[ONOS-3906],[ONOS-3910] Implementation of YANG module and leaf/leaf-list translator.

Change-Id: If1a8a991ffafa14b51211f97c435176ee1bf856f
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/CopyrightHeader.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/CopyrightHeader.java
index 8b7e732..3ba2fc6 100644
--- a/src/main/java/org/onosproject/yangutils/utils/io/impl/CopyrightHeader.java
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/CopyrightHeader.java
@@ -33,9 +33,11 @@
 public final class CopyrightHeader {
 
     private static final Logger log = getLogger(CopyrightHeader.class);
-    private static final int NULL = -1;
+    private static final int EOF = -1;
     private static ClassLoader classLoader = CopyrightHeader.class.getClassLoader();
 
+    private static String copyrightHeader;
+
     /**
      * Default constructor.
      */
@@ -43,21 +45,30 @@
     }
 
     /**
-     * Returns Copyright file header.
+     * Returns copyright file header.
      *
-     * @return Copyright file header
+     * @return copyright file header
+     * @throws IOException when fails to parse copyright header.
      */
-    public static String getCopyrightHeader() {
-        return parseOnosHeader();
+    public static String getCopyrightHeader() throws IOException {
+        return copyrightHeader;
+    }
+
+    /**
+     * Sets the copyright header.
+     *
+     * @param header copyright header
+     */
+    private static void setCopyrightHeader(String header) {
+        copyrightHeader = header;
     }
 
     /**
      * parse Copyright to the temporary file.
      *
-     * @param file generated file
-     * @param stream input stream
+     * @throws IOException when fails to get the copyright header.
      */
-    private static String parseOnosHeader() {
+    public static void parseCopyrightHeader() throws IOException {
 
         File temp = new File("temp.txt");
 
@@ -65,17 +76,18 @@
             InputStream stream = classLoader.getResourceAsStream("CopyrightHeader.txt");
             OutputStream out = new FileOutputStream(temp);
             int index;
-            while ((index = stream.read()) != NULL) {
+            while ((index = stream.read()) != EOF) {
                 out.write(index);
             }
             out.close();
-            return convertToString(temp.toString());
+            stream.close();
+            getStringFileContent(temp);
+            setCopyrightHeader(getStringFileContent(temp));
         } catch (IOException e) {
-            log.info("Failed to insert onos header in files.");
+            throw new IOException("failed to parse the Copyright header");
         } finally {
             temp.delete();
         }
-        return "";
     }
 
     /**
@@ -85,7 +97,8 @@
      * @return string of file.
      * @throws IOException when fails to convert to string
      */
-    private static String convertToString(String toAppend) throws IOException {
+    private static String getStringFileContent(File toAppend) throws IOException {
+
         BufferedReader bufferReader = new BufferedReader(new FileReader(toAppend));
         try {
             StringBuilder stringBuilder = new StringBuilder();
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtil.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtil.java
new file mode 100644
index 0000000..f7e3556
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtil.java
@@ -0,0 +1,150 @@
+/*
+ * 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.utils.io.impl;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import org.onosproject.yangutils.translator.CachedFileHandle;
+import org.onosproject.yangutils.translator.GeneratedFileType;
+import org.onosproject.yangutils.translator.tojava.CachedJavaFileHandle;
+import org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax;
+import org.onosproject.yangutils.utils.UtilConstants;
+
+/**
+ * Utility to handle file system operations.
+ */
+public final class FileSystemUtil {
+    /**
+     * Hiding constructor of a utility class.
+     */
+    private FileSystemUtil() {
+    }
+
+    /**
+     * Check if the package directory structure created.
+     *
+     * @param pkg Package to check if it is created.
+     * @return existence status of package.
+     */
+    public static boolean doesPackageExist(File pkg) {
+        if (pkg.exists()) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Create a package structure with package info java file if not present.
