InstantSearchExample.java

package prototypes;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

@SuppressWarnings("serial")
public class InstantSearchExample extends JFrame {

	private JTextArea console;
	private JTextField input;
	
	private Thread pre;
	
	private Random rand = new Random(2344);

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		InstantSearchExample test = new InstantSearchExample();
		test.pack();
		test.setVisible(true);
	}
	
	public InstantSearchExample() {
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		initUI();
	}

	private void initUI() {
		setLayout(new GridBagLayout());

		input = new JTextField();
		input.getDocument().addDocumentListener(new DocumentListener() {
			@Override
			public void removeUpdate(DocumentEvent e) {
				startSearchJob();
			}

			@Override
			public void insertUpdate(DocumentEvent e) {
				startSearchJob();
			}
			
			@Override
			public void changedUpdate(DocumentEvent e) {
				startSearchJob();
			}
		});
		
		console = new JTextArea();
		console.setEditable(false);
		JScrollPane scroller = new JScrollPane(console, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
		scroller.setPreferredSize(new Dimension(320, 400));
		
		GridBagConstraints cons = new GridBagConstraints();
		cons.fill = GridBagConstraints.HORIZONTAL;
		cons.weightx = 1.0;
		cons.gridx = 0;
		cons.gridy = 0;
		add(input, cons);
		cons.gridx = 0;
		cons.gridy = 1;
		cons.fill = GridBagConstraints.BOTH;
		cons.weighty = 1.0;
		add(scroller, cons);
	}
	
	private void startSearchJob() {
		new Thread() {
			@Override
			public void run() {
				pre = this;
				String text = input.getText();
				try {
					Thread.sleep(600);
				} catch (Exception e) {
				} finally {
					if (pre == this) {
						int cost = search(text);
						if (pre == this) {
							console.append(String.format("Cost: %1dms, %2s\r\n", cost, text));
						} else {
							console.append(String.format("Cost: %1dms, %2s dropped\r\n", cost, text));
						}
					}
				}
			}
			
		}.start();
	}
	
	private int search(String text) {
		int cost = rand.nextInt(4000);
		try {
			Thread.sleep(cost);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		return cost;
	}

}