Java Based Search Engine

ACKNOWLEDGMENT I express convey and gratitude to Mr. H. O. D computer science department, College for his encouraging support and guidance in carrying step forward the cast. I would standardised to express gratitude and indebtedness to Mr, for his valuable advice and guidance without which this project would non have seen the light of the day. I convey Mr , project guide , GSS for his insistence on good architectural planming technique which swear outed us to design and mystify a successful flummox of an Chatting Tool. Name CONTENTS 1.STUDY & ANALYSIS degree 1. 1 INTRODUCTION 1. 1. 1 PURPOSE OF THE cat 1. 1. 2 PROBLEM IN EXISTING SYSTEM 1. 1. 3 ancestor OF THESE PROBLEMS 1. 1. 4 SCOPE OF THE PROJECT 1. 1. 5 LIMITATIONS 1. 1. 6 computer hardwargon & SOFTWARE SPECIFICATIONS 1. 1. 7 ORGANISATION pro commove 2. PROJECT ANALYSIS 1. STUDY OF THE SYSTEM 2. gossip & product 3. PROCESS MODULES USED WITH JUSTIFICATION 3. DESIGN PHASE 1. DATAFLOW 2. UML platS 4. IMPLEMENTATION P HASE 5. raiseING 1. TYPES OF TESTING 1. COMPILING TEST 2. EXECUTION TEST 3. OUTPUT TEST 5. PROJECT CODING 6. OUTPUT SCREENS 7. CONCLUSION 8. BIBLOGRAPHYSTUDY PHASE INTRODUCTION EXISTING SYSTEM With the advent of the profits in the past decade, hunting for information in various formats has been redefined by the internet search locomotive rail path locomotives, intimately of them being ground on information retrieval (IR) indexing techniques. IR-based searching, which usu bothy throw ins formulation of queries with multiple wrangling PROPOSED SYSTEM This chocolate lotion is basic all(prenominal)y a recursive accommodate experienceer. You can search for blames based on their file separate, their contents, or both in aimed directory and as well as sub directories of the specified directory.Engine is a graphical version of the well- cognise GREP utility, with an additional feature of traversing subdirectories. You can specify which directory to start looking in, which file s to search through, and what conformation to look for in the files. The various fields expect lawful expressions, standardized Global unbroken Expression, Engine has not single the graphical interface, still as well a command- withdraw interface. This is effectual for quick searches through, say, a development tree. Engine requires the coffee tree 2 Platform, Standard Edition version 1. 4 or higher. SOLUTION OF THESE PROBLEMSRegular expressions figure into all kinds of school text-manipulation tasks. essaying and search-and-replace argon among the more than common construct role ofs, only first-string expressions can alike be use to test for certain conditions in a text file or info stream. You might use ceaseless expressions, for example, as the basis for a short political program that separates incoming chain mail from incoming spam. In this case, the program might use a official expression to determine whether the name of a kn suffer spammer appe ard i n the From line of the email. Email filtering programs, in fact, actually a great deal use steady expressions for exactly this type of operation. SCOPE OF THE PROJECTEngine is a graphical version of the well-known GREP utility, with an additional feature of traversing subdirectories. The chief(prenominal) aim of this project is to develop a java based recursive file finder. Engine is a graphical version of the well-known GREP utility, with an additional feature of traversing subdirectories LIMITATIONS Regular expressions t prohibit to be easier to indite than they be to necessitate. This is less of a problem if you are the only one who ever needs to maintain the program (or sed social function, or thrum script, or what have you), but if several people need to watch all over it, the phrase structure can turn into more of a hindrance than an aid.Ordinary macros (in particular, editable macros such as those generated by the major intelligence processors and editors) t hold on not to be as fast, as flexible, as portable, as concise, or as fault-tolerant as official expressions, but they have the advantage of being much more readable counterbalance people with no programing background whatsoever can usually make enough sentience of a macro script to vary it if the need arises. For some jobs, such readability provide outbalance all early(a) concerns.As with all amours in computing, its largely a question of fitting the tool to the job. HARDWARE & SOFTWARE SPECIFICATIONS Environment Java Runtime Environment version 1. 4 or better installed. Operating scheme Any O. S. compatable with JVM Hard disk10 GB ProcessorPIII or higher ORGANIZATION PROFILE EMINENT SOFTWARE SOLUTIONS EMINENT TECHNOLOGIES (ET) is an IT Solution Provider for a dynamic environment where caper and applied science strategies converge.Our progress focuses on bleak ways of business combining IT innovation and adoption while alike leveraging an organizations current IT assets . We work with large ball-shaped corporations and freshlyfangled generation engineering science companies to build brisk products or services and to implement prudent business and technology strategies in todays environment. EMINENTs range of expertise includes software product Development Services Engineering Services Systems Integration Customer Relationship deal outment Supply string Management Product Development Electronic CommerceConsulting IT Outsourcing We apply technology with innovation and responsibility to achieve deuce broad endives Effectively address the business issues our routineers face today Generate new opportunities that will help them stay ahead in the proximo This approach rests on A strategy where we Architect, Integrate and Manage technology services and solutions we call it AIM for success. A robust offshore development methodology and reduce demand on customer resources A focus on the use of reusable frameworks to provide greet and time benef itsWe combine the outdo people, processes and technology to achieve excellent results consistently. We cranny customers the advantages of Speed We understand the vastness of timing, of getting in that respect before the competition. A rich portfolio of reusable, modular frameworks helps jump start projects. Tried and well-tried methodology ensures that we follow a predictable, low-risk path to achieve results. Our track record is testimony to complex projects delivered at bottom and even before archive. Expertise Our teams combine cutting edge technology skills with rich domain expertise.Whats as minuteant we share a strong customer orientation that means we actually start by advertening to the customer. Were focused on coming up with solutions that dole out customer requirements today and anticipate future needs. A Full Service Portfolio We offer customers the advantage of being able to Architect, Integrate and Manage technology services. This