Property Editors and Customizers. COMP434 Software Design. Property Editors. Property Editors and. Property Editors.

Size: px

Start display at page:

Download "Property Editors and Customizers. COMP434 Software Design. Property Editors. Property Editors and. Property Editors."

Elvin McKinney
5 years ago
Views:

COMP434 Software Design and Customizers and Customizers A property editor allows the user to read and modify the value of one property A customizer provides a graphical user interface that allows the

1 COMP434 Software Design and Customizers and Customizers A property editor allows the user to read and modify the value of one property A customizer provides a graphical user interface that allows the user to edit multiple properties Useful for components that have complex functions Treats the component as a whole (can enforce dependencies between fields) 1 Software Design 2 A property may be represented on the Properties window in one of three ways: Its value can be displayed in a text field It can be shown as a choice element Useful for properties that are limited to a set of fixed values An image representing the property value can be painted into a small rectangle on the Properties window Eg the foreground/background Color properties of components Support for property editors: java.beans.propertyeditor Interface implemented by property editors java.beans.propertyeditorsupport No-op implementation of PropertyEditor Provides a firepropertychange() method to send a property change event to all registered listeners Software Design 3 Software Design 4 Methods in the PropertyEditor interface: addpropertychangelistener(propertychangelistener pcl) removepropertychangelistener(propertychangelistener pcl) String getastext() Returns a text representation of the property Void setastext(string str) throws IllegalArgumentException Uses str to set the property. An IllegalArgumentException is thrown if str is not formatted correctly or the property can t be set using a String Component getcustomeditor() Returns a reference to a custom property editor, or null if there is no custom editor boolean supportscustomeditor() String getjavainitializationstring() Returns a String that is a fragment of Java source code that can be used to initialize a variable with the value of a property Methods in the PropertyEditor interface (cont): String [] gettags() Return an array of strings that are the set of allowed values for this property Object getvalue() Return an Object that contains the value of this property void setvalue(object obj) Uses obj to set the value of this property boolean ispaintable() Returns true if the paintvalue() method can be used for this property void paintvalue(graphics g, Rectangle r) Paints a representation of this property in the Rectangle r on Graphics g Software Design 6 1

2 Representing properties as text fields Example code: PointViewer - a Bean that displays a square in which a point is positioned PointEditor - defines how the x and y coordinates of this point are represented (this is the property editor) PointViewerBeanInfo - associates PointEditor and PointViewer Software Design 7 package point; public class PointViewer extends JPanel { private Point point; public PointViewer() { point = new Point(0, 0); Dimension d = new Dimension(200, 200); setminimumsize(d); setpreferredsize(d); setmaximumsize(d); public Point getpoint() { return point; public void setpoint(point point) { this.point = point; // remaining code omitted package point; public class PointEditor extends PropertyEditorSupport { public String getastext() { Point point = (Point)getValue(); return "" + point.x + "," + point.y; public void setastext(string text) throws IllegalArgumentException { int index = text.indexof(","); String sx = (index == -1)? text : text.substring(0, index); String sy = (index == -1)? "0" : text.substring(index + 1); int x = Integer.parseInt(sx.trim()); int y = Integer.parseInt(sy.trim()); setvalue(new Point(x, y)); catch(exception ex) { throw new IllegalArgumentException(); package point; public class PointViewerBeanInfo extends SimpleBeanInfo { public PropertyDescriptor[] getpropertydescriptors() { PropertyDescriptor p1; p1 = new PropertyDescriptor("point", PointViewer.class); p1.setpropertyeditorclass(pointeditor.class); PropertyDescriptor pds[] = { p1 ; return pds; catch(exception ex) { ex.printstacktrace(); Representing properties as choices Example code IceCream - is a Bean that displays a square filled with the colour of the selected flavour (vanilla, chocolate, strawberry or pistachio) FlavourEditor - provides a set of choices from which the user can select one IceCreamBeanInfo - associates FlavourEditor and IceCream Software Design 12 2