+     *
+     * @param pkg java package string
+     * @param pkgInfo description of package
+     * @throws IOException any IO exception
+     */
+    public static void createPackage(String pkg, String pkgInfo) throws IOException {
+        if (!doesPackageExist(new File(pkg))) {
+            try {
+                File pack = YangIoUtils
+                        .createDirectories(pkg.replace(UtilConstants.PERIOD, UtilConstants.SLASH));
+                YangIoUtils.addPackageInfo(pack, pkgInfo, pkg);
+            } catch (IOException e) {
+                throw new IOException("failed to create package-info file");
+            }
+        }
+    }
+
+    /**
+     * Create a java source file in the specified package.
+     *
+     * @param pkg java package under which the interface file needs to be created.
+     * @param yangName YANG name of the node for which java file needs to be created.
+     * @param types types of files to be created.
+     * @throws IOException when fails to create interface file.
+     * @return the cached java file handle, which can be used to further add methods.
+     */
+    public static CachedFileHandle createSourceFiles(String pkg, String yangName, GeneratedFileType types)
+            throws IOException {
+        //if (!doesPackageExist(new File(pkg))) {
+        //    throw new IOException("package does not exist.");
+        //}
+        yangName = JavaIdentifierSyntax.getCamelCase(yangName);
+        CachedFileHandle handler = new CachedJavaFileHandle(pkg, yangName, types);
+
+        return handler;
+    }
+
+    /**
+     * Read the contents from source file and append its contents to append
+     * file.
+     *
+     * @param toAppend destination file in which the contents of source file is
+     *            appended.
+     * @param srcFile source file from which data is read and added to to append
+     *            file.
+     * @throws IOException any IO errors.
+     */
+    public static void appendFileContents(File toAppend, File srcFile) throws IOException {
+
+        insertStringInFile(srcFile, UtilConstants.NEW_LINE + readAppendFile(toAppend.toString()));
+        //TODO: read the contents from src file and append its contents to append file.
+        return;
+    }
+
+    /**
+     * Reads file and convert it to string.
+     *
+     * @param toAppend file to be converted.
+     * @return string of file.
+     * @throws IOException when fails to convert to string
+     */
+    private static String readAppendFile(String toAppend) throws IOException {
+        BufferedReader bufferReader = new BufferedReader(new FileReader(toAppend));
+        try {
+            StringBuilder stringBuilder = new StringBuilder();
+            String line = bufferReader.readLine();
+
+            while (line != null) {
+                stringBuilder.append(UtilConstants.FOUR_SPACE_INDENTATION + line);
+                stringBuilder.append("\n");
+                line = bufferReader.readLine();
+            }
+            return stringBuilder.toString();
+        } finally {
+            bufferReader.close();
+        }
+    }
+
+    /**
+     * Insert content to the generated file.
+     *
+     * @param inputFile input file
+     * @param contentTobeAdded content to be appended to the file.
+     * @throws IOException when fails to append content to the file.
+     */
+    public static void insertStringInFile(File inputFile, String contentTobeAdded) throws IOException {
+        FileWriter fileWriter = new FileWriter(inputFile, true);
+        PrintWriter outputPrintWriter = new PrintWriter(fileWriter);
+        outputPrintWriter.write(contentTobeAdded);
+        outputPrintWriter.flush();
+        outputPrintWriter.close();
+
+    }
+}
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java
new file mode 100644
index 0000000..635acf1
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java
@@ -0,0 +1,250 @@
+/*
+ * 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.utils.io.impl;
+
+import org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax;
+import org.onosproject.yangutils.utils.UtilConstants;
+
+/**
+ * Provides javadoc for the generated classes.
+ */
+public final class JavaDocGen {
+
+    /**
+     * Default Constructor.
+     */
+    private JavaDocGen() {
+    }
+
+    /**
+     * JavaDocs types.
+     */
+    public static enum JavaDocType {
+
+        /**
+         * For class.
+         */
+        IMPL_CLASS,
+
+        /**
+         * For builder class.
+         */
+        BUILDER_CLASS,
+
+        /**
+         * For interface.
+         */
+        INTERFACE,
+
+        /**
+         * For builder interface.
+         */
+        BUILDER_INTERFACE,
+
+        /**
+         * For package-info.
+         */
+        PACKAGE_INFO,
+
+        /**
+         * For getters.
+         */
+        GETTER,
+
+        /**
+         * For setters.
