fieldeditor.java

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    /**
     * Returns the label control. 
     *
     * @return the label control, or <code>null</code>
     *  if no label control has been created
     */
    protected Label getLabelControl() {
        return label;
    }

    /**
     * Returns this field editor's label component.
     * <p>
     * The label is created if it does not already exist
     * </p>
     *
     * @param parent the parent
     * @return the label control
     */
    public Label getLabelControl(Composite parent) {
        if (label == null) {
            label = new Label(parent, SWT.LEFT);
            label.setFont(parent.getFont());
            String text = getLabelText();
            if (text != null) {
				label.setText(text);
			}
            label.addDisposeListener(new DisposeListener() {
                public void widgetDisposed(DisposeEvent event) {
                    label = null;
                }
            });
        } else {
            checkParent(label, parent);
        }
        return label;
    }

    /**
     * Returns this field editor's label text.
     *
     * @return the label text
     */
    public String getLabelText() {
        return labelText;
    }

    /**
     * Returns the number of basic controls this field editor consists of.
     *
     * @return the number of controls
     */
    public abstract int getNumberOfControls();

    /**
     * Returns the name of the preference this field editor operates on.
     *
     * @return the name of the preference
     */
    public String getPreferenceName() {
        return preferenceName;
    }

    /**
     * Returns the preference page in which this field editor
     * appears.
     *
     * @return the preference page, or <code>null</code> if none
     * @deprecated use #getPage()
     */
    protected PreferencePage getPreferencePage() {
    	if(page != null && page instanceof PreferencePage) {
			return (PreferencePage) page;
		}
    	return null;
    }
    
    /**
     * Return the DialogPage that the receiver is sending
     * updates to.
     * 
     * @return DialogPage or <code>null</code> if it 
     * has not been set.
     * 
     * @since 3.1
     */
    protected DialogPage getPage(){
    	return page;
    }

    /**
     * Returns the preference store used by this field editor.
     *
     * @return the preference store, or <code>null</code> if none
     * @see #setPreferenceStore
     */
    public IPreferenceStore getPreferenceStore() {
        return preferenceStore;
    }

    /**
     * Initialize the field editor with the given preference name and label.
     * 
     * @param name the name of the preference this field editor works on
     * @param text the label text of the field editor
     */
    protected void init(String name, String text) {
        Assert.isNotNull(name);
        Assert.isNotNull(text);
        preferenceName = name;
        this.labelText = text;
    }

    /**
     * Returns whether this field editor contains a valid value.
     * <p>
     * The default implementation of this framework method
     * returns <code>true</code>. Subclasses wishing to perform
     * validation should override both this method and
     * <code>refreshValidState</code>.
     * </p>
     * 
     * @return <code>true</code> if the field value is valid,
     *   and <code>false</code> if invalid
     * @see #refreshValidState()
     */
    public boolean isValid() {
        return true;
    }

    /**
     * Initializes this field editor with the preference value from
     * the preference store.
     */
    public void load() {
        if (preferenceStore != null) {
            isDefaultPresented = false;
            doLoad();
            refreshValidState();
        }
    }

    /**
     * Initializes this field editor with the default preference value
     * from the preference store.
     */
    public void loadDefault() {
        if (preferenceStore != null) {
            isDefaultPresented = true;
            doLoadDefault();
            refreshValidState();
        }
    }

    /**
     * Returns whether this field editor currently presents the
     * default value for its preference.
     * 
     * @return <code>true</code> if the default value is presented,
     *   and <code>false</code> otherwise
     */
    public boolean presentsDefaultValue() {
        return isDefaultPresented;
    }

    /**
     * Refreshes this field editor's valid state after a value change
     * and fires an <code>IS_VALID</code> property change event if
     * warranted.
     * <p>
     * The default implementation of this framework method does
     * nothing. Subclasses wishing to perform validation should override
     * both this method and <code>isValid</code>.
     * </p>
     *
     * @see #isValid
     */
    protected void refreshValidState() {
    }

