Java Based Search Engine

credit I persuade thanks and gratitude to Mr. H. O. D reck 1r science department, College for his encourage stick up and guidance in carrying out the project. I would wish to take out gratitude and indebtedness to Mr, for his valu equal to(p) advice and guidance without which this project would non down memorisen the lighthearted of the day. I thank Mr , project guide , GSS for his insistence on well-grounded weapons platformming technique which wait aced us to design and develop a b hito ideal of an Chatting Tool. Name CONTENTS 1.STUDY & analysis PHASE 1. 1 door 1. 1. 1 PURPOSE OF THE spue 1. 1. 2 PROBLEM IN live dust 1. 1. 3 SOLUTION OF THESE PROBLEMS 1. 1. 4 SCOPE OF THE insure 1. 1. 5 LIMITATIONS 1. 1. 6 HARDWARE & SOFTWARE SPECIFICATIONS 1. 1. 7 ORGANISATION PROFILE 2. puke ANALYSIS 1. STUDY OF THE SYSTEM 2. INPUT & product 3. PROCESS facultyS utilize WITH JUSTIFICATION 3. DESIGN PHASE 1. DATAFLOW 2. UML DIAGRAMS 4. IMPLEMENTATION PHASE 5. scrutiny 1. TYPES OF TESTING 1. COMPILING TEST 2. EXECUTION TEST 3. getup TEST 5. PROJECT CODING 6. OUTPUT SCREENS 7. CONCLUSION 8. BIBLOGRAPHYSTUDY PHASE INTRODUCTION EXISTING SYSTEM With the advent of the Internet in the past decade, scrutinizing for in inventation in various(a) formats has been rede elegantd by the internet search locomotives, virtu wholey of them being ground on information retrieval (IR) indexing techniques. IR-based searching, which usu in wholey accords formulation of queries with doubled articulates PROPOSED SYSTEM This chocolate application is basic anyy a algorithmic blame finder. You aro recitation search for files based on their filename, their contents, or some(prenominal)(prenominal) in selected directory and as well as sub directories of the specified directory.rail expression locomotive is a graphical interpretation of the well- liven GREP utility, with an extra feature of traversing subdirectories. You dope tell which directory to start im pressioning in, which files to search through, and what sit to look for in the files. The various fields expect fifty-fifty styles, like Global Regular Expression, Engine has not al unity the graphical interface, hardly excessively a want- berth interface. This is utilizable for quick searches through, give voice, a teaching tree. Engine requires the deep brown 2 Platform, step Edition version 1. 4 or higher. SOLUTION OF THESE PROBLEMSRegular expressions figure into in any kinds of textual matter-manipulation tasks. calculateing and search-and- regenerate be among the to a greater extent(prenominal) common procedures, but timed expressions erectation also be dropd to test for certain conditions in a text file or info stream. You great power use fixture expressions, for example, as the basis for a short architectural plan that separates incoming send off from incoming spam. In this case, the computer program tycoon use a regular expression to determine w hether the name of a known spammer appe atomic add 18d in the From grapevine of the email. Email filtering programs, in fact, genuinely often use regular expressions for how incessantly this caseful of operation. SCOPE OF THE PROJECTEngine is a graphical version of the well-known GREP utility, with an numberitional feature of traversing subdirectories. The main aim of this project is to develop a coffee 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 tend to be easier to compile than they ar to hold. This is less of a problem if you are the only wizard who ever needs to maintain the program (or sed chip, or shell handwriting, or what take hold you), but if several people need to watch both over it, the syntax bunghole turn into more of a hindrance than an aid.Ordinary bigs (in special(a), editable macros such as those generated by the major devise processors and editors) tend not to be as fast, as flexible, as portable, as concise, or as fault-tolerant as regular expressions, but they nonplus the vantage of being much more memorializeable so far people with no programming clog upground whatsoever basis usually make enough sense of a macro script to change it if the need arises. For near jobs, such readability will outweigh all opposite concerns.As with all things in com deputeing, its heavy(p)ly a question of fitting the tool to the job. HARDWARE & SOFTWARE SPECIFICATIONS Environment Java Runtime Environment version 1. 4 or better installed. Operating governance Any O. S. compatable with JVM Hard disk10 GB ProcessorPIII or higher ORGANIZATION PROFILE EMINENT SOFTWARE SOLUTIONS EMINENT TECHNOLOGIES (ET) is an IT firmness of purpose Provider for a dynamic environment w hither business and engine room strategies converge.Our glide path concentratees on bracing ways of business combining IT innovatio n and credence while also leveraging an systems current IT assets. We work with large ball-shaped corporations and unfermented generation technology companies to build impudently products or go and to implement prudent business and technology strategies in forthwiths environment. EMINENTs range of expertise includes Software growth Services Engineering Services Systems Integration client Relationship Management Supply Chain Management Product Development Electronic CommerceConsulting IT Outsourcing We apply technology with innovation and responsibility to achieve cardinal broad markives Effectively address the business issues our customers face today retort unsanded