Java 1.2 How-To/JavaHowTo.iso/3rdParty/jbuilder/unsupported/JDK1.2beta3/SOURCE/SRC.ZIP/java/awt/swing/UIManager.java

Java Source | 1998-03-20 | 22.1 KB | 661 lines

/*
 * @(#)UIManager.java    1.54 98/02/23
 *
 * Copyright (c) 1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not disclose
 * such Confidential Information and shall use it only in accordance with the
 * terms of the license agreement you entered into with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
 * OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR
 * ITS DERIVATIVES.
 *
 */
package java.awt.swing;

import java.awt.Container;
import java.awt.Window;
import java.awt.Font;
import java.awt.Color;

import java.awt.swing.plaf.ComponentUI;
import java.awt.swing.border.Border;

import java.beans.PropertyChangeSupport;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.io.File;
import java.io.FileInputStream;
import java.io.BufferedInputStream;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.Vector;


/**
 * This class keeps track of the current look and feel and its
 * defaults.
 * <p>
 * We manage three levels of defaults: user defaults, look
 * and feel defaults, system defaults.  A call to UIManager.get()
 * checks all three levels in order and returns the first non-null
 * value for a key, if any.  A call to UIManager.put() just
 * affects the user defaults.  Note that a call to
 * setLookAndFeel() doesn't affect the user defaults, it just
 * replaces the middle defaults "level".
 * <p>
 * Warning: serialized objects of this class will not be compatible with
 * future swing releases.  The current serialization support is appropriate
 * for short term storage or RMI between Swing1.0 applications.  It will
 * not be possible to load serialized Swing1.0 objects with future releases
 * of Swing.  The JDK1.2 release of Swing will be the compatibility
 * baseline for the serialized form of Swing objects.
 *
 * @version 1.54 02/23/98
 * @author Thomas Ball
 * @author Hans Muller
 */
public class UIManager implements Serializable
{
    /**
     * This class defines the state managed by the UIManager.  For
     * Swing applications the fields in this class could just as well
     * be static members of UIManager however we give them "AppContext"
     * scope instead so that applets (and potentially multiple lightweight
     * applications running in a single VM) have their own state. For
     * example an applet can it's look and feel, see setLookAndFeel().
     * Doing so has no affect on other applets (or the browser).
     */
    private static class LAFState
    {
    private UIDefaults[] tables = new UIDefaults[2];

    boolean initialized = false;
    MultiUIDefaults multiUIDefaults = new MultiUIDefaults(tables);
    LookAndFeel lookAndFeel;
    LookAndFeel multiLookAndFeel = null;
    Vector auxLookAndFeels = null;
    PropertyChangeSupport changeSupport = new PropertyChangeSupport(UIManager.class);

    UIDefaults getLookAndFeelDefaults() { return tables[0]; }
    void setLookAndFeelDefaults(UIDefaults x) { tables[0] = x; }

    UIDefaults getSystemDefaults() { return tables[1]; }
    void setSystemDefaults(UIDefaults x) { tables[1] = x; }
    }


    /**
     * The AppContext key for our one LAFState instance.
     */
    private static final Object lafStateACKey = new StringBuffer("LookAndFeel State");


    /**
     * Return the LAFState object, lazily create one if neccessary.  All access
     * to the LAFState fields is done via this method, e.g.:
     * <pre>
     *     getLAFState().initialized = true;
     * </pre>
     */
    private static LAFState getLAFState() {
    LAFState rv = (LAFState)SwingUtilities.appContextGet(lafStateACKey);
    if (rv != null) {
        return rv;
    }
    synchronized(UIManager.class) {
        rv = (LAFState)SwingUtilities.appContextGet(lafStateACKey);
        if (rv != null) {
        return rv;
        }
        SwingUtilities.appContextPut(lafStateACKey, (rv = new LAFState()));
        return rv;
    }
    }


    /* Keys used for the properties file in <java.home>/lib/swing.properties.
     * See loadUserProperties(), initialize().
     */

    private static final String defaultLAFKey = "swing.defaultlaf";
    private static final String auxiliaryLAFsKey = "swing.auxiliarylaf";
    private static final String multiplexingLAFKey = "swing.plaf.multiplexinglaf";
    private static final String installedLAFsKey = "swing.installedlafs";

    /**
     * Return a swing.properties file key for the attribute of specified
     * look and feel.  The attr is either "name" or "class", a typical
     * key would be: "swing.installedlaf.windows.name"
     */
    private static String makeInstalledLAFKey(String laf, String attr) {
        return "swing.installedlaf." + laf + "." + attr;
    }

