Merge pull request #108 from konarshankar07/backend-model-completion--task-89

#89 : Completion. Add PHP classes completion to the backend_model attribute and tag

Author: Vitaliy

src/com/magento/idea/magento2plugin/completion/xml/XmlCompletionContributor.java

@@ -118,6 +118,19 @@ public XmlCompletionContributor() {
                 new PhpClassCompletionProvider()
         );
 
+        // <backend_model>completion</backend_model>
+        extend(CompletionType.BASIC,
+                psiElement(XmlTokenType.XML_DATA_CHARACTERS)
+                        .inside(XmlPatterns.xmlTag().withName(ModuleSystemXml.XML_TAG_BACKEND_MODEL)),
+                new PhpClassCompletionProvider()
+        );
+
+        // <randomTag backend_model="completion">
+        extend(CompletionType.BASIC, psiElement(XmlTokenType.XML_ATTRIBUTE_VALUE_TOKEN)
+                        .inside(XmlPatterns.xmlAttribute().withName(ModuleConfigXml.XML_ATTRIBUTE_BACKEND_MODEL)),
+                new PhpClassCompletionProvider()
+        );
+
         // <parameter source_model="completion">...</parameter> in widget.xml files.
         extend(CompletionType.BASIC, psiElement(XmlTokenType.XML_ATTRIBUTE_VALUE_TOKEN)
             .inside(XmlPatterns.xmlAttribute().withName(ModuleWidgetXml.ATTRIBUTE_SOURCE_MODEL_NAME)

src/com/magento/idea/magento2plugin/magento/files/ModuleConfigXml.java

@@ -0,0 +1,9 @@
+/*
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+package com.magento.idea.magento2plugin.magento.files;
+
+public class ModuleConfigXml {
+    public static final String XML_ATTRIBUTE_BACKEND_MODEL = "backend_model";
+}

src/com/magento/idea/magento2plugin/magento/files/ModuleSystemXml.java

@@ -9,4 +9,5 @@ public class ModuleSystemXml {
     public static final String FIELD_ELEMENT_NAME = "field";
     public static final String XML_TAG_SOURCE_MODEL = "source_model";
     public static final String XML_TAG_FRONTEND_MODEL = "frontend_model";
+    public static final String XML_TAG_BACKEND_MODEL = "backend_model";
 }