chore(Viewer+Modeler): inherit from Diagram

* simplifies event handling
* relies on Diagram#clear to reset the diagram before
  successive imports
* allows diagram services to be re-used across imports
* allows diagram services to be injected (or retrieved)
  before import

Closes #237

lib/Modeler.js

@@ -109,8 +109,8 @@ Modeler.prototype.createDiagram = function(done) {
   return this.importXML(initialDiagram, done);
 };
 
-Modeler.prototype.createModdle = function() {
+Modeler.prototype._createModdle = function(options) {
-  var moddle = Viewer.prototype.createModdle.call(this);
+  var moddle = Viewer.prototype._createModdle.call(this, options);
 
   moddle.ids = new Ids([ 32, 36, 1 ]);
 

lib/Viewer.js

@@ -18,17 +18,12 @@ var domify = require('min-dom/lib/domify'),
 var Diagram = require('diagram-js'),
     BpmnModdle = require('bpmn-moddle');
 
+
+var inherits = require('inherits');
+
 var Importer = require('./import/Importer');
 
 
-function initListeners(diagram, listeners) {
-  var events = diagram.get('eventBus');
-
-  listeners.forEach(function(l) {
-    events.on(l.event, l.priority, l.callback, l.that);
-  });
-}
-
 function checkValidationError(err) {
 
   // check if we can help the user by indicating wrong BPMN 2.0 xml
@@ -110,39 +105,23 @@ function ensureUnit(val) {
  */
 function Viewer(options) {
 
-  this.options = options = assign({}, DEFAULT_OPTIONS, options || {});
+  options = assign({}, DEFAULT_OPTIONS, options);
 
-  this.moddle = this.createModdle();
+  this.moddle = this._createModdle(options);
 
-  var parent = options.container;
+  this.container = this._createContainer(options);
-
-  // support jquery element
-  // unwrap it if passed
-  if (parent.get) {
-    parent = parent.get(0);
-  }
-
-  // support selector
-  if (isString(parent)) {
-    parent = domQuery(parent);
-  }
-
-  var container = this.container = domify('<div class="bjs-container"></div>');
-  parent.appendChild(container);
-
-  assign(container.style, {
-    width: ensureUnit(options.width),
-    height: ensureUnit(options.height),
-    position: options.position
-  });
 
   /* <project-logo> */
 
-  addProjectLogo(container);
+  addProjectLogo(this.container);
 
   /* </project-logo> */
+
+  this._init(this.container, this.moddle, options);
 }
 
+inherits(Viewer, Diagram);
+
 module.exports = Viewer;
 
 
@@ -206,10 +185,6 @@ Viewer.prototype.saveXML = function(options, done) {
   this.moddle.toXML(definitions, options, done);
 };
 
-Viewer.prototype.createModdle = function() {
-  return new BpmnModdle(assign({}, this._moddleExtensions, this.options.moddleExtensions));
-};
-
 /**
  * Export the currently displayed BPMN 2.0 diagram as
  * an SVG image.
@@ -258,15 +233,9 @@ Viewer.prototype.saveSVG = function(options, done) {
  * @param {String} name
  *
  * @return {Object} diagram service instance
+ *
+ * @method Viewer#get
  */
-Viewer.prototype.get = function(name) {
-
-  if (!this.diagram) {
-    throw new Error('no diagram loaded');
-  }
-
-  return this.diagram.get(name);
-};
 
