/**
+ * @author Ed Spencer
+ * @class Ext.data.Batch
+ *
+ * <p>Provides a mechanism to run one or more {@link Ext.data.Operation operations} in a given order. Fires the 'operationcomplete' event
+ * after the completion of each Operation, and the 'complete' event when all Operations have been successfully executed. Fires an 'exception'
+ * event if any of the Operations encounter an exception.</p>
+ *
+ * <p>Usually these are only used internally by {@link Ext.data.proxy.Proxy} classes</p>
+ *
+ * @constructor
+ * @param {Object} config Optional config object
+ */
+Ext.define('Ext.data.Batch', {
+ mixins: {
+ observable: 'Ext.util.Observable'
+ },
+
+ /**
+ * True to immediately start processing the batch as soon as it is constructed (defaults to false)
+ * @property autoStart
+ * @type Boolean
+ */
+ autoStart: false,
+
+ /**
+ * The index of the current operation being executed
+ * @property current
+ * @type Number
+ */
+ current: -1,
+
+ /**
+ * The total number of operations in this batch. Read only
+ * @property total
+ * @type Number
+ */
+ total: 0,
+
+ /**
+ * True if the batch is currently running
+ * @property isRunning
+ * @type Boolean
+ */
+ isRunning: false,
+
+ /**
+ * True if this batch has been executed completely
+ * @property isComplete
+ * @type Boolean
+ */
+ isComplete: false,
+
+ /**
+ * True if this batch has encountered an exception. This is cleared at the start of each operation
+ * @property hasException
+ * @type Boolean
+ */
+ hasException: false,
+
+ /**
+ * True to automatically pause the execution of the batch if any operation encounters an exception (defaults to true)
+ * @property pauseOnException
+ * @type Boolean
+ */
+ pauseOnException: true,
+
+ constructor: function(config) {
+ var me = this;
+
+ me.addEvents(
+ /**
+ * @event complete
+ * Fired when all operations of this batch have been completed
+ * @param {Ext.data.Batch} batch The batch object
+ * @param {Object} operation The last operation that was executed
+ */
+ 'complete',
+
+ /**
+ * @event exception
+ * Fired when a operation encountered an exception
+ * @param {Ext.data.Batch} batch The batch object
+ * @param {Object} operation The operation that encountered the exception
+ */
+ 'exception',
+
+ /**
+ * @event operationcomplete
+ * Fired when each operation of the batch completes
+ * @param {Ext.data.Batch} batch The batch object
+ * @param {Object} operation The operation that just completed
+ */
+ 'operationcomplete'
+ );
+
+ me.mixins.observable.constructor.call(me, config);
+
+ /**
+ * Ordered array of operations that will be executed by this batch
+ * @property operations
+ * @type Array
+ */
+ me.operations = [];
+ },
+
+ /**
+ * Adds a new operation to this batch
+ * @param {Object} operation The {@link Ext.data.Operation Operation} object
+ */
+ add: function(operation) {
+ this.total++;
+
+ operation.setBatch(this);
+
+ this.operations.push(operation);
+ },
+
+ /**
+ * Kicks off the execution of the batch, continuing from the next operation if the previous
+ * operation encountered an exception, or if execution was paused
+ */
+ start: function() {
+ this.hasException = false;
+ this.isRunning = true;
+
+ this.runNextOperation();
+ },
+
+ /**
+ * @private
+ * Runs the next operation, relative to this.current.
+ */
+ runNextOperation: function() {
+ this.runOperation(this.current + 1);
+ },
+
+ /**
+ * Pauses execution of the batch, but does not cancel the current operation
+ */
+ pause: function() {
+ this.isRunning = false;
+ },
+
+ /**
+ * Executes a operation by its numeric index
+ * @param {Number} index The operation index to run
+ */
+ runOperation: function(index) {
+ var me = this,
+ operations = me.operations,
+ operation = operations[index],
+ onProxyReturn;
+
+ if (operation === undefined) {
+ me.isRunning = false;
+ me.isComplete = true;
+ me.fireEvent('complete', me, operations[operations.length - 1]);
+ } else {
+ me.current = index;
+
+ onProxyReturn = function(operation) {
+ var hasException = operation.hasException();
+
+ if (hasException) {
+ me.hasException = true;
+ me.fireEvent('exception', me, operation);
+ } else {
+ me.fireEvent('operationcomplete', me, operation);
+ }
+
+ if (hasException && me.pauseOnException) {
+ me.pause();
+ } else {
+ operation.setCompleted();
+ me.runNextOperation();
+ }
+ };
+
+ operation.setStarted();
+
+ me.proxy[operation.action](operation, onProxyReturn, me);
+ }
+ }
+});