WindowsUtils.java

package main.utils;

import java.util.LinkedList;
import java.util.List;

import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.User32;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.ptr.IntByReference;

/**
 * Utility methods to handle windows outside of the man program.
 *
 * @author Maxime PIA
 */
public class WindowsUtils {

	/*private static interface User32 extends StdCallLibrary {
		User32 INSTANCE = (User32) Native.loadLibrary("user32", User32.class);
		int WND_HIDE = 0;
		int WND_SHOW = 0;

		interface WNDENUMPROC extends StdCallCallback {
			boolean callback(HWND hWnd, HWND arg);
		}

		boolean EnumWindows(WNDENUMPROC lpEnumFunc, HWND userData);
		int GetWindowTextA(HWND hWnd, byte[] lpString, int nMaxCount);
		int GetWindowThreadProcessId(HWND hWnd,
			IntByReference lpdwProcessId);
		boolean IsWindowVisible(HWND hWnd);
		boolean ShowWindow(HWND hWnd, int nCmdShow);
	}*/

	private static User32 user32 = User32.INSTANCE;

	/**
	 * Finds all visible window threads.
	 *
	 * @return All visible window threads.
	 */
	public static List<HWND> findAll() {
		final List<HWND> windows = new LinkedList<>();
		user32.EnumWindows(new User32.WNDENUMPROC() {
			@Override
			public boolean callback(HWND hWnd, Pointer arg) {
				if (user32.IsWindowVisible(hWnd)) {
					windows.add(hWnd);
				}
				return true;
			}
		}, null);
		return windows;
	}

	/**
	 * Finds windows using the PID of their process among all visible windows.
	 *
	 * @param pid The PID of the process.
	 * @return The windows whose process has the given PID.
	 */
	public static List<HWND> findByPID(long pid) {
		return findByPID(pid, findAll());
	}

	/**
	 * Finds windows using the PID of their process.
	 *
	 * @param pid The PID of the process.
	 * @param windows A list of windows in which the search is performed.
	 * @return The windows whose process has the given PID.
	 */
	public static List<HWND> findByPID(long pid,
		List<HWND> windows) {

		final List<HWND> filteredWindows = new LinkedList<>();
		for (HWND window : windows) {
			IntByReference PIDRef = new IntByReference();
			user32.GetWindowThreadProcessId(window, PIDRef);
			if (PIDRef.getValue() == pid) {
				filteredWindows.add(window);
			}
		}
		return filteredWindows;
	}

	/**
	 * Finds windows by their title among all visible windows.
	 *
	 * @param title A string contained in the title of the windows.
	 * @return The windows having the given title.
	 */
	public static List<HWND> findByTitle(String title) {
		return findByTitle(title, findAll());
	}

	/**
	 * Finds windows by their title.
	 *
	 * @param title A string contained in the title of the windows.
	 * @param windows A list of windows in which the search is performed.
	 * @return The windows having the given title.
	 */
	public static List<HWND> findByTitle(String title,
		List<HWND> windows) {

		final List<HWND> filteredWindows = new LinkedList<>();
		for (HWND window : windows) {
			char[] windowText = new char[512];
			user32.GetWindowText(window, windowText, 512);
			String currentTitle = Native.toString(windowText).trim();
			if (!currentTitle.isEmpty() && currentTitle.contains(title)) {
				filteredWindows.add(window);
			}
		}
		return filteredWindows;
	}

	/**
	 * Sets the visibility of a window, including its icon in the taskbar.
	 *
	 * @param window The window.
	 * @param visible True to show the window, false to hide it.
	 */
	public static void setVisible(HWND window, boolean visible) {
		user32.ShowWindow(window, visible ? 1 : 0);
	}

}