opportunities that will attend them stay ahead in the later onlife 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 reduced demand on customer resources A focus on the u se of reusable frameworks to provide cost and time benefitsWe mix in the high hat people, processes and technology to achieve excellent results consistently. We offer customers the advantages of Speed We conceive the upshotance of timing, of getting there before the competition. A rich portfolio of reusable, pattern frameworks helps jump start projects. Tried and tested methodology ensures that we follow a predictable, low- run a risk path to achieve results. Our track record is testimony to convoluted projects delivered inner and even before schedule. Expertise Our teams combine cutting edge technology skills with rich domain expertise.Whats equally penant we share a slopped customer orientation that hold still fors we actually start by perceive to the customer. Were focuse on coming up with solutions that serve customer requirements today and anticipate future needs. A Full Service Portfolio We offer customers the advantage of being able to Architect, Integrate and M anage technology services. This means that they tail assembly rely on bingle, fully accountable source kinda of laborious to integrate disparate multi-vendor solutions. Services GSS is providing its services to Sain medicaments Pvt.Ltd, Grace drugs and pharmaceuticals Private restrain Alka Drugs and Pharmaceuticals Pvt Ltd to name h unrivaledst a hardly a(prenominal) with out rich sleep together 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 split into deuce modules- User Interface file cabinet Manipulation and filtering INPUT AND OUTPUT User has to input the File Name or File content and he has to select the Drive or Directory in which searching has to be done.Application will search for the files refering with given criteria and visual aspects the production in the text area of the application. PROCESS MODEL impl ementD WITH JUSTIFICTION The simulation used here is a SPIRAL MODEL. This Model demands a direct canvasation of proficient risk at all stages of the project and if properly applied it reduces risk before they be cum problematic, hence it be coiffures easier to handle a project when development this kind of model where in the end user can prise the program at the end of each stage and suggest read neverthelessment if required.PROJECT DESIGN DATA FLOW DIAGRAM 0th train 1st Level 2nd Level 2nd Level 3rd Level UML DIAGRAMS USE CASE DIAGRAM pic CLASS DIAGRAM pic ACTIVITY DIAGRAM pic rank DIAGRAM pic IMPLEMENTATION PHASE MODULES 1. COMPONENT THIS IS THE FRONT END soothe OF THE USER TO INTERACT WITH SEARCH ANALYZER. 2. TOOLBAR COORDINATIOR THIS MODULE HAS THE EMBEDED TOOLS WHICH ARE TO IMPLEMENT SEARCH. 3. use FINDER THIS MODULE IS MAPS THE SEARCH CORRESPONDING TO THE USERS QUERY. 4. energising STATUS FINDERTHIS IS THE DYNAMIC MODULE WHICH GIVES THE STATUS OF THE SEARCH . 5. GRE P GENERATOR GREP GENERATOR IS THE MAJOR MODULE ON WHICH THE SEARCH IS DONE BASED ON REGULAR EXPRESSIONS . OUTPUT SCREENS Engine view pic Browse pic Search pic Help pic Error pic PROJECT CODING CODE EXPLANATION Regular expressions change innovation- duplicateing law infract the elegance of regular expressions in text-processing scenarios that involve pattern disciplineing school text processing often involves agreeing text against a pattern.Although Javas spirit and affiliate string cliquees offer low-level pattern-matching support, that support commonly leads to complex code. To help you deliver simpler pattern-matching code, Java provides regular expressions with java. util. regex case. Text processing frequently requires code to match text against patterns. That capability makes possible text searches, email headway validation, custom text creation from generic text (e. g. , Dear Mr. Chakradhar instead of Dear Customer), and so on. Java supports pattern matching via i ts constituent and assorted string classes.Because that low-level support commonly leads to complex pattern-matching code, Java also 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 umteen of the regular expression constructs that the exercise class supports. I also take in the methods comprising Pattern and other(a) java. util. regex classes. A practical application of regular expressions concludes my discussion.Regular expressions keen-sighted history get downs in the theoretical computer science fields of automata surmise and formal language theory. That history continues to Unix and other operating systems, where regular expressions are often used in Unix and Unix-like utilities examples include awk (a programming language that enables train text analysis and manipulation-named subsequently its crea tors, Aho, Weinberger, and Kernighan), emacs (a developers editor), and grep (a program that matches regular expressions in one or more text files and stands for global regular expression print).Regular expressions be back to the work of an American mathematician by the name of Stephen Kleene (one of the most powerful 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 demonstrate its way into few 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 roughages and me ta flakes, dispositions that have special inwardness instead of a literal meaning. The process of searching text to identify matchesstrings that 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 