+         */
+        SETTER,
+
+        /**
+         * For default constructor.
+         */
+        DEFAULT_CONSTRUCTOR,
+
+        /**
+         * For constructor.
+         */
+        CONSTRUCTOR,
+
+        /**
+         * For build.
+         */
+        BUILD
+    }
+
+    /**
+     * Returns java docs.
+     *
+     * @param type java doc type
+     * @param name name of the YangNode
+     * @return javadocs.
+     */
+    public static String getJavaDoc(JavaDocType type, String name) {
+        name = JavaIdentifierSyntax.getCamelCase(name);
+        String javaDoc = "";
+        if (type.equals(JavaDocType.IMPL_CLASS)) {
+            javaDoc = generateForImplClass(name);
+        } else if (type.equals(JavaDocType.BUILDER_CLASS)) {
+            javaDoc = generateForBuilderClass(name);
+        } else if (type.equals(JavaDocType.INTERFACE)) {
+            javaDoc = generateForInterface(name);
+        } else if (type.equals(JavaDocType.BUILDER_INTERFACE)) {
+            javaDoc = generateForBuilderInterface(name);
+        } else if (type.equals(JavaDocType.PACKAGE_INFO)) {
+            javaDoc = generateForPackage(name);
+        } else if (type.equals(JavaDocType.GETTER)) {
+            javaDoc = generateForGetters(name);
+        } else if (type.equals(JavaDocType.SETTER)) {
+            javaDoc = generateForSetters(name);
+        } else if (type.equals(JavaDocType.DEFAULT_CONSTRUCTOR)) {
+            javaDoc = generateForDefaultConstructors();
+        } else if (type.equals(JavaDocType.BUILD)) {
+            javaDoc = generateForBuild(name);
+        } else if (type.equals(JavaDocType.CONSTRUCTOR)) {
+            javaDoc = generateForConstructors(name);
+        }
+        return javaDoc;
+    }
+
+    /**
+     * Generate javaDocs for getter method.
+     *
+     * @param attribute attribute
+     * @return javaDocs
+     */
+    private static String generateForGetters(String attribute) {
+        return (UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_FIRST_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_GETTERS + attribute
+                + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION
+                + UtilConstants.NEW_LINE_ESTRIC + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_RETURN
+                + attribute + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION
+                + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generates javaDocs for setter method.
+     *
+     * @param attribute attribute
+     * @return javaDocs
+     */
+    private static String generateForSetters(String attribute) {
+        return (UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_FIRST_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_SETTERS + attribute
+                + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION
+                + UtilConstants.NEW_LINE_ESTRIC + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_PARAM
+                + attribute + UtilConstants.SPACE + attribute + UtilConstants.NEW_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_RETURN + UtilConstants.BUILDER_OBJECT
+                + attribute + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION
+                + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for the impl class.
+     *
+     * @param className class name
+     * @return javaDocs.
+     */
+    private static String generateForImplClass(String className) {
+        return (UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.IMPL_CLASS_JAVA_DOC + className + UtilConstants.PERIOD
+                + UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for the builder class.
+     *
+     * @param className class name
+     * @return javaDocs.
+     */
+    private static String generateForBuilderClass(String className) {
+        return (UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.BUILDER_CLASS_JAVA_DOC
+                + className + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDoc for the interface.
+     *
+     * @param interfaceName interface name
+     * @return javaDocs.
+     */
+    private static String generateForInterface(String interfaceName) {
+        return (UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.INTERFACE_JAVA_DOC
+                + interfaceName + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDoc for the builder interface.
+     *
+     * @param builderforName builder for name
+     * @return javaDocs.
+     */
+    private static String generateForBuilderInterface(String builderforName) {
+        return (UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.BUILDER_INTERFACE_JAVA_DOC + builderforName
+                + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for package-info.
+     *
+     * @param packageName package name
+     * @return javaDocs
+     */
+    private static String generateForPackage(String packageName) {
+        return (UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.PACKAGE_INFO_JAVADOC + packageName
+                + UtilConstants.PERIOD + UtilConstants.NEW_LINE + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for default constructor.