3 package icecream; public class IceCream extends JPanel { private static Hashtable flavourtocolor; static { flavourtocolor = new Hashtable(); flavourtocolor.put("vanilla", new Color(255, 255, 255)); flavourtocolor.put("chocolate", new Color(119, 66, 8)); flavourtocolor.put("strawberry", new Color(236, 112, 132)); flavourtocolor.put("pistachio", new Color(113, 249, 158)); private String flavour; // the flavour property // Constructor omitted (see source code) public void paintcomponent(graphics g) { super.paintcomponent(g); Color color = (Color)flavourToColor.get(flavour); g.setcolor(color); Dimension d = getsize(); g.fillrect(0, 0, d.width 1, d.height 1); // end IceCream public String getflavour() { return flavour; public void setflavour(string flavour) { this.flavour = flavour; package icecream; public class FlavourEditor extends PropertyEditorSupport { public String[] gettags() { String flavours[] = { "Vanilla", "Chocolate", "Strawberry", "Pistachio" ; return flavours; //end FlavourEditor package icecream; public class IceCreamBeanInfo extends SimpleBeanInfo { public PropertyDescriptor[] getpropertydescriptors() { PropertyDescriptor p1; p1 = new PropertyDescriptor("flavour", IceCream.class); p1.setpropertyeditorclass(flavoureditor.class); PropertyDescriptor pds[] = { p1 ; return pds; catch(exception ex) { ex.printstacktrace(); // end IceCreamBeanInfo public class IceCream2 extends JPanel { private static Hashtable flavourtocolor; public static int VANILLA = 0; public static int CHOCOLATE = 1; public static int STRAWBERRY = 2; public static int PISTACHIO = 3; static { flavourtocolor = new Hashtable(); flavourtocolor.put(new Integer(VANILLA), new Color(255, 255, 25 flavourtocolor.put(new Integer(CHOCOLATE), new Color(119, 66, 8 flavourtocolor.put(new Integer(STRAWBERRY), new Color(236, 112, flavourtocolor.put(new Integer(PISTACHIO), new Color(113, 249, private int flavour; public int getflavour() { return flavour; public void setflavour(int flavour) { this.flavour = flavour; public class FlavourEditor2 extends PropertyEditorSupport { public String getastext() { Integer val = (Integer) getvalue(); switch (val.intvalue()) { case 0: return "Vanilla"; case 1: return "Chocolate"; case 2: return "Strawberry"; case 3: return "Pistachio"; return "Vanilla"; public void setastext(string text) { if (text.equals("vanilla")) { setvalue(new Integer(IceCream2.VANILLA)); else if (text.equals("chocolate")) { setvalue(new Integer(IceCream2.CHOCOLATE)); else if (text.equals("strawberry")) { setvalue(new Integer(IceCream2.STRAWBERRY)); else { setvalue(new Integer(IceCream2.PISTACHIO)); 3

4 public String[] gettags() { String flavours[] = { "Vanilla", "Chocolate", "Strawberry", "Pistachio" ; return flavours; // end FlavourEditor2 Custom property editors Example code: MultiLineLabel - is a Bean that renders a textual label over multiple lines Label property is a String where the characters or \n can be used to delimit lines MultiLineLabel2 - is the same as above but has a custom property editor for the label text LabelEditor - the custom property editor for MultiLineLabel2 Software Design 20 package label; public class MultiLineLabel extends JPanel { private String label = "Your label goes here!"; private int numlines; private String [] lines; private int [] linewidths; private int maxwidth; private boolean measured = false; private int lineheight; private static int MARGIN = 10; public MultiLineLabel() { newlabel(); private synchronized void newlabel() { StringTokenizer st = new StringTokenizer(label, " \n"); numlines = st.counttokens(); lines = new String [numlines]; linewidths = new int [numlines]; for (int i = 0; i < numlines; i++) { lines[i] = st.nexttoken(); public String getlabel() { return label; public void setlabel(string label) { this.label = label; newlabel(); measured = false; getparent().invalidate(); // force container to refresh getparent().dolayout(); public Dimension getpreferredsize() { if (!measured) { measure(); return new Dimension(maxWidth + (2 * MARGIN), (numlines * lineheight) + (2 * MARGIN)); public Dimension getminimumsize() { return getpreferredsize(); private synchronized void measure() { Graphics gx = getgraphics(); FontMetrics fm = gx.getfontmetrics(); lineheight = fm.getheight(); maxwidth = 0; for (int i = 0; i < numlines; i++) { linewidths[i] = fm.stringwidth(lines[i]); if (linewidths[i] > maxwidth) { maxwidth = linewidths[i]; measured = true; public void paintcomponent(graphics gx) { super.paintcomponent(gx); Dimension size = getsize(); if (!measured) { measure(); int x,y; y = MARGIN + (size.height numlines * lineheight)/2; for (int i = 0; i < numlines; i++, y += lineheight ) { x = (size.width linewidths[i])/2; gx.drawstring(lines[i], x, y); // end MultiLineLabel 4