 /**
  * Invoke a function in the context of this viewer.
@@ -280,94 +249,61 @@ Viewer.prototype.get = function(name) {
  * @param {Function} fn to be invoked
  *
  * @return {Object} the functions return value
+ *
+ * @method Viewer#invoke
  */
-Viewer.prototype.invoke = function(fn) {
-
-  if (!this.diagram) {
-    throw new Error('no diagram loaded');
-  }
-
-  return this.diagram.invoke(fn);
-};
-
-Viewer.prototype.importDefinitions = function(definitions, done) {
-
-  // use try/catch to not swallow synchronous exceptions
-  // that may be raised during model parsing
-  try {
-    if (this.diagram) {
-      this.clear();
-    }
-
-    this.definitions = definitions;
-
-    var diagram = this.diagram = this._createDiagram(this.options);
-
-    this._init(diagram);
-
-    Importer.importBpmnDiagram(diagram, definitions, done);
-  } catch (e) {
-    done(e);
-  }
-};
-
-Viewer.prototype._init = function(diagram) {
-  initListeners(diagram, this.__listeners || []);
-};
-
-Viewer.prototype._createDiagram = function(options) {
-
-  var modules = [].concat(options.modules || this.getModules(), options.additionalModules || []);
-
-  // add self as an available service
-  modules.unshift({
-    bpmnjs: [ 'value', this ],
-    moddle: [ 'value', this.moddle ]
-  });
-
-  options = omit(options, 'additionalModules');
-
-  options = assign(options, {
-    canvas: assign({}, options.canvas, { container: this.container }),
-    modules: modules
-  });
-
-  return new Diagram(options);
-};
-
-
-Viewer.prototype.getModules = function() {
-  return this._modules;
-};
 
 /**
  * Remove all drawn elements from the viewer.
  *
  * After calling this method the viewer can still
  * be reused for opening another diagram.
+ *
+ * @method Viewer#clear
  */
-Viewer.prototype.clear = function() {
-  var diagram = this.diagram;
 
-  if (diagram) {
+Viewer.prototype.importDefinitions = function(definitions, done) {
-    diagram.destroy();
+
+  // use try/catch to not swallow synchronous exceptions
+  // that may be raised during model parsing
+  try {
+
+    if (this.definitions) {
+      // clear existing rendered diagram
+      this.clear();
+    }
+
+    // update definitions
+    this.definitions = definitions;
+
+    // perform graphical import
+    Importer.importBpmnDiagram(this, definitions, done);
+  } catch (e) {
+
+    // handle synchronous errors
+    done(e);
   }
 };
 
+Viewer.prototype.getModules = function() {
+  return this._modules;
+};
+
 /**
- * Destroy the viewer instance and remove all its remainders
+ * Destroy the viewer instance and remove all its
- * from the document tree.
+ * remainders from the document tree.
  */
 Viewer.prototype.destroy = function() {
-  // clear underlying diagram
-  this.clear();
 
-  // remove container
+  // diagram destroy
+  Diagram.prototype.destroy.call(this);
+
+  // dom detach
   domRemove(this.container);
 };
 
 /**
- * Register an event listener on the viewer
+ * Register an event listener
  *
  * Remove a previously added listener via {@link #off(event, callback)}.
  *
@@ -376,50 +312,79 @@ Viewer.prototype.destroy = function() {
  * @param {Function} callback
  * @param {Object} [that]
  */
-Viewer.prototype.on = function(event, priority, callback, that) {
+Viewer.prototype.on = function(event, priority, callback, target) {
-  var diagram = this.diagram,
+  return this.get('eventBus').on(event, priority, callback, target);
-      listeners = this.__listeners = this.__listeners || [];
-
-  if (typeof priority === 'function') {
-    that = callback;
-    callback = priority;
-    priority = 1000;
-  }
-
-  listeners.push({ event: event, priority: priority, callback: callback, that: that });
-
-  if (diagram) {
-    return diagram.get('eventBus').on(event, priority, callback, that);
-  }
 };
 
 /**
- * De-register an event callback
+ * De-register an event listener
  *
  * @param {String} event
  * @param {Function} callback
  */
 Viewer.prototype.off = function(event, callback) {
-  var filter,
+  this.get('eventBus').off(event, callback);
-      diagram = this.diagram;
-
-  if (callback) {
-    filter = function(l) {
-      return !(l.event === event && l.callback === callback);
-    };
-  } else {
-    filter = function(l) {
-      return l.event !== event;
-    };
-  }
-
-  this.__listeners = (this.__listeners || []).filter(filter);
-
-  if (diagram) {
-    diagram.get('eventBus').off(event, callback);
-  }
 };
 