means that they can rely on one, fully accountable source instead of filtering to shuffle disparate multi-vendor solutions. Services GSS is providing its services to Sain medicaments Pvt.Ltd, Grace drugs and pharmaceuticals Private Limited Alka Drugs and Pharmaceuticals Pvt Ltd to name just a some with out rich experience and expertise in Information Technology we are in the best position to provide software solutions to distinct business requirements. PROJECT ANALYSIS STUDY OF THE SYSTEM This application can be mainly divided into 2 modules- User Interface rouse Manipulation and filtering INPUT AND OUTPUT User has to insert the File Name or File Contents and he has to select the Drive or Directory in which searching has to be done.Application will search for the files co-ordinated with given criteria and shows the issue in the text area of the application. PROCESS MODEL USED WITH JUSTIFICTION The model used here is a SPIRAL MODEL. This Model demands a direct consideration of technical risk at all stages of the project and if properly applied it reduces risk before they be progress problematic, hence it baffles easier to handle a project when victimisation this kind of model where in the end user can evaluate the program at the end of individually stage and suggest modification if required.PROJECT DESIGN DATA FLOW DIAGRAM 0th Level initiative Level 2nd Level 2nd Level 3rd Level UML DIAGRAMS USE CASE DIAGRAM pic CLASS DIAGRAM pic ACTIVITY DIAGRAM pic SEQUENCE DIAGRAM pic IMPLEMENTATION PHASE MODULES 1. COMPONENT THIS IS THE bird-scarer END CONSOLE OF THE USER TO INTERACT WITH SEARCH ANALYZER. 2. TOOLBAR COORDINATIOR THIS MODULE HAS THE EMBEDED TOOLS WHICH ARE TO IMPLEMENT SEARCH. 3. MAP finder THIS MODULE IS MAPS THE SEARCH CORRESPONDING TO THE USERS QUERY. 4. DYNAMIC STATUS FINDERTHIS IS THE DYNAMIC MODULE WHICH GIVES THE STATUS OF THE SEARCH . 5. GREP author GREP GENERATOR IS THE MAJOR MODULE ON WHICH THE SEARCH IS DONE BASED ON REGULAR EXPRESSIONS . OUTPUT SCREENS Eng ine view pic Browse pic Search pic Help pic Error pic PROJECT CODING CODE interpretation Regular expressions simplify soma- tinting code Discover the elegance of stiff expressions in text- bear on scenarios that involve pattern have-to doe withing Text processing practically involves lucifering text against a pattern.Although Javas voice and assorted string setes offer low-level pattern- disciplineing support, that support commonly leads to complex code. To help you write simpler pattern-matching code, Java provides regular expressions with java. util. regex package. Text processing frequently requires code to match text against patterns. That capability makes possible text searches, email header validation, custom text creation from generic text (e. g. , Dear Mr. Chakradhar instead of Dear Customer), and so on. Java supports pattern matching via its use and assorted string classes.Because that low-level support commonly leads to complex pattern-matching code, Java beside s offers regular expressions to help you write simpler code. After introducing regular expression terminology, the java. util. regex packages classes, and a program that demonstrates regular expression constructs, I explore many of the regular expression constructs that the Pattern class supports. I also examine the methods comprising Pattern and other java. util. regex classes. A practical application of regular expressions concludes my discussion.Regular expressions long history begins in the theoretical computer science fields of automata theory and formal language theory. That history continues to Unix and other turn tail systems, where regular expressions are often used in Unix and Unix-like utilities examples include awk (a programming language that enables sophisticated text analysis and manipulation-named after its creators, Aho, Weinberger, and Kernighan), emacs (a developers editor), and grep (a program that matches regular expressions in one or more text files and stand s for global regular expression print).Regular expressions trace back to the work of an American mathematician by the name of Stephen Kleene (one of the intimately effectant figures in the development of theoretical computer science) who developed regular expressions as a notation for describing what he called the algebra of regular sets. His work eventually found its way into some early efforts with computational search algorithms, and from there to some of the earliest text-manipulation tools on the Unix platform (including ed and grep). In the context of computer searches, the * is formally known as a Kleene star. A regular expression, also known as a regex or regexp, is a string whose pattern (template) describes a set of strings. The pattern determines what strings belong to the set, and consists of literal constituents and meta characters, characters that have peculiar(a) substance instead of a literal meaning. The process of searching text to identify matchesstrings th at match a regexs patternis pattern matching. Javas java. util. regex package supports pattern matching via its Pattern, matcher, and PatternSyntaxException classes 1. Pattern objects, also known as patterns, are compiled regexes 2.Matcher objects, or matchers, are engines that interpret patterns to locate matches in character sequences, objects whose classes implement the java. lang. CharSequence interface and serve as text sources 3. PatternSyntaxException objects describe illegal regex patterns inscribe for mainwindow package jog. engine import java. awt. * import java. awt. event. * import java. io. * import java. net. URL import java. util. prefs. * import java. util. regex. * import javax. swing. * import javax. swing. filechooser. FileFilter import jog. engine. * prevalent class MainWindow extends JFrame implements ActionListener, FileSearchListener rotected Preferences preferences defend JTextField lookInField cling to JTextField filePatternField saved JTextField sea rchForField defend JTextField excludeField defend JCheckBox includeSubCheckBox protected JList resultList protected RunSearch runner protected JButton browseButton protected JButton helpButton protected JButton startButton protected JButton stopButton protected JButton closeButton protected JLabel status protected JPanel cardPanel protected CardLayout cardLayout private boolean stopFlag humans MainWindow() super( slew. get string along(AppTitle)) addWindowListener(new WindowAdapter() man def trim windowClosing(WindowEvent event) handleClose() ) preferences = Preferences. userRoot(). node(com/bluemarsh/jrgrep) Container pane = getContentPane() GridBagLayout gb = new GridBagLayout() pane. setLayout(gb) GridBagConstraints gc = new GridBagConstraints() gc. insets = new Insets(3, 3, 3, 3) JLabel label = new JLabel(Bundle. get drawstring(lookInLabel)) gc. vertebral column = GridBagConstraints. EAST gb. setConstraints(label, gc) pane. add(label) puff s = preferences. get(lookIn, ) lookInField = new JTextField(s, 20) gc. back = GridBagConstraints. WEST gc. fill = GridBagConstraints. even gc. weightx = 1. 