* channel into "public" and "control" virtual channels.
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*
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* @param {string} serviceName The name of the service.
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* @param {function((string|!Object))} callback The callback to process the
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* incoming messages. Passed the payload. If opt_objectPayload is set, the
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* payload is decoded and passed as an object.
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* @param {boolean=} opt_objectPayload If true, incoming messages for this
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* service are expected to contain an object, and will be deserialized from
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* a string automatically if necessary. It's the responsibility of
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* implementors of this class to perform the deserialization.
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*/
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goog.messaging.MessageChannel.prototype.registerService =
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function(serviceName, callback, opt_objectPayload) {};
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/**
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* Registers a service to be called when a message is received that doesn't
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* match any other services.
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*
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* @param {function(string, (string|!Object))} callback The callback to process
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* the incoming messages. Passed the service name and the payload. Since
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* some channels can pass objects natively, the payload may be either an
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* object or a string.
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*/
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goog.messaging.MessageChannel.prototype.registerDefaultService =
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function(callback) {};
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/**
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* Sends a message over the channel.
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*
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* @param {string} serviceName The name of the service this message should be
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* delivered to.
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* @param {string|!Object} payload The value of the message. If this is an
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* Object, it is serialized to a string before sending if necessary. It's
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* the responsibility of implementors of this class to perform the
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* serialization.
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*/
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goog.messaging.MessageChannel.prototype.send =
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function(serviceName, payload) {};
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