+
+Viewer.prototype._init = function(container, moddle, options) {
+
+  var baseModules = options.modules || this.getModules(),
+      additionalModules = options.additionalModules || [],
+      staticModules = [
+        {
+          bpmnjs: [ 'value', this ],
+          moddle: [ 'value', moddle ]
+        }
+      ];
+
+  var diagramModules = [].concat(staticModules, baseModules, additionalModules);
+
+  var diagramOptions = assign(omit(options, 'additionalModules'), {
+    canvas: assign({}, options.canvas, { container: container }),
+    modules: diagramModules
+  });
+
+  // invoke diagram constructor
+  Diagram.call(this, diagramOptions);
+};
+
+Viewer.prototype._createContainer = function(options) {
+
+  var parent = options.container,
+      container;
+
+  // support jquery element
+  // unwrap it if passed
+  if (parent.get) {
+    parent = parent.get(0);
+  }
+
+  // support selector
+  if (isString(parent)) {
+    parent = domQuery(parent);
+  }
+
+  container = domify('<div class="bjs-container"></div>');
+
+  assign(container.style, {
+    width: ensureUnit(options.width),
+    height: ensureUnit(options.height),
+    position: options.position
+  });
+
+  parent.appendChild(container);
+
+  return container;
+};
+
+Viewer.prototype._createModdle = function(options) {
+  var moddleOptions = assign({}, this._moddleExtensions, options.moddleExtensions);
+
+  return new BpmnModdle(moddleOptions);
+};
+
+
 // modules the viewer is composed of
 Viewer.prototype._modules = [
   require('./core'),

test/spec/ModelerSpec.js

@@ -107,37 +107,6 @@ describe('Modeler', function() {
   });
 
 
-  describe('ids', function() {
-
-    it('should populate ids on import', function(done) {
-
-      // given
-      var xml = require('../fixtures/bpmn/simple.bpmn');
-
-      var modeler = new Modeler({ container: container });
-
-
-      // when
-      modeler.importXML(xml, function(err) {
-
-        var moddle = modeler.get('moddle');
-        var elementRegistry = modeler.get('elementRegistry');
-
-        var subProcess = elementRegistry.get('SubProcess_1').businessObject;
-        var bpmnEdge = elementRegistry.get('SequenceFlow_3').businessObject.di;
-
-        // then
-        expect(moddle.ids.assigned('SubProcess_1')).to.eql(subProcess);
-        expect(moddle.ids.assigned('BPMNEdge_SequenceFlow_3')).to.eql(bpmnEdge);
-
-        done();
-      });
-
-    });
-
-  });
-
-
   describe('translate support', function() {
 
     var xml = require('../fixtures/bpmn/simple.bpmn');
@@ -275,6 +244,81 @@ describe('Modeler', function() {
   });
 
 
+  describe('ids', function() {
+
+    it('should provide ids with moddle', function() {
+
+      // given
+      var modeler = new Modeler({ container: container });
+
+      // when
+      var moddle = modeler.get('moddle');
+
+      // then
+      expect(moddle.ids).to.exist;
+    });
+
+
+    it('should populate ids on import', function(done) {
+
+      // given
+      var xml = require('../fixtures/bpmn/simple.bpmn');
+
+      var modeler = new Modeler({ container: container });
+
+      var moddle = modeler.get('moddle');
+      var elementRegistry = modeler.get('elementRegistry');
+
+      // when
+      modeler.importXML(xml, function(err) {
+
+        var subProcess = elementRegistry.get('SubProcess_1').businessObject;
+        var bpmnEdge = elementRegistry.get('SequenceFlow_3').businessObject.di;
+
+        // then
+        expect(moddle.ids.assigned('SubProcess_1')).to.eql(subProcess);
+        expect(moddle.ids.assigned('BPMNEdge_SequenceFlow_3')).to.eql(bpmnEdge);
+
+        done();
+      });
+
+    });
+
+
+    it('should clear ids before re-import', function(done) {
+
+      // given
+      var someXML = require('../fixtures/bpmn/simple.bpmn'),
+          otherXML = require('../fixtures/bpmn/basic.bpmn');
+
+      var modeler = new Modeler({ container: container });
+
+      var moddle = modeler.get('moddle');
+      var elementRegistry = modeler.get('elementRegistry');
+
+      // when
+      modeler.importXML(someXML, function() {
+
+        modeler.importXML(otherXML, function() {
+
+          var task = elementRegistry.get('Task_1').businessObject;
+
+          // then
+          // not in other.bpmn
+          expect(moddle.ids.assigned('SubProcess_1')).to.be.false;
+
+          // in other.bpmn
+          expect(moddle.ids.assigned('Task_1')).to.eql(task);
+
+          done();
+        });
+      });
+
+    });
+
+  });
+
+
   it('should handle errors', function(done) {
 
     var xml = 'invalid stuff';
@@ -298,7 +342,7 @@ describe('Modeler', function() {
 
   describe('dependency injection', function() {
 
-    it('should be available via di as <bpmnjs>', function(done) {
+    it('should provide self as <bpmnjs>', function(done) {
 
       var xml = require('../fixtures/bpmn/simple.bpmn');
 
