YANG rpc, input and output listener
Change-Id: Idd9847175c61d9f033cf80213b46e9c9c949849c
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OutputListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OutputListener.java
new file mode 100644
index 0000000..19f39e8
--- /dev/null
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OutputListener.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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 org.onosproject.yangutils.parser.impl.listeners;
+
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.datamodel.YangOutput;
+import org.onosproject.yangutils.datamodel.YangRpc;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+
+import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
+import static org.onosproject.yangutils.datamodel.utils.YangDataModelFactory.getYangOutputNode;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructExtendedListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+import static org.onosproject.yangutils.utils.YangConstructType.OUTPUT_DATA;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *
+ * output-stmt = output-keyword optsep
+ * "{" stmtsep
+ * ;; these stmts can appear in any order
+ * *((typedef-stmt /
+ * grouping-stmt) stmtsep)
+ * 1*(data-def-stmt stmtsep)
+ * "}"
+ *
+ * outputStatement : OUTPUT_KEYWORD LEFT_CURLY_BRACE outputStatementBody RIGHT_CURLY_BRACE;
+
+ * outputStatementBody : typedefStatement* dataDefStatement+
+ * | dataDefStatement+ typedefStatement*
+ * | groupingStatement* dataDefStatement+
+ * | dataDefStatement+ groupingStatement*;
+ */
+
+/**
+ * Implements listener based call back function corresponding to the "output"
+ * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ */
+public final class OutputListener {
+
+ private static final String OUTPUT_KEYWORD = "Output";
+
+ /**
+ * Creates a new output listener.
+ */
+ private OutputListener() {
+ }
+
+ /**
+ * It is called when parser receives an input matching the grammar rule
+ * (output), performs validation and updates the data model tree.
+ *
+ * @param listener listener's object
+ * @param ctx context object of the grammar rule
+ */
+ public static void processOutputEntry(TreeWalkListener listener,
+ GeneratedYangParser.OutputStatementContext ctx) {
+
+ // Check for stack to be non empty.
+ checkStackIsNotEmpty(listener, MISSING_HOLDER, OUTPUT_DATA, "", ENTRY);
+
+ Parsable curData = listener.getParsedDataStack().peek();
+ if (curData instanceof YangRpc) {
+
+ YangOutput yangOutput = getYangOutputNode(JAVA_GENERATION);
+ yangOutput.setName(((YangRpc) curData).getName() + OUTPUT_KEYWORD);
+ YangNode curNode = (YangNode) curData;
+ try {
+ curNode.addChild(yangOutput);
+ } catch (DataModelException e) {
+ throw new ParserException(constructExtendedListenerErrorMessage(UNHANDLED_PARSED_DATA,
+ OUTPUT_DATA, "", ENTRY, e.getMessage()));
+ }
+ listener.getParsedDataStack().push(yangOutput);
+ } else {
+ throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, OUTPUT_DATA,
+ "", ENTRY));
+ }
+ }
+
+ /**
+ * It is called when parser exits from grammar rule (output), it perform
+ * validations and updates the data model tree.
+ *
+ * @param listener listener's object
+ * @param ctx context object of the grammar rule
+ */
+ public static void processOutputExit(TreeWalkListener listener,
+ GeneratedYangParser.OutputStatementContext ctx) {
+
+ // Check for stack to be non empty.
+ checkStackIsNotEmpty(listener, MISSING_HOLDER, OUTPUT_DATA, "", EXIT);
+
+ if (!(listener.getParsedDataStack().peek() instanceof YangOutput)) {
+ throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, OUTPUT_DATA,
+ "", EXIT));
+ }
+ listener.getParsedDataStack().pop();
+ }
+}
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