+     *
+     * @return javaDocs
+     */
+    private static String generateForDefaultConstructors() {
+        return (UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_DEFAULT_CONSTRUCTOR
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for constructor with parameters.
+     *
+     * @param params list of parameters
+     * @param className class name
+     * @return javaDocs
+     */
+    private static String generateForConstructors(String className) {
+        return (UtilConstants.JAVA_DOC_FIRST_LINE + UtilConstants.FOUR_SPACE_INDENTATION
+                + UtilConstants.JAVA_DOC_SETTERS + className + UtilConstants.PERIOD + UtilConstants.NEW_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.NEW_LINE_ESTRIC
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_PARAM
+                + (className.substring(0, 1).toLowerCase() + className.substring(1)) + UtilConstants.OBJECT
+                + UtilConstants.SPACE + UtilConstants.BUILDER_OBJECT + UtilConstants.SPACE + className
+                + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_END_LINE);
+    }
+
+    /**
+     * Generate javaDocs for build.
+     *
+     * @return javaDocs
+     */
+    private static String generateForBuild(String buildName) {
+        return (UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_FIRST_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_BUILD + buildName + UtilConstants.PERIOD
+                + UtilConstants.NEW_LINE + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.NEW_LINE_ESTRIC
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_RETURN
+                + UtilConstants.JAVA_DOC_BUILD_RETURN + buildName + UtilConstants.PERIOD + UtilConstants.NEW_LINE
+                + UtilConstants.FOUR_SPACE_INDENTATION + UtilConstants.JAVA_DOC_END_LINE);
+    }
+}
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/SerializedDataStore.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/SerializedDataStore.java
new file mode 100644
index 0000000..d33e1fe
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/SerializedDataStore.java
@@ -0,0 +1,203 @@
+/*
+ * 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.utils.io.impl;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInput;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutput;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.util.List;
+
+/**
+ * Provides storage for serialized data while traversing data model tree for code generation.
+ */
+public final class SerializedDataStore {
+
+    /**
+     * Data Store types.
+     */
+    public static enum SerializedDataStoreType {
+
+        /**
+         * Methods.
+         */
+        INTERFACE_METHODS,
+
+        /**
+         * Methods.
+         */
+        BUILDER_METHODS,
+
+        /**
+         * Methods.
+         */
+        BUILDER_INTERFACE_METHODS,
+
+        /**
+         * Methods.
+         */
+        IMPL_METHODS,
+
+        /**
+         * Attributes.
+         */
+        ATTRIBUTE,
+
+        /**
+         * Imports.
+         */
+        IMPORT
+    }
+
+    /**
+     * File name string for serialized files of methods.
+     */
+    private static final String INTERFACE_METHOD_FILE_NAME = "SerializedInterfaceMethodDataStore";
+
+    /**
+     * File name string for serialized files of methods.
+     */
+    private static final String BUILDER_METHOD_FILE_NAME = "SerializedBuilderMethodDataStore";
+
+    /**
+     * File name string for serialized files of methods.
+     */
+    private static final String BUILDER_INTERFACE_METHOD_FILE_NAME = "SerializedBuilderInterfaceMethodDataStore";
+
+    /**
+     * File name string for serialized files of methods.
+     */
+    private static final String IMPL_METHOD_FILE_NAME = "SerializedImplMethodDataStore";
+
+    /**
+     * File name string for serialized files of attributes.
+     */
+    private static final String ATTRIBUTE_FILE_NAME = "SerializedAttributeDataStore";
+
+    /**
+     * File name string for serialized files of imports.
+     */
+    private static final String IMPORT_FILE_NAME = "SerializedImportDataStore";
+
+    /**
+     * File extension of serialized files.
+     */
+    private static final String SERIALIZE_FILE_EXTENSION = ".ser";
+
+    /**
+     * Buffer size.
+     */
+    private static final int BUFFER_SIZE = 8 * 1024;
+
+    /**
+     * Default constructor.
+     */
+    private SerializedDataStore() {
+    }
+
+    /**
+     * Writes specific info to a serialized file.
+     *
+     * @param data data to be stored
+     * @param type type of serialized data store
+     * @throws IOException when fails to create a serialized data file.
