Java tutorial
/** * This file belongs to the BPELUnit utility and Eclipse plugin set. See enclosed * license file for more information. * */ package net.bpelunit.toolsupport.editors.wizards.fields; import org.eclipse.jface.dialogs.IDialogConstants; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.core.runtime.Assert; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Label; /** * Base class of all dialog fields. Dialog fields manage controls together with the model, * independed from the creation time of the widgets. - support for automated layouting. - enable / * disable, set focus a concept of the base class. * * DialogField have a label. */ public class DialogField { private Label fLabel; protected String fLabelText; private IDialogFieldListener fDialogFieldListener; private boolean fEnabled; public DialogField() { fEnabled = true; fLabel = null; fLabelText = ""; } /** * Sets the label of the dialog field. */ public void setLabelText(String labeltext) { fLabelText = labeltext; if (isOkToUse(fLabel)) { fLabel.setText(labeltext); } } // ------ change listener /** * Defines the listener for this dialog field. */ public final void setDialogFieldListener(IDialogFieldListener listener) { fDialogFieldListener = listener; } /** * Programatical invocation of a dialog field change. */ public void dialogFieldChanged() { if (fDialogFieldListener != null) { fDialogFieldListener.dialogFieldChanged(this); } } // ------- focus management /** * Tries to set the focus to the dialog field. Returns <code>true</code> if the dialog field * can take focus. To be reimplemented by dialog field implementors. */ public boolean setFocus() { return false; } /** * Posts <code>setFocus</code> to the display event queue. */ public void postSetFocusOnDialogField(Display display) { if (display != null) { display.asyncExec(new Runnable() { public void run() { setFocus(); } }); } } // ------- layout helpers /** * Creates all controls of the dialog field and fills it to a composite. The composite is * assumed to have <code>MGridLayout</code> as layout. The dialog field will adjust its * controls' spans to the number of columns given. To be reimplemented by dialog field * implementors. */ public Control[] doFillIntoGrid(Composite parent, int nColumns) { assertEnoughColumns(nColumns); Label label = getLabelControl(parent); label.setLayoutData(gridDataForLabel(nColumns)); return new Control[] { label }; } /** * Returns the number of columns of the dialog field. To be reimplemented by dialog field * implementors. */ public int getNumberOfControls() { return 1; } protected static GridData gridDataForLabel(int span) { GridData gd = new GridData(GridData.HORIZONTAL_ALIGN_FILL); gd.horizontalSpan = span; return gd; } protected boolean hasLabel() { return (fLabelText != null) && !"".equals(fLabelText); } // ------- ui creation /** * Creates or returns the created label widget. * * @param parent The parent composite or <code>null</code> if the widget has already been * created. */ public Label getLabelControl(Composite parent) { if (fLabel == null) { assertCompositeNotNull(parent); fLabel = new Label(parent, SWT.LEFT | SWT.WRAP); fLabel.setFont(parent.getFont()); fLabel.setEnabled(fEnabled); if (fLabelText != null && !"".equals(fLabelText)) { //$NON-NLS-1$ fLabel.setText(fLabelText); } else { // XXX: to avoid a 16 pixel wide empty label - revisit fLabel.setText("."); //$NON-NLS-1$ fLabel.setVisible(false); } } return fLabel; } /** * Creates a spacer control. * * @param parent The parent composite */ public static Control createEmptySpace(Composite parent) { return createEmptySpace(parent, 1); } /** * Creates a spacer control with the given span. The composite is assumed to have * <code>MGridLayout</code> as layout. * * @param parent The parent composite */ public static Control createEmptySpace(Composite parent, int span) { Label label = new Label(parent, SWT.LEFT); GridData gd = new GridData(); gd.horizontalAlignment = GridData.BEGINNING; gd.grabExcessHorizontalSpace = false; gd.horizontalSpan = span; gd.horizontalIndent = 0; gd.widthHint = 0; gd.heightHint = 0; label.setLayoutData(gd); return label; } /** * Tests is the control is not <code>null</code> and not disposed. */ protected final boolean isOkToUse(Control control) { return (control != null) && (Display.getCurrent() != null) && !control.isDisposed(); } // --------- enable / disable management /** * Sets the enable state of the dialog field. */ public final void setEnabled(boolean enabled) { if (enabled != fEnabled) { fEnabled = enabled; updateEnableState(); } } /** * Called when the enable state changed. To be extended by dialog field implementors. */ protected void updateEnableState() { if (fLabel != null) { fLabel.setEnabled(fEnabled); } } /** * Brings the UI in sync with the model. Only needed when model was changed in different thread * whil UI was lready created. */ public void refresh() { updateEnableState(); } /** * Gets the enable state of the dialog field. */ public final boolean isEnabled() { return fEnabled; } protected final void assertCompositeNotNull(Composite comp) { Assert.isNotNull(comp, "uncreated control requested with composite null"); //$NON-NLS-1$ } protected final void assertEnoughColumns(int nColumns) { Assert.isTrue(nColumns >= getNumberOfControls(), "given number of columns is too small"); //$NON-NLS-1$ } protected String getLabelText() { return fLabelText; } /** * Returns a width hint for a button control. */ public int getButtonWidthHint(Button button) { button.setFont(JFaceResources.getDialogFont()); PixelConverter converter = new PixelConverter(button); int widthHint = converter.convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH); return Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x); } }