0 gb. setConstraints(lookInField, gc) pane. add(lookInField) browseButton = new JButton(Bundle. get run(browseLabel)) browseButton. addActionListener(this) gc. mainstay = GridBagConstraints. CENTER gc. gridwidth = GridBagConstraints. REMAINDER gc. fill = GridBagConstraints. NONE gc. weightx = 0. 0 gb. setConstraints(browseButton, gc) pane. add(browseButton) label = new JLabel(Bundle. getString(filePatternLabel)) gc. anchor = GridBagConstraints. EAST gc. gridwidth = 1 gb. setConstraints(label, gc) pane. add(label) s = preferences. get(filter, ) ilePatternField = new JTextField(s, 20) gc. anchor = GridBagConstraints. WEST gc. fill = GridBagConstraints. HORIZONTAL gc. gridwidth = GridBagConstraints. coitus gc. weightx = 1. 0 gb. setConstraints(filePatternField, gc) pane. add(filePatternField) role glue = Box. forceGlue() gc. anchor = GridBagConstraints. CE NTER gc. fill = GridBagConstraints. NONE gc. gridwidth = GridBagConstraints. REMAINDER gc. weightx = 0. 0 gb. setConstraints(glue, gc) pane. add(glue) label = new JLabel(Bundle. getString(searchForLabel)) gc. anchor = GridBagConstraints. EAST gc. fill = GridBagConstraints.NONE gc. gridwidth = 1 gb. setConstraints(label, gc) pane. add(label) s = preferences. get(searchFor, ) searchForField = new JTextField(s, 20) gc. anchor = GridBagConstraints. WEST gc. fill = GridBagConstraints. HORIZONTAL gc. gridwidth = GridBagConstraints. RELATIVE gc. weightx = 1. 0 gb. setConstraints(searchForField, gc) pane. add(searchForField) helpButton = new JButton(Bundle. getString(helpLabel)) helpButton. addActionListener(this) gc. anchor = GridBagConstraints. CENTER gc. fill = GridBagConstraints. NONE gc. gridwidth = GridBagConstraints. REMAINDER gc. weightx = 0. 0 gb. etConstraints(helpButton, gc) pane. add(helpButton) label = new JLabel(Bundle. getString(excludeLabel)) gc. anchor = GridBagConstraints. EAST gc. gridwidth = 1 gb. setConstraints(label, gc) pane. add(label) s = preferences. get(exclude, ) excludeField = new JTextField(s, 20) gc. anchor = GridBagConstraints. WEST gc. fill = GridBagConstraints. HORIZONTAL gc. gridwidth = GridBagConstraints. RELATIVE gc. weightx = 1. 0 gb. setConstraints(excludeField, gc) pane. add(excludeField) glue = Box. createGlue() gc. anchor = GridBagConstraints. CENTER gc. fill = GridBagConstraints. NONE gc. ridwidth = GridBagConstraints. REMAINDER gc. weightx = 0. 0 gb. setConstraints(glue, gc) pane. add(glue) includeSubCheckBox = new JCheckBox( Bundle. getString(includeSubDirLabel), unbowed) includeSubCheckBox. setSelected(preferences. getBoolean( recurse, true)) gc. anchor = GridBagConstraints. WEST gb. setConstraints(includeSubCheckBox, gc) pane. add(includeSubCheckBox) startButton = new JButton( Bundle. getString(startSearchLabel)) startButton. addActionListener(this) gc. gridwidth = 1 gb. setConstraints(startButton, gc) pane. add(startBut ton) status=new JLabel() Color c=new Color(240,100,100) tatus. setForeground(c) gc. gridwidth = 1 gb. setConstraints(status, gc) pane. add(status) stopButton = new JButton(Bundle. getString(stopLabel)) stopButton. setEnabled( chimerical) stopButton. addActionListener(this) gc. anchor = GridBagConstraints. CENTER gc. gridwidth = GridBagConstraints. RELATIVE gb. setConstraints(stopButton, gc) pane. add(stopButton) closeButton = new JButton(Bundle. getString(closeLabel)) closeButton. addActionListener(this) gc. gridwidth = GridBagConstraints. REMAINDER gb. setConstraints(closeButton, gc) pane. add(closeButton) resultList = new JList(new ResultsListModel())JScrollPane scroller = new JScrollPane(resultList) cardPanel = new JPanel(new CardLayout()) cardLayout = (CardLayout) cardPanel. getLayout() cardPanel. add(scroller, heel) gc. gridwidth = GridBagConstraints. REMAINDER gc. gridheight = GridBagConstraints. REMAINDER gc. fill = GridBagConstraints. BOTH gc. weightx = 1. 0 gc. weighty = 1 . 0 gb. setConstraints(cardPanel, gc) pane. add(cardPanel) int width = preferences. getInt(windowWidth, 0) int height = preferences. getInt(windowHeight, 0) if (width == 0 && height == 0) pack() else setSize(width, height) int top = preferences. getInt(windowTop, 100) nt left = preferences. getInt(windowLeft, 100) setLocation(left, top) stopFlag= fictional human beings vacuum actionPerformed(ActionEvent event) JButton button = (JButton) event. getSource() //System. out. println(action +button) if (button == closeButton) handleClose() else if (button == browseButton) handleBrowse() else if (button == startButton) status. setText(Search Started) //System. out. println(Search started) startSearch() else if (button == helpButton) displayHelp() else if (button == stopButton) //System. out. println(Search stopped) stopButton. setEnabled(false) runner. stop() stopFlag=true /int count=((ListModel)resultList. getModel()). getSize() //status. setText(Search Stopped +count+ Fi les Found) protected stave off displayHelp() if (cardPanel. getComponentCount() 2) URL helpUrl = Bundle. getResource(helpFile) try JEditorPane editor = new JEditorPane(helpUrl) editor. setEditable(false) JScrollPane scroller = new JScrollPane(editor) cardPanel. add(scroller, help) snap fastener (IOException ioe) searchFailed(ioe) devote cardLayout. show(cardPanel, help) national forefend fileFound(FileFoundEvent event) ResultsListModel model = (ResultsListModel) resultList. etModel() model. addElement(event. getFile()) protected void handleBrowse() String dirStr = lookInField. getText() JFileChooser fc if (dirStr. equals()) String lastdir = preferences. get(lastdir, shadowy) if (lastdir == goose egg lastdir. length() == 0) lastdir = System. getProperty(user. dir) fc = new JFileChooser(lastdir) else fc = new JFileChooser(dirStr) fc. setFileSelectionMode(JFileChooser. DIRECTORIES_ONLY) if (fc. showOpenDialog(this) = JFileChooser. CANCEL_OPTION) File dir = fc. getSelectedFile() String path = dir. getPath() lookInField. setText(path) references. put(lastdir, path) protected void handleClose() preferences. putInt(windowTop, getY()) preferences. putInt(windowLeft, getX()) preferences. putInt(windowWidth, getWidth()) preferences. putInt(windowHeight, getHeight()) preferences. put(lookIn, lookInField. getText()) preferences. put(filter, filePatternField. getText()) preferences. put(searchFor, searchForField. getText()) preferences. put(exclude, excludeField. getText()) preferences. putBoolean(recurse, includeSubCheckBox. isSelected()) System. exit(0) public void searchComplete() stopButton. etEnabled(false) //status. setText(Search established) int count=((ListModel)resultList. getModel()). getSize() if(count==0) status. setText(Search Completed No Files Found) if(stopFlag) status. setText(Search