+     */
+    public static void setSerializeData(String data, SerializedDataStoreType type) throws IOException {
+
+        String fileName = "";
+        if (type.equals(SerializedDataStoreType.ATTRIBUTE)) {
+            fileName = ATTRIBUTE_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.INTERFACE_METHODS)) {
+            fileName = INTERFACE_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.BUILDER_INTERFACE_METHODS)) {
+            fileName = BUILDER_INTERFACE_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.BUILDER_METHODS)) {
+            fileName = BUILDER_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.IMPL_METHODS)) {
+            fileName = IMPL_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.IMPORT)) {
+            fileName = IMPORT_FILE_NAME;
+        } else {
+            throw new IOException("Unresolved file type.");
+        }
+
+        try {
+            OutputStream file = new FileOutputStream(fileName + SERIALIZE_FILE_EXTENSION);
+            OutputStream buffer = new BufferedOutputStream(file, BUFFER_SIZE);
+
+            ObjectOutput output = new ObjectOutputStream(buffer);
+            try {
+                output.writeObject(data);
+            } finally {
+                output.close();
+            }
+        } catch (IOException ex) {
+            throw new IOException("failed to serialize data");
+        }
+    }
+
+    /**
+     * Get the serialized data.
+     *
+     * @param type type of serialized data store
+     * @return list of attribute info.
+     * @throws IOException when fails to read from the file.
+     * @throws ClassNotFoundException when file is missing.
+     */
+    @SuppressWarnings("unchecked")
+    public static List<String> getSerializeData(SerializedDataStoreType type)
+            throws IOException, ClassNotFoundException {
+
+        String fileName = "";
+        if (type.equals(SerializedDataStoreType.ATTRIBUTE)) {
+            fileName = ATTRIBUTE_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.INTERFACE_METHODS)) {
+            fileName = INTERFACE_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.BUILDER_INTERFACE_METHODS)) {
+            fileName = BUILDER_INTERFACE_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.BUILDER_METHODS)) {
+            fileName = BUILDER_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.IMPL_METHODS)) {
+            fileName = IMPL_METHOD_FILE_NAME;
+        } else if (type.equals(SerializedDataStoreType.IMPORT)) {
+            fileName = IMPORT_FILE_NAME;
+        } else {
+            throw new IOException("Unresolved file type.");
+        }
+
+        try {
+            InputStream file = new FileInputStream(fileName + SERIALIZE_FILE_EXTENSION);
+            InputStream buffer = new BufferedInputStream(file);
+            ObjectInput input = new ObjectInputStream(buffer);
+            try {
+                List<String> recoveredData = (List<String>) input.readObject();
+                return recoveredData;
+            } finally {
+                input.close();
+            }
+        } catch (ClassNotFoundException ex) {
+            throw new ClassNotFoundException("failed to fetch the serialized data file.");
+        }
+    }
+}
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/YangFileScanner.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/YangFileScanner.java
index ca5da57..a9006d2 100644
--- a/src/main/java/org/onosproject/yangutils/utils/io/impl/YangFileScanner.java
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/YangFileScanner.java
@@ -34,14 +34,39 @@
     }
 
     /**
-     * Returns the list of yang files.
+     * Returns the list of YANG files.
      *
      * @param root specified directory
-     * @return list of yang files.
-     * @throws IOException when files get deleted while performing the operations.
+     * @return list of YANG files.
+     * @throws IOException when files get deleted while performing the
+     *             operations.
      */
     public static List<String> getYangFiles(String root) throws IOException {
+        return getFiles(root, ".yang");
+    }
 
+    /**
+     * Returns the list of java files.
+     *
+     * @param root specified directory
+     * @return list of java files.
+     * @throws IOException when files get deleted while performing the
+     *             operations.
+     */
+    public static List<String> getJavaFiles(String root) throws IOException {
+        return getFiles(root, ".java");
+    }
+
+    /**
+     * Returns the list of required files.
+     *
+     * @param root specified directory
+     * @param extension file extension.
+     * @return list of required files.
+     * @throws IOException when files get deleted while performing the
+     *             operations.