    /**
     * Sets the focus to this field editor.
     * <p>
     * The default implementation of this framework method
     * does nothing. Subclasses may reimplement.
     * </p>
     */
    public void setFocus() {
        // do nothing;
    }

    /**
     * Sets this field editor's label text.
     * The label is typically presented to the left of the entry field.
     *
     * @param text the label text
     */
    public void setLabelText(String text) {
        Assert.isNotNull(text);
        labelText = text;
        if (label != null) {
			label.setText(text);
		}
    }

    /**
     * Sets the name of the preference this field editor operates on.
     * <p>
     * The ability to change this allows the same field editor object
     * to be reused for different preferences.
     * </p>
     * <p>
     * For example: <p>
     * <pre>
     * 	...
     *  editor.setPreferenceName("font");
     * 	editor.load();
     * </pre>
     * </p>
     *
     * @param name the name of the preference
     */
    public void setPreferenceName(String name) {
        preferenceName = name;
    }

    /**
     * Sets the preference page in which this field editor
     * appears.
     *
     * @param preferencePage the preference page, or <code>null</code> if none
     * @deprecated use #setPage(DialogPage)
     */
    public void setPreferencePage(PreferencePage preferencePage) {
        setPage(preferencePage);
    }
    

    /**
     * Set the page to be the receiver.
	 * @param dialogPage
	 * 
	 * @since 3.1
	 */
	public void setPage(DialogPage dialogPage) {
		page = dialogPage;
		
	}

	/**
     * Sets the preference store used by this field editor.
     *
     * @param store the preference store, or <code>null</code> if none
     * @see #getPreferenceStore
     */
    public void setPreferenceStore(IPreferenceStore store) {
        preferenceStore = store;
    }

    /**
     * Sets whether this field editor is presenting the default value.
     *
     * @param booleanValue <code>true</code> if the default value is being presented,
     *  and <code>false</code> otherwise
     */
    protected void setPresentsDefaultValue(boolean booleanValue) {
        isDefaultPresented = booleanValue;
    }

    /**
     * Sets or removes the property change listener for this field editor.
     * <p>
     * Note that field editors can support only a single listener.
     * </p>
     *
     * @param listener a property change listener, or <code>null</code>
     *  to remove
     */
    public void setPropertyChangeListener(IPropertyChangeListener listener) {
        propertyChangeListener = listener;
    }

    /**
     * Shows the given error message in the page for this
     * field editor if it has one.
     *
     * @param msg the error message
     */
    protected void showErrorMessage(String msg) {
        if (page != null) {
			page.setErrorMessage(msg);
		}
    }

    /**
     * Shows the given message in the page for this
     * field editor if it has one.
     *
     * @param msg the message
     */
    protected void showMessage(String msg) {
        if (page != null) {
			page.setErrorMessage(msg);
		}
    }

    /**
     * Stores this field editor's value back into the preference store.
     */
    public void store() {
        if (preferenceStore == null) {
			return;
		}

        if (isDefaultPresented) {
            preferenceStore.setToDefault(preferenceName);
        } else {
            doStore();
        }
    }

    /**
     * Set the GridData on button to be one that is spaced for the
     * current font.
     * @param button the button the data is being set on.
     */

    protected void setButtonLayoutData(Button button) {

        GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);

        // Compute and store a font metric
        GC gc = new GC(button);
        gc.setFont(button.getFont());
        FontMetrics fontMetrics = gc.getFontMetrics();
        gc.dispose();

        int widthHint = org.eclipse.jface.dialogs.Dialog
                .convertVerticalDLUsToPixels(fontMetrics,
                        IDialogConstants.BUTTON_WIDTH);
        data.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT,
                SWT.DEFAULT, true).x);
        button.setLayoutData(data);
    }

    /**
     * Set whether or not the controls in the field editor
     * are enabled.
     * @param enabled The enabled state.
     * @param parent The parent of the controls in the group.
     *  Used to create the controls if required.
     */
    public void setEnabled(boolean enabled, Composite parent) {
        getLabelControl(parent).setEnabled(enabled);
    }

}