persistentdocument.java

<Apress.The.Definitive.Guide.to.SWT.and.JFace.eBook-LiB>书籍配套源代码

package examples.ch18.perledit.model;

import java.io.*;

import org.eclipse.jface.text.*;

/**
 * This class adds persistence to the Document class
 */
public class PersistentDocument extends Document implements IDocumentListener {
  private String fileName;
  private boolean dirty;

  /**
   * PersistentDocument constructor
   */
  public PersistentDocument() {
    addDocumentListener(this);
  }

  /**
   * Gets whether this document is dirty
   * 
   * @return boolean
   */
  public boolean isDirty() {
    return dirty;
  }

  /**
   * Gets the file name
   * 
   * @return String
   */
  public String getFileName() {
    return fileName;
  }

  /**
   * Sets the file name
   * 
   * @param fileName
   */
  public void setFileName(String fileName) {
    this.fileName = fileName;
  }

  /**
   * Saves the file
   * 
   * @throws IOException if any problems
   */
  public void save() throws IOException {
    if (fileName == null)
        throw new IllegalStateException("Can't save file with null name");
    BufferedWriter out = null;
    try {
      out = new BufferedWriter(new FileWriter(fileName));
      out.write(get());
      dirty = false;
    } finally {
      try {
        if (out != null) out.close();
      } catch (IOException e) {}
    }
  }

  /**
   * Opens the file
   * 
   * @throws IOException if any problems
   */
  public void open() throws IOException {
    if (fileName == null)
        throw new IllegalStateException("Can't open file with null name");
    BufferedReader in = null;
    try {
      in = new BufferedReader(new FileReader(fileName));
      StringBuffer buf = new StringBuffer();
      int n;
      while ((n = in.read()) != -1) {
        buf.append((char) n);
      }
      set(buf.toString());
      dirty = false;
    } finally {
      try {
        if (in != null) in.close();
      } catch (IOException e) {}
    }
  }

  /**
   * Clears the file's contents
   */
  public void clear() {
    set("");
    fileName = "";
    dirty = false;
  }

  /**
   * Called when the document is about to be changed
   * 
   * @param event the event
   */
  public void documentAboutToBeChanged(DocumentEvent event) {

  }

  /**
   * Called when the document changes
   * 
   * @param event the event
   */
  public void documentChanged(DocumentEvent event) {
    // Document has changed; make it dirty
    dirty = true;
  }
}