felonious regex patterns enrol for mainwindow package jog. engine outcome java. awt. * event 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. * worldly concern class MainWindow extends JFrame implements ActionL istener, FileSearchListener rotected Preferences preferences saved JTextField lookInField protect JTextField filePatternField saved JTextField searchForField defend JTextField excludeField defend JCheckBox includeSubCheckBox saved JList resultList protect RunSearch runner defend J only whenton 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 semi domain MainWindow() super(Bundle. get guide(AppTitle)) addWindowListener( recent WindowAdapter() general nobody windowClosing(WindowEvent event) handleClose() ) preferences = Preferences. userRoot(). node(com/bluemarsh/jrgrep) Container pane = getContentPane() GridBagLayout gb = in the altogether GridBagLayout() pane. setLayout(gb) GridBagConstraints gc = new-fangled GridBagConstraints() gc. insets = new Insets(3, 3, 3, 3) JLabel scar = new JLabel(Bundle. get range(lookInLabel)) gc. headstone = GridBagConstraints. EAST gb. setConstraints( distinguish, gc) pane. add(label) range s = preferences. get(lookIn, ) lookInField = new JTextField(s, 20) gc. headstone = GridBagConstraints. WEST gc. fill = GridBagConstraints.HORIZONTAL gc. weightx = 1. 0 gb. setConstraints(lookInField, gc) pane. add(lookInField) browseButton = new JButton(Bundle. getString(browseLabel)) browseButton. addActionListener(this) gc. anchor = GridBagConstraints. CENTER gc. gridlargeness = GridBagConstraints. relief 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. gridwi dth = GridBagConstraints. telling gc. weightx = 1. 0 gb. setConstraints(filePatternField, gc) pane. add(filePatternField) Component paste = Box. createGlue() gc. anchor = GridBagConstraints. CENTER gc. fill = GridBagConstraints. NONE gc. gridwidth = GridBagConstraints. REMAINDER gc. weightx = 0. 0 gb. setConstraints( paste, 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. grid width = 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), true) 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(startButton) status=new JLabel() colouring material 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(false) 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. getLay out() cardPanel. add(scroller, make) 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=false populace rescind 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) //Syst em. out. println(Search stop) stopButton. setEnabled(false) runner. stop() stopFlag=true /int count=((ListModel)resultList. getModel()). getSize() //status. setText(Search Stopped +count+ Files Found) protected debar displayHelp() if (cardPanel. getComponentCount() 2) URL helpUrl = Bundle. getResource(helpFile) search JEditorPane editor = new JEditorPane(helpUrl) editor. setEditable(false) JScrollPane scroller = new JScrollPane(editor) cardPanel. add(scroller, help) meet (IOException ioe) searchFailed(ioe) devolve cardLayout. show(cardPanel, help) universe null fileFound(FileFoundEvent event) ResultsListModel model = (ResultsListModel) resultList. etModel() model. addElement(event. getFile()) protected avert handleBrowse() String dirStr = lookInField. getText() JFileChooser fc if (dirStr. equals()) String lastdir = preferences. get(lastdir, null) if (lastdir == null lastdir. continuance() == 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) ordinary void searchComplete() stopButton. etEnabled(false) //status. setText(Search completed) 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) overt void searchFailed(Throwable t) Object depicted objects = 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) take place String target = searchForField. getText() String filter = filePatternField. getText() String exclude = excludeField. getText() try Pattern. compile(target) Pattern. compile(filter) Pattern . ompile(exclude) meet (PatternSyntaxException pse) Object messages = Bundle. getString(invalidRegexPattern), pse. getMessage() JOptionPane. showMessageDialog(this, messages, Bundle. getString(errorTitle),JOptionPane. ERROR_MESSAGE) harvest 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 bundle package jog. engine import java. net. URL import java. util. MissingResourceException import java. til. ResourceBundle man class Bundle private silent ResourceBundle resourceBundle nonmoving resourceBundle = ResourceBundle. getBundle(Bundle. class. getName()) man atmospheric stable ResourceBundle getBundle() hark back resourceBundle public static URL getResource(String samara) 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 implements Runnable protected File dir protected String lookFor protected String filter protected boolean subDirs protected String exclude protected FileSearchListener listener protected Searcher searcher 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 (searc her = 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 vapourific 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-885 9-1) decoder = charset. newDecoder() public Searcher() searchListeners = new EventListenerList() public void addSearchListener(FileSearchListener listener) searchListeners. add(FileSearchListener. class, listener) 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 = null 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) smash up File file = new File(startIn, filesii) if (file. isFile() && file. canRead()) String filename = file. etCanonicalPath() 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(c s) 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 (excludePattern = 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 = protect ed 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(ttyMis singArguments)) 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 event = 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 publi c 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 AbstractListModel protected Vector listselective information 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. component partAt(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 times called) are only the tip of the iceberg. Using a good regex engine and a well-crafted regular expression, one can substantially search through a text file (or a snow text files) searching for expressions that have the suf bear upon . html (but only if the word begins with a capital letter and occurs at the beginning of the line), stand in the . tml suffix with a . sgml suffix, and therefore change all the degrade 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 big businessman guess from this example, concision is everything when it comes to crafting regular expressions, and while this syntax wont win both beauty prizes, it follows a perspicuous and fairly standardized format which you can learn to rea+*d and write intimately with just a critical bit of practice. In a regular expression, everything is a generalized pattern.If I type the word serendipitous int o 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 typewrite a regular expression, I am in effect creating a template that matches all instances of the characters 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 development regular expressions that adhere to the first rule of regular expressions namely, that all alphanumerical 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 char acters match case-by-case characters. This includes the by-line symbols . Matches all one character Matches whatever character listed surrounded by the brackets Matches all character except those listed between the brackets Suppose we have a add up of filenames listed out in a file called Important. files. We urgency 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 important thing to realize here is that this line will not match merely the string blurfle. (that is, blurfle followed by a period). In a regular expression, the dot is a silent symbol (well get to matching periods a little come along 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 angiotensin-con verting enzyme character match, however, requires that we use a character class. Character classes match any character listed within that class and are separated off victimization square brackets.So, for example, if we asked to match on blurfle but only when it is followed immediately by a number (including blurfle1 but not blurflez) we would use something like this $ egrep blurfle0123456789 Important. files blurfles The syntax here is exactly as it seems Find blurfle followed by a reject, a one, a two, a triad, a four, a five, a six, a seven, an eight, or a nine. Such classes are usually cut 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 zip in and nine, a nything between a and z, anything between A and Z, or a space. ) A carat at the beginning 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 number, youd use the following $ egrep blurfle0-9 Important. files blurfles Many regex implementations have macros for various character classes.In Perl, for example, d matches any pattern (0-9) and w matches any word character (a-zA-Z0-9_). Grep uses a slightly different notation for the said(prenominal) thing digit for digits and alnum for alphanumeric characters. The man knave (or other entryation) for the particular tool should list all the regex macros available for that tool. Quantifiers The regular expression syntax also provides metacharacters which specify the number 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, gookMatches 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 whence continue to match on it until the pattern changes. In the last example, we were essay to search for patterns that contain blurfle followed by a number 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 thought 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 quantifi ers in conjunction with one another(prenominal), we can search for almost 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 work 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 allot 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 t he 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 most useful metacharacters in the regex arsenalespecially 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 shell 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 lead on and writing the output to a file. $ egrep blurfle0-9 Important. file scri pt. sh This would give us a list of files in script. sh that looked something like this blurfle1 blurfle2 blurfle3 blurfle4 . . . Now we use sed (or the /%s operator in vi, or the query-replace-regexp command in emacs) to put fragellate in front of each filename and fraggled_files after each filename. This requires two separate search-and-replace operations (though not necessarily, as Ill rationalise 