First SWidgets example: Spinner

book/swidgets/java/.gitignore

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+*.class
+*.jar

book/swidgets/java/build.xml

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+<project default="compile">
+
+    <target name="clean">
+        <delete dir="swidgets/build"/>
+        <delete file="swidgets/swidgets.jar"/>
+        <delete>
+            <fileset dir="examples" includes="*.class"/>
+        </delete>
+    </target>
+
+    <target name="compile">
+        <subant buildpath="../../../java"/>
+        <mkdir dir="swidgets/build/src"/>
+        <javac debug="true" srcdir="swidgets/src" destdir="swidgets/build/src" source="1.8" target="1.8">
+            <classpath>
+                <pathelement path="../../../java/sodium/sodium.jar"/>
+            </classpath>
+        </javac>
+    </target>
+
+    <target name="jar" depends="compile">
+        <mkdir dir="swidgets/build/jar" />
+        <jar destfile="swidgets/swidgets.jar" basedir="swidgets/build/src">
+            <manifest>
+                <attribute name="Main-Class" value="oata.HelloWorld" />
+            </manifest>
+        </jar>
+    </target>
+
+    <target name="compile-examples" depends="jar">
+        <javac debug="true" srcdir="examples" destdir="examples" source="1.8" target="1.8">
+            <classpath>
+                <pathelement path="swidgets/swidgets.jar"/>
+                <pathelement path="../../../java/sodium/sodium.jar"/>
+            </classpath>
+        </javac>
+    </target>
+
+    <target name="example1" depends="compile-examples">
+        <java classname="Example1" fork="true">
+            <classpath>
+                <pathelement path="examples"/>
+                <pathelement path="swidgets/swidgets.jar"/>
+                <pathelement path="../../../java/sodium/sodium.jar"/>
+            </classpath>
+        </java>
+    </target>
+
+</project>

book/swidgets/java/examples/Example1.java

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+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import sodium.*;
+
+public class Example1 {
+    public static void main(String[] args) {
+        JFrame view = new JFrame("Example1") {
+            public Dimension getPreferredSize() {
+                return new Dimension(400, 160);
+            }
+        };
+        Transaction.runVoid(() -> {
+            view.setLayout(new FlowLayout());
+
+            SSpinner spnr = new SSpinner();
+            view.add(spnr);
+
+            view.addWindowListener(new WindowAdapter() {
+                public void windowClosing(WindowEvent e) {
+                    System.exit(0);
+                }
+            });
+            view.pack();
+        });
+        view.setVisible(true);
+    }
+}
+

book/swidgets/java/examples/SSpinner.java

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+import javax.swing.*;
+import java.awt.*;
+import swidgets.*;
+import sodium.*;
+
+public class SSpinner extends JComponent
+{
+    SSpinner()
+    {
+        StreamLoop<String> sSetText = new StreamLoop<>();
+        STextField textField = new STextField("0", sSetText, 5);
+        this.text = textField.text;
+        SButton up = new SButton("+");
+        SButton down = new SButton("-");
+
+        GridBagLayout gridbag = new GridBagLayout();
+        setLayout(gridbag);
+        GridBagConstraints c = new GridBagConstraints();
+        c.fill = GridBagConstraints.BOTH;
+        c.weightx = 1.0;
+        c.gridx = 0;
+        c.gridy = 0;
+        c.gridwidth = 1;
+        c.gridheight = 2;
+        gridbag.setConstraints(textField, c);
+        add(textField);
+        c.gridwidth = 1;
+        c.gridheight = 1;
+        c.gridx = 1;
+        c.gridy = 0;
+        gridbag.setConstraints(up, c);
+        add(up);
+        c.gridx = 1;
+        c.gridy = 1;
+        gridbag.setConstraints(down, c);
+        add(down);
+
+        Stream<Integer> sUpDelta = up.sClicked.map(u -> 1);
+        Stream<Integer> sDownDelta = down.sClicked.map(u -> -1);
+        Stream<Integer> sDelta = sUpDelta.merge(sDownDelta);
+        sSetText.loop(
+            sDelta.snapshot(
+                textField.text,
+                (delta, txt) -> {
+                    try {
+                        return Integer.toString(Integer.parseInt(txt) + delta);
+                    }
+                    catch (NumberFormatException e) {
+                        System.err.println("can't parse "+txt);
+                        return txt;
+                    }
+                }
+            )
+        );
+    }
+
+    public final Cell<String> text;
+}
+

book/swidgets/java/swidgets/src/swidgets/SButton.java

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+package swidgets;
+
+import sodium.*;
+import javax.swing.JButton;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class SButton extends JButton
+{
+    public SButton(String label)
+    {
+        super(label);
+        StreamSink<Unit> sClickedSink = new StreamSink<>();
+        this.sClicked = sClickedSink;
+        addActionListener(new ActionListener() {
+            public void actionPerformed(ActionEvent e) {
+                sClickedSink.send(Unit.UNIT);
+            }
+        });
+    }
+
+    public final Stream<Unit> sClicked;
+}

book/swidgets/java/swidgets/src/swidgets/STextField.java

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+package swidgets;
+
+import sodium.*;
+import javax.swing.event.DocumentEvent;
+import javax.swing.event.DocumentListener;
+import javax.swing.*;
+import javax.swing.SwingUtilities;
+import java.util.concurrent.ArrayBlockingQueue;
+
+public class STextField extends JTextField
+{
+    public STextField(String initText, Stream<String> sText, int width)
+    {
+        super(initText, width);
+
+        allow = sText.map(u -> 1).merge(sDecrement).accum(0, (d, b) -> b + d).map(b -> b == 0);
+
+        final StreamSink<String> sUserText = new StreamSink<String>();
+        this.text = sUserText.gate(allow).merge(sText).hold(initText);
+        DocumentListener dl = new DocumentListener() {
+            public void changedUpdate(DocumentEvent e) {
+                update();
+            }
+            public void removeUpdate(DocumentEvent e) {
+                update();
+            }
+            public void insertUpdate(DocumentEvent e) {
+                update();
+            }
+
+            public void update() {
+                sUserText.send(getText());
+            }
+        };
+
+        getDocument().addDocumentListener(dl);
+
+        l = sText.listen(text -> {
+            SwingUtilities.invokeLater(() -> {
+                setText(text);
+                sDecrement.send(-1);
+            });
+        });
+    }
+
+    private final StreamSink<Integer> sDecrement = new StreamSink<>();
+    private final Cell<Boolean> allow;
+    private final Listener l;
+    public final Cell<String> text;
+
+    public void removeNotify() {
+        l.unlisten();
+        super.removeNotify();
+    }
+}
+