Implementing syntax coloring using the StyledText API

[Java Tip]

Code:

import java.util.*;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This class implements syntax coloring using the StyledText API
 */
public class SyntaxTest {
  // Punctuation
  private static final String PUNCTUATION = "(){};!&|.+-*/";

  // Color for the StyleRanges
  private Color red;

  /**
   * Runs the application
   */
  public void run() {
    Display display = new Display();
    Shell shell = new Shell(display);

    // Get color for style ranges
    red = display.getSystemColor(SWT.COLOR_RED);

    createContents(shell);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }

    // No need to dispose red

    display.dispose();
  }

  /**
   * Creates the main window contents
   * 
   * @param shell the main window
   */
  private void createContents(Shell shell) {
    shell.setLayout(new FillLayout());

    // Create the StyledText
    final StyledText styledText = new StyledText(shell, SWT.BORDER);

    // Add the syntax coloring handler
    styledText.addExtendedModifyListener(new ExtendedModifyListener() {
      public void modifyText(ExtendedModifyEvent event) {
        // Determine the ending offset
        int end = event.start + event.length - 1;

        // If they typed something, get it
        if (event.start <= end) {
          // Get the text
          String text = styledText.getText(event.start, end);

          // Create a collection to hold the StyleRanges
          java.util.List ranges = new java.util.ArrayList();

          // Turn any punctuation red
          for (int i = 0, n = text.length(); i < n; i++) {
            if (PUNCTUATION.indexOf(text.charAt(i)) > -1) {
              ranges.add(new StyleRange(event.start + i, 1, red, null, SWT.BOLD));
            }
          }

          // If we have any ranges to set, set them
          if (!ranges.isEmpty()) {
            styledText.replaceStyleRanges(event.start, event.length,
                (StyleRange[]) ranges.toArray(new StyleRange[0]));
          }
        }
      }
    });
  }

  /**
   * The application entry point
   * 
   * @param args the command line arguments
   */
  public static void main(String[] args) {
    new SyntaxTest().run();
  }
}
//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)

/**
 * This class contains information for syntax coloring and styling for an
 * extension
 */
class SyntaxData {
  private String extension;
  private Collection keywords;
  private String punctuation;
  private String comment;
  private String multiLineCommentStart;
  private String multiLineCommentEnd;

  /**
   * Constructs a SyntaxData
   * 
   * @param extension the extension
   */
  public SyntaxData(String extension) {
    this.extension = extension;
  }

  /**
   * Gets the extension
   * 
   * @return String
   */
  public String getExtension() {
    return extension;
  }

  /**
   * Gets the comment
   * 
   * @return String
   */
  public String getComment() {
    return comment;
  }

  /**
   * Sets the comment
   * 
   * @param comment The comment to set.
   */
  public void setComment(String comment) {
    this.comment = comment;
  }

  /**
   * Gets the keywords
   * 
   * @return Collection
   */
  public Collection getKeywords() {
    return keywords;
  }

  /**
   * Sets the keywords
   * 
   * @param keywords The keywords to set.
   */
  public void setKeywords(Collection keywords) {
    this.keywords = keywords;
  }

  /**
   * Gets the multi-line comment end
   * 
   * @return String
   */
  public String getMultiLineCommentEnd() {
    return multiLineCommentEnd;
  }

  /**
   * Sets the multi-line comment end
   * 
   * @param multiLineCommentEnd The multiLineCommentEnd to set.
   */
  public void setMultiLineCommentEnd(String multiLineCommentEnd) {
    this.multiLineCommentEnd = multiLineCommentEnd;
  }

  /**
   * Gets the multi-line comment start
   * 
   * @return String
   */
  public String getMultiLineCommentStart() {
    return multiLineCommentStart;
  }

  /**
   * Sets the multi-line comment start
   * 
   * @param multiLineCommentStart The multiLineCommentStart to set.
   */
  public void setMultiLineCommentStart(String multiLineCommentStart) {
    this.multiLineCommentStart = multiLineCommentStart;
  }

  /**
   * Gets the punctuation
   * 
   * @return String
   */
  public String getPunctuation() {
    return punctuation;
  }

  /**
   * Sets the punctuation
   * 
   * @param punctuation The punctuation to set.
   */
  public void setPunctuation(String punctuation) {
    this.punctuation = punctuation;
  }
}
//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)

/**
 * This class manages the syntax coloring and styling data
 */
class SyntaxManager {
  // Lazy cache of SyntaxData objects
  private static Map data = new Hashtable();

  /**
   * Gets the syntax data for an extension
   */
  public static synchronized SyntaxData getSyntaxData(String extension) {
    // Check in cache
    SyntaxData sd = (SyntaxData) data.get(extension);
    if (sd == null) {
      // Not in cache; load it and put in cache
      sd = loadSyntaxData(extension);
      if (sd != null) data.put(sd.getExtension(), sd);
    }
    return sd;
  }

  /**
   * Loads the syntax data for an extension
   * 
   * @param extension the extension to load
   * @return SyntaxData
   */
  private static SyntaxData loadSyntaxData(String extension) {
    SyntaxData sd = null;
    try {
      ResourceBundle rb = ResourceBundle.getBundle("examples.ch11." + extension);
      sd = new SyntaxData(extension);
      sd.setComment(rb.getString("comment"));
      sd.setMultiLineCommentStart(rb.getString("multilinecommentstart"));
      sd.setMultiLineCommentEnd(rb.getString("multilinecommentend"));

      // Load the keywords
      Collection keywords = new ArrayList();
      for (StringTokenizer st = new StringTokenizer(rb.getString("keywords"), " "); st
          .hasMoreTokens();) {
        keywords.add(st.nextToken());
      }
      sd.setKeywords(keywords);

      // Load the punctuation
      sd.setPunctuation(rb.getString("punctuation"));
    } catch (MissingResourceException e) {
      // Ignore
    }
    return sd;
  }
}