Stopped +count + Files Found) stopFlag=false else status. setText(Search Completed +count + Files Found) public void searchFailed(Throw able t) Object messages = Bundle. getString(exceptionOccurred),t. getMessage() JOptionPane. showMessageDialog(this, messages, Bundle. getString(errorTitle), JOptionPane. ERROR_MESSAGE) protected void startSearch() cardLayout. how(cardPanel, list) ResultsListModel model = (ResultsListModel) resultList. getModel() model. clear() String dirStr = lookInField. getText() if (dirStr == null dirStr. length() == 0) dirStr = . File dir = new File(dirStr) if ( dir. exists()) JOptionPane. showMessageDialog(this, Bundle. getString(pathDoesNotExist), Bundle. getString(errorTitle), JOptionPane. ERROR_MESSAGE) return String target = searchForField. getText() String filter = filePatternField. getText() String exclude = excludeField. getText() try Pattern. compile(target) Pattern. compile(filter) Pattern. ompile(exclude) catch (PatternSyntaxException pse) Object messages = Bundle. getString(invalidRegexPattern), pse. getMessage() JOptionPane. showMessageDialog(this, messages, Bundle. getS tring(errorTitle),JOptionPane. ERROR_MESSAGE) return if (runner == null) runner = new RunSearch(this) runner. search(dir, target, filter, includeSubCheckBox. isSelected(), exclude) Thread th = new Thread(runner) th. start() stopButton. setEnabled(true) Code for roll package jog. engine import java. net. URL import java. util. MissingResourceException import java. til. ResourceBundle public class Bundle private static ResourceBundle resourceBundle static resourceBundle = ResourceBundle. getBundle(Bundle. class. getName()) public static ResourceBundle getBundle() return resourceBundle public static URL getResource(String key) String name = getString(key) return name == null ? null Bundle. class. getResource(name) public static String getString(String key) try return resourceBundle. getString(key) catch (MissingResourceException mre) return null Code for runsearch package jog. engine import java. io. File import jog. engine. * mport java. lang. * class RunSearch im plements Runnable protected File dir protected String lookFor protected String filter protected boolean subDirs protected String exclude protected FileSearchListener attendee protected searcher beetle quester public RunSearch(FileSearchListener listener) this. listener = listener public void run() if (searcher == null) searcher = new Searcher() if (listener = null) searcher. addSearchListener(listener) searcher. search(dir, lookFor, filter, subDirs, exclude) public void search(File dir, String lookFor, String filter, boolean subDirs, String exclude) this. dir = dir this. lookFor = lookFor this. filter = filter this. subDirs = subDirs this. exclude = exclude public void stop() //System. out. println(Searcher is one+ isAlive()) System. out. println(Searcher) if (searcher = null) searcher. stopSearching() searcher=null System. out. println(Searcher one) //System. out. println(Searcher is + isAlive()) //System. out. println(Searcher one) Code for searcher package jog . engine import java. io. * import java. nio. * import java. nio. channels. * import java. nio. charset. * import java. util. * import java. til. regex. * import javax. swing. event. EventListenerList import jog. engine. * class Searcher protected static Pattern linePattern protected static Charset charset protected static CharsetDecoder decoder protected EventListenerList searchListeners protected volatile boolean stopSearch protected Pattern targetPattern protected Matcher targetMatcher protected Pattern filterPattern protected Matcher filterMatcher protected Pattern excludePattern protected Matcher excludeMatcher static try linePattern = Pattern. compile(. * ? ) catch (PatternSyntaxException pse) System. out. rintln(Ye flipping gods ) charset = Charset. forName(ISO-8859-1) decoder = charset. newDecoder() public Searcher() searchListeners = new EventListenerList() public void addSearchListener(FileSearchListener listener) searchListeners. add(FileSearchListener. class, l istener) protected void fireDone() if (searchListeners == null) return Object listeners = searchListeners. getListenerList() for (int i = listeners. length 2 i = 0 i -= 2) if (listenersi == FileSearchListener. class) FileSearchListener fsl = (FileSearchListener) listenersi + 1 fsl. earchComplete() protected void fireError(Throwable t) if (searchListeners == null) return Object listeners = searchListeners. getListenerList() for (int i = listeners. length 2 i = 0 i -= 2) if (listenersi == FileSearchListener. class) FileSearchListener fsl = (FileSearchListener) listenersi + 1 fsl. searchFailed(t) protected void fireFound(String match) if (searchListeners == null) return FileFoundEvent event = new FileFoundEvent(this, match) Object listeners = searchListeners. getListenerList() for (int i = listeners. ength 2 i = 0 i -= 2) if (listenersi == FileSearchListener. class) FileSearchListener fsl = (FileSearchListener) listenersi + 1 fsl. fileFound(event) event = nul l public void removeSearchListener(FileSearchListener listener) searchListeners. remove(FileSearchListener. class, listener) public void search(File startIn, String target, String filter, boolean recurse, String exclude) stopSearch = false try targetPattern = Pattern. compile(target) filterPattern = Pattern. compile(filter) if (exclude = null && exclude. length() 0) excludePattern = Pattern. ompile(exclude) searchLow(startIn, recurse) catch (IOException ioe) fireError(ioe) catch (PatternSyntaxException pse) fireError(pse) targetPattern = null targetMatcher = null filterPattern = null filterMatcher = null excludePattern = null excludeMatcher = null fireDone() protected void searchLow(File startIn, boolean recurse) throws IOException String files = startIn. list() if (files == null) return for (int ii = 0 ii files. length ii++) if (stopSearch) break File file = new File(startIn, filesii) if (file. isFile() && file. canRead()) String filename = file. etCanonicalP ath() if (filterMatcher == null) filterMatcher = filterPattern. matcher(filename) else filterMatcher. reset(filename) if ( filterMatcher. find()) continue FileInputStream fis = new FileInputStream(file) FileChannel fc = fis. getChannel() MappedByteBuffer bb = fc. map(FileChannel. MapMode. READ_ONLY, 0, fc. size()) CharBuffer cb = decoder. decode(bb) boolean matchFound = false if ((targetPattern. flags() & Pattern. DOTALL) = 0) if (targetMatcher == null) targetMatcher = targetPattern. matcher(cb) else argetMatcher. reset(cb) if (targetMatcher. find()) matchFound = true else Matcher lm = linePattern. matcher(cb) while (lm. find()) CharSequence cs = lm. group() if (targetMatcher == null) targetMatcher = targetPattern. matcher(cs) else targetMatcher. reset(cs) if (targetMatcher. find()) matchFound = true if (lm. end() == cb. limit()) break if (matchFound) fireFound(filename) else if (recurse && file. isDirectory()) String dirname = file. getName() if (excl udePattern = null) if (excludeMatcher == null) excludeMatcher = excludePattern. atcher(dirname) else excludeMatcher. reset(dirname) if ( excludeMatcher. find()) searchLow(file, recurse) else searchLow(file, recurse) public void stopSearching() stopSearch = true Code for filesearch listener package jog. engine import java. util. EventListener import jog. engine. FileFoundEvent interface FileSearchListener extends EventListener public void fileFound(FileFoundEvent event) public void searchComplete() public void searchFailed(Throwable t) Code for tty package jog. engine import java. io. * import java. util. regex. * mport jog. engine. * public class tty implements FileSearchListener protected static int argIndex protected static String excludeStr = protected static String nameStr = protected static void displayHelp() String str = Bundle. getString(ttyHelp1) int i = 1 while (str = null) System. out. println(str) i++ str = Bundle. getString(ttyHelp + i) public void fileFound(FileFoundEvent event) System. out. println(event. getFile()) protected static boolean processArgs(String args) while (argIndex args. length) String arg = argsargIndex if (arg. equals(-exclude)) rgIndex++ excludeStr = argsargIndex else if (arg. equals(-h) arg. equals(-help) arg. equals(help)) displayHelp() return false else if (arg. equals(-name)) argIndex++ nameStr = argsargIndex else break argIndex++ return true public void searchComplete() public void searchFailed(Throwable t) System. err. println(Bundle. getString(exceptionOccurred)) System. err. println(t. getMessage()) public static void main(String args) try if ( processArgs(args)) return catch (ArrayIndexOutOfBoundsException aioobe) System. err. println(Bundle. etString(ttyMissingArguments)) return if (argIndex == args. length) System. err. println(Bundle. getString(ttyMissingRequired)) return String target = argsargIndex argIndex++ String dirStr = null if (argIndex == args. length) dirStr = . else dirStr = argsargIndex File dir = new File(dirStr) if ( dir. exists()) System. err. println(Bundle. getString(pathDoesNotExist)) return try Pattern. compile(target) Pattern. compile(nameStr) catch (PatternSyntaxException pse) System. err. println(Bundle. getString(invalidRegexPattern)) System. rr. println(pse. getMessage()) return Searcher searcher = new Searcher() tty instance = new tty() searcher. addSearchListener(instance) searcher. search(dir, target, nameStr, true, excludeStr) searcher. removeSearchListener(instance) Code for filefoundevent package jog. engine import java. util. EventObject class FileFoundEvent extends EventObject protected String file public FileFoundEvent(Object source, String file) super(source) this. file = file public String getFile() return file Code for result list model package jog. engine import java. util. Vector import javax. wing. AbstractListModel import jog. engine. * class ResultsListModel extends AbstractListM odel protected Vector listData public ResultsListModel() listData = new Vector() public void addElement(Object o) listData. add(o) fireIntervalAdded(this, listData. size(), listData. size()) public void clear() int size = listData. size() listData. clear() fireIntervalRemoved(this, 0, size) public Object getElementAt(int i) try return listData. elementAt(i) catch (ArrayIndexOutOfBoundsException e) return null public int getSize() return listData. size() Code for main package jog. ngine import jog. engine. * public class Main public static void main(String args) new MainWindow(). show() // new jog. searchdesk. MainWindow. show() For a tool with full regex support, metacharacters like * and ? (or wildcard operators, as they are some clock called) are only the tip of the iceberg. Using a good regex engine and a well-crafted regular expression, one can easily search through a text file (or a coulomb text files) searching for oral communication that have the suffi x . html (but only if the word begins with a detonator letter and occurs at the solution of the line), replace the . tml suffix with a . sgml suffix, and consequently change all the lower case characters to upper case. With the right tools, this series of regular expressions would do just that s/(A_Z1)(a-z+). sgml/12. html/g tr/a-z/A-Z/ As you might guess from this example, concision is everything when it comes to crafting regular expressions, and while this syntax wont win any beauty prizes, it follows a logical and fairly standardized format which you can shape to rea+*d and write easily with just a little bit of practice. In a regular expression, everything is a generalized pattern.If I type the word serendipitous into my editor, Ive created one instance of the word serendipitous. If, however, I indicate to my tool (or compiler, or editor, or what have you) that Im now typing a regular expression, I am in effect creating a template that matches all instances of the character s s, e, r, e, n, d, i, p, i, t, o, u, and s all in a row. The standard way to find serendipitous (the word) in a file is to use serendipitous (the regular expression) with a tool like egrep (or extended grep) $ egrep serendipitous foobar hitsThis line, as you might guess, asks egrep to find instances of the pattern serendipitous in the file foobar and write the results to a file called hits. In the preceding examples, we have been using regular expressions that adhere to the first rule of regular expressions namely, that all alphanumeric characters match themselves. There are other characters, however, that match in a more generalized fashion. These are usually referred to as the meta characters. Some meta characters match wholeness characters. This includes the following tokens . Matches any one character Matches any character listed mingled with the brackets Matches any character except those listed between the brackets Suppose we have a chassis of filenames listed out in a f ile called Important. files. We fatality to grep out those filenames which follow the pattern blurfle1, blurfle2, blurfle3, and so on, but exclude files of the form 1blurfle, 2blurfle, 3blurfle The following regex would do the trick $ egrep blurfle. Important. files blurfles The pregnant thing to realize here is that this line will not match only when the string blurfle. (that is, blurfle followed by a item). In a regular expression, the dot is a reserved symbol (well get to matching periods a little further on). This is fine if we arent particular about the character we match (whether its a 1, a 2, or even a letter, a space, or an underscore). Narrowing the field of choices for a single character match, however, requires that we use a character class. Character classes match any character listed within that class and are separated off using square brackets.So, for example, if