YANG string restriction listener + YANG Range restriction listener review comment fix

Change-Id: I9e7af9c67f8fbf918d4e0d8ff147a560889ff264
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PatternRestrictionListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PatternRestrictionListener.java
new file mode 100644
index 0000000..b06ecb5
--- /dev/null
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PatternRestrictionListener.java
@@ -0,0 +1,134 @@
+/*
+ * 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.YangDerivedInfo;
+import org.onosproject.yangutils.datamodel.YangType;
+import org.onosproject.yangutils.datamodel.YangStringRestriction;
+import org.onosproject.yangutils.datamodel.YangDataTypes;
+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 org.onosproject.yangutils.utils.YangConstructType;
+
+import static org.onosproject.yangutils.utils.YangConstructType.PATTERN_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.TYPE_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.ListenerValidation.checkStackIsNotEmpty;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *  pattern-stmt        = pattern-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
+ *  patternStatement : PATTERN_KEYWORD string (STMTEND | LEFT_CURLY_BRACE commonStatements RIGHT_CURLY_BRACE);
+ */
+
+/**
+ * Represents listener based call back function corresponding to the "pattern"
+ * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ */
+public final class PatternRestrictionListener {
+
+    private static final String EMPTY_STRING = "";
+
+    /**
+     * Creates a new pattern restriction listener.
+     */
+    private PatternRestrictionListener() {
+    }
+
+    /**
+     * It is called when parser receives an input matching the grammar
+     * rule (pattern), performs validation and updates the data model
+     * tree.
+     *
+     * @param listener listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processPatternRestrictionEntry(TreeWalkListener listener,
+                                        GeneratedYangParser.PatternStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, PATTERN_DATA, ctx.string().getText(), ENTRY);
+
+        Parsable tmpData = listener.getParsedDataStack().peek();
+        if (tmpData.getYangConstructType() == TYPE_DATA) {
+            YangType type = (YangType) tmpData;
+            setPatternRestriction(type, ctx);
+        } else {
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, PATTERN_DATA,
+                    ctx.string().getText(), ENTRY));
+        }
+    }
+
+    /**
+     * Sets the pattern restriction to type.
+     *
+     * @param type Yang type for which pattern restriction to be set
+     * @param ctx context object of the grammar rule
+     */
+    private static void setPatternRestriction(YangType type,
+                                              GeneratedYangParser.PatternStatementContext ctx) {
+
+        YangStringRestriction stringRestriction;
+
+        if (type.getDataType() != YangDataTypes.STRING && type.getDataType() != YangDataTypes.DERIVED) {
+
+            ParserException parserException = new ParserException("YANG file error : " +
+                    YangConstructType.getYangConstructType(PATTERN_DATA) + " name " + ctx.string().getText() +
+                    " can be used to restrict the built-in type string or types derived from string.");
+            parserException.setLine(ctx.getStart().getLine());
+            parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
+            throw parserException;
+        }
+
+        if (type.getDataType() == YangDataTypes.STRING) {
+            stringRestriction = (YangStringRestriction) type.getDataTypeExtendedInfo();
+        } else {
+            stringRestriction = (YangStringRestriction) ((YangDerivedInfo<?>) type
+                    .getDataTypeExtendedInfo()).getExtendedInfo();
+        }
+
+        if (stringRestriction == null) {
+            stringRestriction = new YangStringRestriction();
+            if (type.getDataType() == YangDataTypes.STRING) {
+                type.setDataTypeExtendedInfo(stringRestriction);
+            } else {
+                ((YangDerivedInfo<YangStringRestriction>) type.getDataTypeExtendedInfo())
+                        .setExtendedInfo(stringRestriction);
+            }
+        }
+
+        String patternArgument = ctx.string().getText().replace("\"", EMPTY_STRING);
+        stringRestriction.addPattern(patternArgument);
+    }
+}