[ONOS-4650][ONOS-4726][ONOS-4727] [ONOS-4728]Implement must parser + when parser + feature + if-feature + revision defect fix
Change-Id: I0a3aee6c1c6b72ef7da7f7f565fd0f149fe3fd42
diff --git a/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/MustListener.java b/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/MustListener.java
new file mode 100644
index 0000000..b6cbf20
--- /dev/null
+++ b/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/MustListener.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2016-present 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.YangMust;
+import org.onosproject.yangutils.datamodel.YangMustHolder;
+import org.onosproject.yangutils.datamodel.utils.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.YangConstructType.MUST_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_CURRENT_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.removeQuotesAndHandleConcat;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *
+ * must-stmt = must-keyword sep string optsep
+ * (";" /
+ * "{" stmtsep
+ * ;; these stmts can appear in any order
+ * [error-message-stmt stmtsep]
+ * [error-app-tag-stmt stmtsep]
+ * [description-stmt stmtsep]
+ * [reference-stmt stmtsep]
+ * "}")
+ *
+ * ANTLR grammar rule
+ * mustStatement : MUST_KEYWORD string (STMTEND | LEFT_CURLY_BRACE commonStatements RIGHT_CURLY_BRACE);
+ */
+
+/**
+ * Represents listener based call back function corresponding to the
+ * "must" rule defined in ANTLR grammar file for corresponding ABNF rule
+ * in RFC 6020.
+ */
+public final class MustListener {
+
+ /**
+ * Creates a new must listener.
+ */
+ private MustListener() {
+ }
+
+ /**
+ * Perform validations and updates the data model tree.It is called when parser
+ * receives an input matching the grammar rule (must).
+ *
+ * @param listener listener's object
+ * @param ctx context object of the grammar rule
+ */
+ public static void processMustEntry(TreeWalkListener listener,
+ GeneratedYangParser.MustStatementContext ctx) {
+
+ // Check for stack to be non empty.
+ checkStackIsNotEmpty(listener, MISSING_HOLDER, MUST_DATA, ctx.string().getText(), ENTRY);
+ String constraint = removeQuotesAndHandleConcat(ctx.string().getText());
+
+ // Obtain the node of the stack.
+ Parsable tmpNode = listener.getParsedDataStack().peek();
+ if (tmpNode instanceof YangMustHolder) {
+
+ YangMust must = new YangMust();
+ must.setConstraint(constraint);
+
+ YangMustHolder mustHolder = (YangMustHolder) tmpNode;
+ mustHolder.addMust(must);
+
+ listener.getParsedDataStack().push(must);
+ } else {
+ throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, MUST_DATA,
+ ctx.string().getText(), ENTRY));
+ }
+
+ }
+
+ /**
+ * Performs validation and updates the data model tree.It is called when parser
+ * exits from grammar rule (must).
+ *
+ * @param listener listener's object
+ * @param ctx context object of the grammar rule
+ */
+ public static void processMustExit(TreeWalkListener listener,
+ GeneratedYangParser.MustStatementContext ctx) {
+
+ // Check for stack to be non empty.
+ checkStackIsNotEmpty(listener, MISSING_HOLDER, MUST_DATA, ctx.string().getText(), EXIT);
+
+ if (listener.getParsedDataStack().peek() instanceof YangMust) {
+ listener.getParsedDataStack().pop();
+ } else {
+ throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, MUST_DATA,
+ ctx.string().getText(), EXIT));
+ }
+ }
+}