we compulsioned to match on blurfle but only when it is followed immediately by a digit (including blurfle1 but not blurflez) we would use something like this $ egrep blurfle0123456789 Important. files blurfles The syntax here is exactly as it seems notice blurfle followed by a nothing, a one, a two, a three, a four, a five, a six, a seven, an eight, or a nine. Such classes are usually abbreviated using the range operator (-) $ egrep blurfle0-9 Important. files blurfles The following regex would find blurfle followed by any alphanumeric character (upper or lower case). egrep blurfle0-9A-Za-z Important. files blurfles (Notice that we didnt write blurfle0-9 A-Z a-z for that last one. The spaces might make it easier to read, but wed be matching on anything between zero and nine, anything between a and z, anything between A and Z, or a space. ) A carat at the ascendant of the character class negates that class. In other words, if you wanted to find all instances of blurfle except those which end in a figure of speech, youd use the following $ egrep blurfle0-9 Important. files bl urfles Many regex implementations have macros for various character classes.In Perl, for example, d matches any build (0-9) and w matches any word character (a-zA-Z0-9_). Grep uses a moderately different notation for the same thing material body for digits and alnum for alphanumeric characters. The man page (or other documentation) for the particular tool should list all the regex macros introductionible for that tool. Quantifiers The regular expression syntax also provides metacharacters which specify the spot of times a particular character should match. ?Matches any character zero or one times *Matches the preceding element zero or more times +Matches the preceding element one or more times numMatches the preceding element num times min, maxMatches the preceding element at least min times, but not more than max times These metacharacters allow you to match on a single-character pattern, but then continue to match on it until the pattern changes. In the last example, we were trying to search for patterns that contain blurfle followed by a sum between zero and nine. The regex we came up with would match on blurfle1, blurfle2, blurfle3, etc. If, however, you had a programmer who mistakenly judgment that blurfle was supposed to be spelled blurffle, our regex wouldnt be able to catch it.We could fix it, though, with a quantifier. $ egrep blurf+le0-9 Important. files blurfles Here we have Find b, l, u, r (in a row) followed by one or more instances of an f followed by l and e and then any single digit character between zero and nine. Theres always more than one way to do it with regular expressions, and in fact, if we use single-character metacharacters and quantifiers in conjunction with one another, we can search for al some all the variant spellings of blurfle (bllurfle, bllurrfle, bbluuuuurrrfffllle, and so on).One way, for example, might employ the ubiquitous (and exceedingly powerful) . * combination $ egrep b. *e Important. files blurfles If we wo rk this out, we come out with something like find a b followed by any character any number of times (including zero times) followed by an e. Its tempting to use . * with abandon. However, bear in mind that the preceding example would match on words like blue and baritone as well as blurfle. Suppose the filenames in blurfle are numbered up to 12324, but we only care about the first 999 $ egrep blurfle0-93 Important. files bluflesThis regex tells egrep to match any number between zero and nine exactly three times in a row. Similarly, blurfle0-93,5 matches any number between zero and nine at lest three times but not more than five times in a row. Anchors Often, you need to specify the position at which a particular pattern occurs. This is often referred to as anchoring the pattern Matches at the start of the line $Matches at the end of the line Matches at the end of a word Matches at the beginning or the end of a word BMatches any charater not at the beginning or end of a word and $ are some of the intimately useful metacharacters in the regex arsenalparticularly when you need to run a search-and-replace on a list of strings. Suppose, for example, that we want to take the blurfle files listed in Important. files, list them out separately, run a program called fragellate on each one, and then append each successive output to a file called fraggled_files. We could write a full-blown graduated table script (or Perl script) that would do this, but often, the job is faster and easier if we build a very simple shell script with a series of regular expressions.Wed begin by greping the files we want to operate on and committal to writing the output to a file. $ egrep blurfle0-9 Important. file script. sh This would give us a list of files in script. sh that looked something like this blurfle1 blurfle2 blurfle3 blurfle4 . . . immediately we use sed (or the /%s operator in vi, or the query-replace-regexp command in emacs) to put fragellate in motion of each filena me and fraggled_files after each filename. This requires two separate search-and-replace operations (though not necessarily, as Ill apologise when we get to backreferences).With sed, you have the ability to put both substitution lines into a file, and then use that file to iterate through another making each substitution in turn. In other words, we create a file called fraggle. sed which contains the following lines s//fraggelate / s/$/ fraggled_files/ Then run the following sed routine on script. sh like so $ sed -f fraggle. sed script. sh script2. sh Our script would then look like this fraggelate blurfle1 fraggled_files fraggelate blurfle2 fraggled_files fraggelate blurfle3 fraggled_files raggelate blurfle4 fraggled_files . . Chmod it, run it, and youre done. Of course, this is a somewhat picayune example (Why wouldnt you just run fragglate blurfle* fraggled_files from the command line? ). Still, one can easily consider instances where the criteria for the file name list is to o complicated to express using filename* on the command line. In fact, you can probably see from this sed-routine example that we have the makings of an automatic shell-script generator or file filter. You whitethorn also have noticed something odd about that caret in our sed routine.Why doesnt it mean except as in our previous example? The dish has to do with the sometimes radical difference between what an operator means inside the range operator and what it means outside it. The rules change from tool to tool, but generally speaking, you should use metacharacters inside range operators with caution. Some tools dont allow them at all, and others change the meaning. To pick but one example, most tools would interpret A-Za-z. as Any character between A and Z, a and z or a period. Most tools provide