@@ -310,6 +354,49 @@ describe('Modeler', function() {
       });
     });
 
+
+    it('should allow Diagram#get before import', function() {
+
+      // when
+      var modeler = new Modeler({ container: container });
+
+      // then
+      var eventBus = modeler.get('eventBus');
+
+      expect(eventBus).to.exist;
+    });
+
+
+    it('should keep references to services across re-import', function(done) {
+
+      // given
+      var someXML = require('../fixtures/bpmn/simple.bpmn'),
+          otherXML = require('../fixtures/bpmn/basic.bpmn');
+
+      var modeler = new Modeler({ container: container });
+
+      var eventBus = modeler.get('eventBus'),
+          canvas = modeler.get('canvas');
+
+      // when
+      modeler.importXML(someXML, function() {
+
+        // then
+        expect(modeler.get('canvas')).to.equal(canvas);
+        expect(modeler.get('eventBus')).to.equal(eventBus);
+
+        modeler.importXML(otherXML, function() {
+
+          // then
+          expect(modeler.get('canvas')).to.equal(canvas);
+          expect(modeler.get('eventBus')).to.equal(eventBus);
+
+          done();
+        });
+      });
+
+    });
+
   });
 
 });

test/spec/ViewerSpec.js

@@ -2,6 +2,8 @@
 
 var TestContainer = require('mocha-test-container-support');
 
+var Diagram = require('diagram-js/lib/Diagram');
+
 var Viewer = require('../../lib/Viewer');
 
 var inherits = require('inherits');
@@ -46,8 +48,11 @@ describe('Viewer', function() {
       // mimic re-import of same diagram
       viewer.importXML(xml, function(err, warnings) {
 
+        if (err) {
+          return done(err);
+        }
+
         // then
-        expect(err).to.exist;
         expect(warnings.length).to.equal(0);
 
         done();
@@ -57,6 +62,16 @@ describe('Viewer', function() {
   });
 
 
+  it('should be instance of Diagram', function() {
+
+    // when
+    var viewer = new Viewer({ container: container });
+
+    // then
+    expect(viewer).to.be.instanceof(Diagram);
+  });
+
+
   describe('defaults', function() {
 
     it('should use <body> as default parent', function(done) {
@@ -259,7 +274,7 @@ describe('Viewer', function() {
 
   describe('dependency injection', function() {
 
-    it('should be available via di as <bpmnjs>', function(done) {
+    it('should provide self as <bpmnjs>', function(done) {
 
       var xml = require('../fixtures/bpmn/simple.bpmn');
 
@@ -271,6 +286,48 @@ describe('Viewer', function() {
       });
     });
 
+
+    it('should allow Diagram#get before import', function() {
+
+      // when
+      var viewer = new Viewer({ container: container });
+
+      // then
+      var eventBus = viewer.get('eventBus');
+
+      expect(eventBus).to.exist;
+    });
+
+
+    it('should keep references to services across re-import', function(done) {
+
+      // given
+      var someXML = require('../fixtures/bpmn/simple.bpmn'),
+          otherXML = require('../fixtures/bpmn/basic.bpmn');
+
+      var viewer = new Viewer({ container: container });
+
+      var eventBus = viewer.get('eventBus'),
+          canvas = viewer.get('canvas');
+
+      // when
+      viewer.importXML(someXML, function() {
+
+        // then
+        expect(viewer.get('canvas')).to.equal(canvas);
+        expect(viewer.get('eventBus')).to.equal(eventBus);
+
+        viewer.importXML(otherXML, function() {
+
+          // then
+          expect(viewer.get('canvas')).to.equal(canvas);
+          expect(viewer.get('eventBus')).to.equal(eventBus);
+
+          done();
+        });
+      });
+
+    });
   });