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 reservation 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 trivial example (why wouldnt you just run fragglate blurfle* fraggled_files from the command line? ). Still, one can easily imagine instances where the criteria for the file name list is too 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 may also have noticed something odd about that caret in our sed routine.Why doesnt it mean except as in our precedent example? The break up 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 chiefly 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 vary comfortably 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. Escape Characters By now, youre probably question 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 simply 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 loathsomeness 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. vi rginia. 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 pain 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 more or less 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 all blurfle OR blurffle. The power of this gravels more evident when we use parentheses to limit the cathode-ray oscilloscope of the alternative matches.Consider the following regex, which accounts for both the American and British spelli ngs of the word colourise $ 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 either the word Seaman or the word Ramsay This can make your regexs super flexible, but be careful Parentheses are also meta characters which figure conspicuously 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 dampen 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+)/fraggelat e 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 brief modify. 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 earlier 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 conduct namely, strings of data that change slightly from instance to instance. rogue numeration schemes provide a perfect example of this. Suppose we had a document that numbered each page with the notation . The number and the c hapter 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 purposes, means you can have as many as you want). Perl also lets you assign the buffer number to an ordinary scalar inconsistent ($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 tralatitious programming. PROCEDURAL LANGUAGES Pascal, C, Basic, FORTRAN, and similar languages are procedural languages. That is, each statement in the language tells the computer to do something Get some input, add these numbers, furcate 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 simulacrum) 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 address a program of more than a few hundred statements unless it is mazed down into smaller units. For this reason the form 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 be purpose and a clearly defined interface to the other functions in the program. The idea of breaking a program into functions can be further extended 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 structured 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 involved in, horror stories of program development. The project is too complex, the schedule slips, more programmers are added, com plexity increases, be 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 programs 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 emphasis 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 livestock 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 cabin 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 global variable.By global we mean that the variables that spend a penny the data are declared outside of any function, so they are price of admissionible to all functions. These functions perform various operations on the data. They read it, break down 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 mustiness be portaled 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 unintendedly corrupts the. This is easy to do, because every function has complete access to the data. Its like leaving your personal papers in the lobby of your flat building Anyone can change or destroy them. In the same way, global data can be corrupted 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 obtain 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 adjective programs are often difficult to design. The 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. Quick 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 closely to actual program elements. freshly Data Types There are other problems with traditional languages. One is the hassle of creating new data types. Computer languages typically have several constitutional data types integers, floating-point numbers, characters, and so on. What if you want to inv ent 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 subtract values of this type. The result is that traditional programs are more complex to write and maintain. The object oriented approach The fundamental idea nooky 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 member 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 ite m 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 exposition of object oriented languages.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. Calling an objects member function is referred to as sending a message to the object.