some way to anchor a match on a word boundary.In some versions of grep, for example, you are allowed to write $ grep fle Important. files blurfles This says Find the characters f, l, e , but only when they come at the end of a word. tells the regex engine to match any word boundary (whether its at the beginning or the end) and B tells it to match any position that isnt a word boundary. This again can motley considerably from tool to tool. Some tools dont support word boundaries at all, and others support them using a slightly different syntax.The tools that do support word boundaries generally consider words to be bounded by spaces or punctuation, and consider numerals to be legitimate parts of words, but there are some variations on these rules that can effect the accuracy of your matches. The man page or other documentation should resolve the matter. elude Characters By now, youre probably wondering how you go about searching for one of the special characters (asterisks, periods, slashes, and so on). The answer lies in the use of the escape characterfor most tools, the backslash ().To reverse the meaning of a special character (in other words, to treat it as a normal character instead of as a metacharacter), we exactly put a backslash before that character. So, we know that a regex like . * finds any character any number of times. But suppose were searching for ellipses of various lengths and we just want to find periods any number of times. Because the period is normally a special character, wed need to escape it with a backslash $ grep . * Important. Files ellipses. files Unfortunately, this contribute to the legendary ugliness of regular expressions more than any other element of the syntax.Add a few escape characters, and a simple sed routine designed to replace a couple of URLs quickly degenerates into confusion sed s/http//etext. lib. virginia. edu//http//www. etext. virginia. edu/g To make matters worse, the list of what needs to be escaped differs from tool to tool. Some tools, for example, consider the + quantifier to have its normal meaning (as a ordinary plus sign) until it is escaped. If youre having trouble with a regex ( a sed routine that wont parse or a grep pattern that wont match even though youre certain the pattern exists), try playing around with the escapes.Or better yet, read the man page. Alternation Alternation refers to the use of the symbol to indicate logical OR. In a previous example, we used blurf+le to catch those instances of blurfle that were misspelled with two fs. Using alternation, we could have written $ egrep blurfleblurffle Important. files blurfles This means simply Find either blurfle OR blurffle. The power of this becomes more evident when we use parentheses to limit the scope of the alternative matches.Consider the following regex, which accounts for both the American and British spellings of the word gray $ egrep gr(ae)y Important. files hazy. shades Or perhaps a mail-filtering program that uses the following regex to single out past correspondence between you and the boss /(ToFrom) (SeamanRamsay)/ This says, Find a To or a From line followed by a space and then eithe r the word Seaman or the word Ramsay This can make your regexs extremely flexible, but be careful Parentheses are also meta characters which figure prominently in the use of . . . Back referencesPerhaps the most powerful element of the regular expression syntax, back references allows you to load the results of a matched pattern into a modify and then reuse it later in the expression. In a previous example, we used two separate regular expressions to put something before and after a filename in a list of files. I mentioned at that point that it wasnt entirely necessary that we use two lines. This is because back references allow us to get it down to one line. Heres how s/(blurfle0-9+)/fraggelate 1 fraggled_files/ The key elements in this example are the parentheses and the 1.Earlier we noted that parentheses can be used to limit the scope of a match. They can also be used to save a particular pattern into a temporary buffer. In this example, everything in the search half of the sed routine (the blurfle part) is saved into a buffer. In the replace half we recall the contents of that buffer back into the string by referring to its buffer number. In this case, buffer 1. So, this sed routine will do precisely what the rather one did find all the instances of blurfle followed by a number between zero and nine and replace it with fragellate blurflesome number fraggled files.Backreferences allow for something that very few ordinary search engines can take namely, strings of information that change slightly from instance to instance. Page numbering schemes provide a undefiled example of this. Suppose we had a document that numbered each page with the notation . The number and the chapter name change from page to page, but the rest of the string stays the same. We can easily write a regular expression that matches on this string, but what if we wanted to match on it and then replace everything but the number and the chapter name? //Page 1, Chapter 2/ Buffer number one (1) holds the first matched sequence, (0-9+) buffer number two (2) holds the second, (A-Za-z+). Tools vary in the number of backreference they can hold. The more common tools (like sed and grep) hold nine, but Python can hold up to ninety-nine. Perl is limited only by the amount of physical memory (which, for all practical projects, means you can have as many as you want). Perl also lets you assign the buffer number to an ordinary scalar variable ($1, $2, etc. ) so you can use it later on in the code block. a.OBJECT ORIENTED PROGRAMMING AND JAVA Object-oriented Programming was developed because of limitations found in earlier approaches of programming. To appreciate what OOP does, we need to understand what these limitations are and how they arose from traditional programming. PROCEDURAL LANGUAGES Pascal, C, Basic, FORTRAN, and similar languages are adjectival languages. That is, each statement in the language tells the computer to do something Get some input, add these numbe rs, divide by 6, display the output. A program in a procedural language is a list of instructions.For very small programs no other organizing principle (often called a paradigm) is needed. The programmer creates the list of instructions, and the computer carries them out. Division into Functions When programs become larger, a single list of instructions becomes unwieldy. Few programmers can comprehend a program of more than a few hundred statements unless it is broken down into smaller units. For this reason the function was adopted as a way to make programs more comprehensible to their human creators. (The term functions is used in C++ and C.In other languages the same concept may be referred to as a