binsearchtreedriver.java

数据结构与算法分析中binary search tree的JAVA代码 请需要的同学下载

import java.io.*;
import java.util.*;

public class BinSearchTreeDriver implements Process {

    protected final String IN_FILE_PROMPT =
        "In the Input line, please enter the path for the input file.";

    protected final String OUT_FILE_PROMPT =
        "In the Input line, please enter the path for the output file.";

    protected GUI gui;

    protected BinSearchTree myTree;

    protected Iterator itr;

    protected BufferedReader fileReader;

    protected PrintWriter fileWriter;

    protected int lineRead;


    // Postcondition: this BinSearchTreeDriver object has been initialized.
    public BinSearchTreeDriver() {

        lineRead = 0;
        gui = new GUI (this);
        gui.println (IN_FILE_PROMPT);

    } // default constructor


    // Postcondition: One line of input (containing either the input-file
    //                path or the output-file path) has been processed.
    public void processInput (String s) {

        final String FILE_NOT_FOUND_MESSAGE = "The file was not found.";

        final String IO_EXCEPTION_MESSAGE = "There was an IO exception.";

        try {

            gui.println (s);
            if (lineRead == 0) {

                 fileReader = new BufferedReader (new FileReader (s));
                 lineRead++;
                 gui.println (OUT_FILE_PROMPT);

            } // input-path line
            else if (lineRead == 1) {

                fileWriter = new PrintWriter (new FileWriter (s));
                readAndProcessInFile();

            } // output-path line

        } // try
        catch (FileNotFoundException e) {

            gui.print (FILE_NOT_FOUND_MESSAGE);

        } // catch FileNotFoundException
        catch (IOException e) {

                gui.print (IO_EXCEPTION_MESSAGE + e);

        } // catch IOException

    } // method processInput


    // Postcondition: All of the method calls in the input file have been 
    //                read in and processed.
    public void readAndProcessInFile() throws IOException {

	final String TREE_MESSAGE = "Here is the BinSearchTree:\n";

        final String LINE_MESSAGE = "The line is:\n";

        final String CLOSE_WINDOW_PROMPT = "\nThe execution of this project  "
          +  "has been completed. Please close this window when you are ready.";

        Iterator tempItr;

        String line = fileReader.readLine();

        while (line != null) {

            fileWriter.println (LINE_MESSAGE + line);
            callMethod (line);
            fileWriter.print (TREE_MESSAGE);
            tempItr = myTree.iterator();
            while (tempItr.hasNext())
                fileWriter.println (tempItr.next());
            fileWriter.println ("\n\n\n");
            line = fileReader.readLine();

	} // while line != null
        fileWriter.close();
        gui.println (CLOSE_WINDOW_PROMPT);
        gui.freeze();

    } // method readAndProcess


    // Postcondition: The method in line has been processed.
    void callMethod (String line) throws IOException {

        final String CONSTRUCTOR = "BinSearchTree";

        final String CONSTRUCTOR_MESSAGE =
            "This BinSearchTree object has been constructed.";

        final String SIZE = "size";

        final String SIZE_MESSAGE =
          "The size of this BinSearchTree object is ";

        final String IS_EMPTY = "isEmpty";

        final String IS_EMPTY_MESSAGE =
          "This BinSearchTree object is empty? ";

        final String ITERATOR = "iterator";

        final String ITERATOR_MESSAGE =
            "This iterator has been constructed.";

        final String CONTAINS = "contains";

        final String CONTAINS_MESSAGE =
            " is contained in this BinSearchTree object? ";

        final String ADD = "add";

        final String ADD_MESSAGE =
            " has been inserted into this BinSearchTree object? ";

        final String REMOVE = "remove";

        final String REMOVE_MESSAGE =
            " has been removed from this BinSearchTree object? ";

        final String HAS_NEXT = "hasNext";

        final String HAS_NEXT_MESSAGE =
            "This iterator is not positioned beyond the end of " +
            "the BinSearchTree object? ";

        final String NEXT = "next";

        final String NEXT_MESSAGE =
            "The element returned by this iterator's next method is ";

        final String ITR_REMOVE_MESSAGE =
            "The element last returned by this iterator has been " +
            "removed from the BinSearchTree object.";

        StringTokenizer tokens = new StringTokenizer (line);
        String method = tokens.nextToken();
        Integer element;

        try {

            if (method.equals (CONSTRUCTOR)) {

                myTree = new BinSearchTree();
                fileWriter.println (CONSTRUCTOR_MESSAGE);

            } // constructor
            else if (method.equals (SIZE))
                fileWriter.println(SIZE_MESSAGE + myTree.size());
            else if (method.equals (IS_EMPTY))
                fileWriter.println (IS_EMPTY_MESSAGE + myTree.isEmpty());
            else if (method.equals (ITERATOR)) {

                itr = myTree.iterator();
                fileWriter.println (ITERATOR_MESSAGE);

            } // iterator method
            else if (method.equals (CONTAINS)) {

                element = new Integer (tokens.nextToken());
                fileWriter.println (element + CONTAINS_MESSAGE +
                                    myTree.contains (element));

            } // contains method
            else if (method.equals (ADD)) {

                element = new Integer (tokens.nextToken());
                fileWriter.println (element + ADD_MESSAGE +
                                    myTree.add (element));

            } // method add
            else if (method.equals (REMOVE)) {

                if (tokens.hasMoreTokens()) {

                    element = new Integer (tokens.nextToken());
                    fileWriter.println (element + REMOVE_MESSAGE +
                                        myTree.remove (element));

                } // method remove in BinSearchTree class
                else {

                    itr.remove();
                    fileWriter.println (ITR_REMOVE_MESSAGE);

                } // method remove in itr's class
            } // a remove method
            else if (method.equals (HAS_NEXT))
                fileWriter.println (HAS_NEXT_MESSAGE + itr.hasNext());
            else if (method.equals (NEXT))
                fileWriter.println (NEXT_MESSAGE + (Integer)itr.next());

        } // try
        catch (NoSuchElementException e) {

            final String MISSING_ELEMENT_MESSAGE =
                "An element should have been supplied for this method call.";

            fileWriter.println (e + MISSING_ELEMENT_MESSAGE);

        } // catch NoSuchElementException
        catch (NumberFormatException e) {

            final String INTEGER_NEEDED_MESSAGE =
                "The element should be an integer.";

            fileWriter.println (e + INTEGER_NEEDED_MESSAGE);

        } // catch NumberFormatException

    } // method callMethod


} // class BinSearchTreeDriver