public interface ISaveablePart {
    ...
    /**
     * Returns whether the contents of this part have changed since the last save
     * operation. If this value changes the part must fire a property listener 
     * event with <code>PROP_DIRTY</code>.
     * <p>
     * <b>Note:</b> this method is called often on a part open or part
     * activation switch, for example by actions to determine their 
     * enabled status.
     * </p>
     *
     * @return <code>true</code> if the contents have been modified and need
     *   saving, and <code>false</code> if they have not changed since the last
     *   save
     */
    public boolean isDirty();
    ...
}

public abstract class FormEditor extends MultiPageEditorPart implements IPageChangeProvider {
    ...
    public boolean isDirty() {
        if (pages != null) {
            for (int i = 0; i < pages.size(); i++) {
                Object page = pages.get(i);
                if (page instanceof IFormPage) {
                    IFormPage fpage = (IFormPage) page;
                    if (fpage.isDirty())
                        return true;
                }
            }
        }
        return super.isDirty();
    }
    ...
}

public class FormDesignerEditor extends FormEditor {
    ...
    @Override
    public void doSave(IProgressMonitor monitor) {
        commitPages(true);
        editorDirtyStateChanged();
    }
    ...
}
}

public class FieldsMasterSectionPart extends SectionPart implements IPartSelectionListener {
    ...
    @Override
    public void commit(boolean onSave) {
        super.commit(onSave);

        if (!onSave) {
            return;
        }

        assert (!(getManagedForm().getInput() instanceof IFileEditorInput));

        try {
            ((IFileEditorInput) getManagedForm().getInput()).getFile().setContents(
                    new ByteArrayInputStream(
                            formatYAMLString(getYAML()).getBytes("UTF-8")),  //$NON-NLS-1$
                    true,
                    false,
                    null);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (CoreException e) {
            e.printStackTrace();
        }
    }
    ...
}

- name: name
  description: 名前
  required:
    message: 名前は必須です。
- name: email
  description: メールアドレス
  required:
    message: メールアドレスは必須です。
  validator:
    - name: Email
      rule:
        allowDotBeforeAtmark: true
      message:
    - name: Compare
      rule:
        to: email2
      message: 確認用メールアドレスと一致しません。
- name: email2
  description: 確認用メールアドレス
  required:
    message: 確認用メールアドレスは必須です。

public class FieldsMasterSectionPart extends SectionPart implements IPartSelectionListener {
    ...
    private void createTable(Composite composite) {
        ...
        fViewer.addSelectionChangedListener(new ISelectionChangedListener() {
            ...
        });

        setFieldTableFromYAMLFile();
    }

    private void setFieldTableFromYAMLFile() {
        assert (!(getManagedForm().getInput() instanceof IFileEditorInput));

        BufferedInputStream bufferedIn = null;
        ByteArrayOutputStream byteOut = null;
        try {
            bufferedIn = new BufferedInputStream(
                    ((IFileEditorInput) getManagedForm().getInput()).getFile()
                        .getContents(true));
            byteOut = new ByteArrayOutputStream();
            int read = 0;
            while ((read = bufferedIn.read()) != -1) {
                byteOut.write(read);
            }

            List<Map<String, Object>> fieldList = (List<Map<String, Object>>) Yaml.load(byteOut.toString("UTF-8"));
            for (Map<String, Object> fieldMap : fieldList) {
                fViewer.add(getField(fieldMap));
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (CoreException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedIn != null) {
                    bufferedIn.close();
                }
            } catch (IOException ioe) {
            }
            try {
                if (byteOut != null) {
                    byteOut.close();
                }
            } catch (IOException ioe) {
            }
        }
    }
}