subroutine, a subprogram, or a procedure. ) A program is divided into functions, and (ideally, at least) each function has a clearly defined purpose and a clearly defined interface to the other functions in the program. The idea of breaking a program into functions can be further exten ded by grouping a number of functions together into a larger entity called a module, but the principle is similar grouping a number of components that carry out specific tasks.Dividing a program into functions and modules is one of the cornerstones of incorporated programming, the somewhat loosely defined discipline that has influenced programming organization for more than a decade. Problems with Structured Programming As programs grow ever larger and more complex, even the structured programming approach begins to show signs of strain. You may have heard about, or been have-to doe with in, horror stories of program development. The project is too complex, the schedule slips, more programmers are added, complexity increases, costs skyrocket, the schedule slips further, and disaster ensues.Analyzing the reasons for these failures reveals that there are weaknesses in the procedural paradigm itself. No matter how well the structured programming approach is implemented, large program s become excessively complex. What are the reasons for this failure of procedural languages? One of the most crucial is the role played by data. Data Undervalued In a procedural language, the speech pattern is on doing thingsread the keyboard, invert the vector, check for errors, and so on. The subdivision of a program into functions continues this emphasis. Functions do things just as single program statements do.What they do may be more complex or abstract, but the emphasis is still on the action. What happens to the data in this paradigm? Data is, after all, the reason for a programs existence. The important part of an inventory program isnt a function that displays the data, or a function that checks for correct input its the inventory data itself. Yet data is given second-class status in the organization of procedural languages. For example, in an inventory program, the data that makes up the inventory is probably read from a disk file into memory, where it is treated as a glo bal variable.By global we mean that the variables that constitute the data are stated outside of any function, so they are glide pathible to all functions. These functions perform various operations on the data. They read it, analyze it, update it, rearrange it, display it, write it back to the disk, and so on. We should note that most languages, such as Pascal and C, also support local variables, which are hidden within a single function. But local variables are not useful for important data that must be accessed by many different functions. Now suppose a new programmer is hired to write a function to analyze this nventory data in a certain way. Unfamiliar with the subtleties of the program, the programmer creates a function that accidentally corrupts the. This is easy to do, because every function has complete access to the data. Its like leaving your ain papers in the lobby of your apartment building Anyone can change or destroy them. In the same way, global data can be corrupt ed by functions that have no business changing it. Another problem is that, since many functions access the same data, the way the data is stored becomes critical.The arrangement of the data cant be changed without modifying all the functions that access it. If you add new data items, for example, youll need to modify all the functions that access the data so that they can also access these new items. It will be hard to find all such functions, and even harder to modify all of them correctly. Its similar to what happens when your local supermarket moves the bread from aisle 4 to aisle 12. Everyone who patronizes the supermarket must figure out where the bread has gone, and adjust their shopping habits accordingly.What is needed is a way to restrict access to the data, to hide it from all but a few critical functions. This will protect the data, simplify maintenance, and offer other benefits as well. Relationship to the Real World Procedural programs are often difficult to design. Th e problem is that their chief componentsfunctions and data structuresdont model the real world very well. For example, suppose you are writing a program to create the elements of a graphics user interface menus, windows, and so on. dissipated now, what functions will you need? What data structures?The answers are not obvious, to say the least. It would be better if windows and menus corresponded more nearly to actual program elements. New Data Types There are other problems with traditional languages. One is the bother of creating new data types. Computer languages typically have several built-in data types integers, floating-point numbers, characters, and so on. What if you want to invent your own data type? Perhaps you want to work with complex numbers, or two dimensional coordinates, or datesquantities the built-in data types dont handle easily.Being able to create your own types is called extensibility you can extend the capabilities of the language. Traditional languages are not usually extensible. Without unnatural convolutions, you cant bundle together both X and Y coordinates into a single variable called Point, and then add and lift off values of this type. The result is that traditional programs are more complex to write and maintain. The object oriented approach The fundamental idea behind object-oriented languages is to combine into a single unit both data and the functions that operate on that data.Such a unit is called an object. An objects functions, called process methods in Java, typically provide the only way to access its data. If you want to read the item and return the value to you, you call a member function in the object. It will read the item and return the value to you. You cant access the data directly. The data is hidden, so it is safe from accidental modification. Data and its functions are said to be encapsulated into a single entity. Data encapsulation and data hiding are key terms in the description of object oriented langua ges.If you want to modify the data in an object, you know exactly what functions interact with it the member functions in the object. No other functions can access the data. This simplifies writing, debugging, and maintaining the program. A Java program typically consists of a number of objects, which communicate with each other by calling one anothers members functions. We should mention that what are called member functions in C++ are called methods in Java. Also, data items are referred to as instance variables. handicraft an objects member function is referred to as sending a message to the object.