[ONOS-4350] Inter Jar dependency implementation and code restructuring.

Change-Id: Iacac75e4187aed93ce1754c170a9c19707e5b8c3
diff --git a/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java b/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java
new file mode 100644
index 0000000..bb701a6
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+++ b/plugin/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java
@@ -0,0 +1,116 @@
+/*
+ * 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.YangImport;
+import org.onosproject.yangutils.datamodel.YangInclude;
+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.REVISION_DATE_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+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_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.isDateValid;
+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
+ * import-stmt         = import-keyword sep identifier-arg-str optsep
+ *                       "{" stmtsep
+ *                           prefix-stmt stmtsep
+ *                           [revision-date-stmt stmtsep]
+ *                        "}"
+ * include-stmt        = include-keyword sep identifier-arg-str optsep
+ *                             (";" /
+ *                              "{" stmtsep
+ *                                  [revision-date-stmt stmtsep]
+ *                            "}")
+ * revision-date-stmt = revision-date-keyword sep revision-date stmtend
+ *
+ * ANTLR grammar rule
+ * import_stmt : IMPORT_KEYWORD IDENTIFIER LEFT_CURLY_BRACE import_stmt_body
+ *               RIGHT_CURLY_BRACE;
+ * import_stmt_body : prefix_stmt revision_date_stmt?;
+ *
+ * include_stmt : INCLUDE_KEYWORD IDENTIFIER (STMTEND | LEFT_CURLY_BRACE
+ *                revision_date_stmt_body? RIGHT_CURLY_BRACE);
+ *
+ * revision_date_stmt : REVISION_DATE_KEYWORD DATE_ARG STMTEND;
+ *
+ */
+
+/**
+ * Represents listener based call back function corresponding to the
+ * "revision date" rule defined in ANTLR grammar file for corresponding ABNF
+ * rule in RFC 6020.
+ */
+public final class RevisionDateListener {
+
+    /**
+     * Creates a new revision date listener.
+     */
+    private RevisionDateListener() {
+    }
+
+    /**
+     * It is called when parser receives an input matching the grammar rule
+     * (revision date),perform validations and update the data model tree.
+     *
+     * @param listener Listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processRevisionDateEntry(TreeWalkListener listener,
+            GeneratedYangParser.RevisionDateStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, REVISION_DATE_DATA, ctx.dateArgumentString().getText(),
+                ENTRY);
+
+        String date = removeQuotesAndHandleConcat(ctx.dateArgumentString().getText());
+        if (!isDateValid(date)) {
+            ParserException parserException = new ParserException("YANG file error: Input date is not correct");
+            parserException.setLine(ctx.getStart().getLine());
+            parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
+            throw parserException;
+        }
+
+        // Obtain the node of the stack.
+        Parsable tmpNode = listener.getParsedDataStack().peek();
+        switch (tmpNode.getYangConstructType()) {
+            case IMPORT_DATA: {
+                YangImport importNode = (YangImport) tmpNode;
+                importNode.setRevision(date);
+                break;
+            }
+            case INCLUDE_DATA: {
+                YangInclude includeNode = (YangInclude) tmpNode;
+                includeNode.setRevision(date);
+                break;
+            }
+            default:
+                throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, REVISION_DATE_DATA,
+                        ctx.dateArgumentString().getText(), ENTRY));
+        }
+    }
+}
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