+     */
+    public static List<String> getFiles(String root, String extension) throws IOException {
         List<String> store = new LinkedList<>();
         Stack<String> stack = new Stack<>();
         stack.push(root);
@@ -60,7 +85,7 @@
                         stack.push(current.toString());
                     } else {
                         String yangFile = current.getCanonicalPath();
-                        if (yangFile.endsWith(".yang")) {
+                        if (yangFile.endsWith(extension)) {
                             store.add(yangFile);
                         }
                     }
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/YangIoUtils.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/YangIoUtils.java
new file mode 100644
index 0000000..af83de4
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/YangIoUtils.java
@@ -0,0 +1,129 @@
+/*
+ * 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.utils.io.impl;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.List;
+
+import org.sonatype.plexus.build.incremental.BuildContext;
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.model.Resource;
+
+import org.onosproject.yangutils.utils.UtilConstants;
+
+import static org.slf4j.LoggerFactory.getLogger;
+import org.slf4j.Logger;
+
+/**
+ * Provides common utility functionalities for code generation.
+ */
+public final class YangIoUtils {
+
+    private static final Logger log = getLogger(YangIoUtils.class);
+
+    /**
+     * Default constructor.
+     */
+    private YangIoUtils() {
+    }
+
+    /**
+     * Creates the directory structure.
+     *
+     * @param path directory path
+     * @return directory structure
+     */
+    public static File createDirectories(String path) {
+
+        File generatedDir = new File(UtilConstants.YANG_GEN_DIR + File.separator + path);
+        generatedDir.mkdirs();
+        return generatedDir;
+    }
+
+    /**
+     * Adds package info file for the created directory.
+     *
+     * @param path directory path
+     * @param classInfo class info for the package
+     * @param pack package of the directory
+     * @throws IOException when fails to create package info file.
+     */
+    public static void addPackageInfo(File path, String classInfo, String pack) throws IOException {
+
+        try {
+
+            File packageInfo = new File(path + File.separator + "package-info.java");
+            packageInfo.createNewFile();
+            if (packageInfo.exists()) {
+
+                FileWriter fileWriter = null;
+                BufferedWriter bufferedWriter = null;
+                fileWriter = new FileWriter(packageInfo);
+                bufferedWriter = new BufferedWriter(fileWriter);
+                bufferedWriter.write(CopyrightHeader.getCopyrightHeader());
+                bufferedWriter.write(JavaDocGen.getJavaDoc(JavaDocGen.JavaDocType.PACKAGE_INFO, classInfo));
+                bufferedWriter.write(UtilConstants.PACKAGE + UtilConstants.SPACE + pack + UtilConstants.SEMI_COLAN);
+                bufferedWriter.close();
+            }
+        } catch (IOException e) {
+            throw new IOException("Exception occured while creating package info file.");
+        }
+    }
+
+    /**
+     * Cleans the generated directory if already exist in source folder.
+     *
+     * @param baseDir generated directory in previous build.
+     */
+    public static void clean(String baseDir) {
+        File generatedDirectory = new File(baseDir + File.separator + UtilConstants.YANG_GEN_DIR);
+        if (generatedDirectory.exists()) {
+            List<String> javafiles;
+            try {
+                javafiles = YangFileScanner.getJavaFiles(generatedDirectory.toString());
+                for (String file : javafiles) {
+                    File currentFile = new File(file);
+                    currentFile.delete();
+                }
+            } catch (IOException e) {
+                log.info("Failed to delete the generated files in " + generatedDirectory + " directory");
+            }
+            generatedDirectory.delete();
+        }
+    }
+
+    /**
+     * Adds generated source directory to the compilation root.
+     *
+     * @param source directory
+     * @param project current maven project
+     * @param context current build context
+     */
+    public static void addToSource(String source, MavenProject project, BuildContext context) {
+
+        project.addCompileSourceRoot(source);
+        Resource rsc = new Resource();
+        rsc.setDirectory(source);
+        project.addResource(rsc);
+        context.refresh(project.getBasedir());
+        log.info("Source directory added to compilation root: " + source);
+    }
+
+}