5 package label; import java.awt.event.*; import javax.swing.jtextarea; import javax.swing.jscrollpane; import javax.swing.jbutton; public class LabelEditor extends JPanel implements PropertyEditor { private PropertyChangeSupport support = new PropertyChangeSupport(this); private String labelstring; private JTextArea ta = new JTextArea(5,20); public LabelEditor() { setlayout(new BorderLayout()); JScrollPane js = new JScrollPane(ta); add(js, BorderLayout.CENTER); JButton update = new JButton("Update Label"); add(update, BorderLayout.SOUTH); update.addactionlistener(new ActionListener() { public void actionperformed(actionevent e) { String old = labelstring; labelstring = ta.gettext(); support.firepropertychange("label", old, labelstring); ); public void setvalue(object o) { String old = labelstring; labelstring = ((String)o).replace(' ','\n'); ta.settext(labelstring); support.firepropertychange("label", old, labelstring); public Object getvalue() { return labelstring; public boolean ispaintable() { return true; public void paintvalue(graphics g, Rectangle r) { FontMetrics fm = g.getfontmetrics(); int verticalpad = (r.height fm.getheight()) / 2; g.drawstring("<click to edit>", 2, fm.getheight() + verticalpad); public boolean supportscustomeditor() { return true; public Component getcustomeditor() { return this; public String getjavainitializationstring() { public String getastext() { public void setastext(string s) throws IllegalArgumentException { throw new IllegalArgumentException(s); public String [] gettags() { public void addpropertychangelistener(propertychangelistener pcl) { support.addpropertychangelistener(pcl); public void removepropertychangelistener(propertychangelistener pcl) { support.removepropertychangelistener(pcl); // end LabelEditor package label; public class MultiLineLabel2BeanInfo extends SimpleBeanInfo { public PropertyDescriptor [] getpropertydescriptors() { PropertyDescriptor p1 = new PropertyDescriptor("label", MultiLineLabel2.class); p1.setpropertyeditorclass(labeleditor.class); PropertyDescriptor p2 = new PropertyDescriptor("background", MultiLineLabel2.class); PropertyDescriptor [] pds = {p1, p2; return pds; catch (Exception ex) { 5

6 Customizers Customizers A Bean developer may want to provide some way for the user to customize its properties other than by setting them one at a time Customizers allow the user to read and write several properties It can highlight dependencies between properties Could guide the user step by step (ie wizard style) through the process of configuring a complex Bean The Customizer interface is defined in the java.beans package Defines three methods: void addpropertychangelistener(propertychangelistener pcl) void removepropertychangelistener(propertychangeli pcl) void setobject(object bean) Called by the builder tool to give the customizer a reference to the Bean whose properties are to be modified Software Design 31 Software Design 32 Example code: Customizers Harmonics - a bean that displays a waveform that is calculated by summing together several different sine waves HarmonicsCustomizer - a graphical user interface that allows the user to select which sine waves to add together HarmonicsBeanInfo - associates HarmonicsCustomizer and Harmonics Software Design 33 package harmonics; public class Harmonics extends JPanel { public final static int NFREQUENCIES = 20; private BitSet frequencies; public Harmonics() { frequencies = new BitSet(NFREQUENCIES); Dimension d = new Dimension(301, 150); setminimumsize(d); setpreferredsize(d); setmaximumsize(d); public BitSet getfrequencies() { return frequencies; public void setfrequencies(bitset frequencies) { this.frequencies = frequencies; // see source code for the rest of this class package harmonics; import java.awt.event.*; import javax.swing.jlabel; import javax.swing.jlist; import javax.swing.defaultlistmodel; import javax.swing.listselectionmodel; import javax.swing.event.listdatalistener; import javax.swing.event.listdataevent; public class HarmonicsCustomizer extends JPanel implements Customizer { private PropertyChangeSupport pcsupport = new PropertyChangeSupport(this); private Harmonics harmonics; private JList list; private JPanel p; public HarmonicsCustomizer() { setlayout(new BorderLayout()); JLabel label = new JLabel("Select Harmonics:", JLabel.CENTER); add(label, BorderLayout.NORTH); DefaultListModel dl = new DefaultListModel(); for(int i = 1; i <= Harmonics.NFREQUENCIES; i++) { String s = "(1/" + i + ")(sin" + i + "x)"; dl.addelement(s); list = new JList(dl); list.setselectionmode(listselectionmodel. MULTIPLE_INTERVAL_SELECTION); list.addmouselistener(new MouseAdapter() { public void mouseclicked(mouseevent e) { BitSet frequencies = new BitSet(Harmonics.NFREQUENCIES); for(int i = 0; i < Harmonics.NFREQUENCIES; i++) { if(list.isselectedindex(i)) { frequencies.set(i); harmonics.setfrequencies(frequencies); ); // some code left out see source 6

7 public void setobject(object object) { // Save reference to the Harmonics object harmonics = (Harmonics)object; // Get data from the harmonics object BitSet frequencies = harmonics.getfrequencies(); for(int i = 0; i < Harmonics.NFREQUENCIES; i++) { if(frequencies.get(i)) { list.addselectioninterval(i,i); package harmonics; public class HarmonicsBeanInfo extends SimpleBeanInfo { public BeanDescriptor getbeandescriptor() { return new BeanDescriptor(Harmonics.class, HarmonicsCustomizer.class); // see source for remaining code // end HarmonicsCustomizer 7

Bean Communication. COMP434B Software Design. Bean Communication. Bean Communication. Bean Communication. Bean Communication

Bean Communication. COMP434B Software Design. Bean Communication. Bean Communication. Bean Communication. Bean Communication COMP434B Software Design JavaBeans: Events and Reflection Events are the primary mechanism by which Java components interact with each other One Bean generates an event and one or more other Beans receive