    /**
     * The filename for swing.properties is a path like this (Unix version):
     * <java.home>/lib/swing.properties.  This method returns a bogus
     * filename if java.home isn't defined.
     */
    private static String makeSwingPropertiesFilename() {
        String sep = File.separator;
        String homeDir = System.getProperty("java.home", "<java.home undefined>");
        return homeDir + sep + "lib" + sep + "swing.properties";
    }


    /**
     * Provide a little information about an installed LookAndFeel
     * for the sake of configuring a menu or for initial application
     * set up.
     *
     * @see #getInstalledLookAndFeels
     * @see LookAndFeel
     */
    public static class LookAndFeelInfo {
        private String name;
        private String className;

        public LookAndFeelInfo(String name, String className) {
            this.name = name;
            this.className = className;
        }

        /**
         * @return a name suitable for a menu or other presentation
         * @see LookAndFeel#getName
         */
        public String getName() {
            return name;
        }

        /**
         * @return the name of the class that implements this LookAndFeel.
         * @see LookAndFeel
         */
        public String getClassName() {
            return className;
        }

        public String toString() {
            return getClass().getName() + "[" + getName() + " " + getClassName() + "]";
        }
    }


    /**
     * The default value of installedLAFS is used when no swing.properties
     * file is available or if the file doesn't contain a "swing.installedlafs"
     * property.
     *
     * @see #initializeInstalledLAFs
     */
    private static LookAndFeelInfo[] installedLAFs = {
        new LookAndFeelInfo("Metal", "java.awt.swing.plaf.metal.MetalLookAndFeel"),
        new LookAndFeelInfo("CDE/Motif", "java.awt.swing.plaf.motif.MotifLookAndFeel"),
        new LookAndFeelInfo("Windows", "java.awt.swing.plaf.windows.WindowsLookAndFeel")
    };


    /**
     * Return an array of objects that provide some information about the
     * LookAndFeel implementations that have been installed with this
     * java development kit.  The LookAndFeel info objects can be used
     * by an application to construct a menu of look and feel options for
     * the user or to set the look and feel at start up time.  Note that
     * we do not return the LookAndFeel classes themselves here to avoid the
     * cost of unnecessarily loading them.
     * <p>
     * Given a LookAndFeelInfo object one can set the current look and feel
     * like this:
     * <pre>
     * UIManager.setLookAndFeel(info.getClassName());
     * </pre>
     *
     * @see #setLookAndFeel
     */
    public static LookAndFeelInfo[] getInstalledLookAndFeels() {
        maybeInitialize();
        LookAndFeelInfo[] ilafs = installedLAFs;
        LookAndFeelInfo[] rv = new LookAndFeelInfo[ilafs.length];
        System.arraycopy(ilafs, 0, rv, 0, ilafs.length);
        return rv;
    }


    /**
     * Replaces the current array of installed LookAndFeelInfos.
     *
     * @see #getInstalledLookAndFeels
     */
    public static void setInstalledLookAndFeels(LookAndFeelInfo[] infos)
        throws SecurityException
    {
        LookAndFeelInfo[] newInfos = new LookAndFeelInfo[infos.length];
        System.arraycopy(infos, 0, newInfos, 0, infos.length);
        installedLAFs = newInfos;
    }


    /**
     * Adds the specified look and feel to the current array and
     * then calls setInstalledLookAndFeels.
     *
     * @see #setInstalledLookAndFeels
     */
    public static void installLookAndFeel(LookAndFeelInfo info) {
        LookAndFeelInfo[] infos = getInstalledLookAndFeels();
        LookAndFeelInfo[] newInfos = new LookAndFeelInfo[infos.length + 1];
        System.arraycopy(infos, 0, newInfos, 0, infos.length);
        newInfos[infos.length] = info;
        setInstalledLookAndFeels(newInfos);
    }


    public static void installLookAndFeel(String name, String className) {
        installLookAndFeel(new LookAndFeelInfo(name, className));
    }


    /**
     * Returns The current default look and feel, or null.
     *
     * @return The current default look and feel, or null.
     * @see #setLookAndFeel
     */
    public static LookAndFeel getLookAndFeel() {
        maybeInitialize();
        return getLAFState().lookAndFeel;
    }


    /**
     * Set the current default look and feel.
     * <p>
     * This is a JavaBeans bound property.
     *
     * @exception UnsupportedLookAndFeelException If <code>lnf.isSupportedLookAndFeel()</code> is false.
     * @see #getLookAndFeel
     */
    public static void setLookAndFeel(LookAndFeel newLookAndFeel)
        throws UnsupportedLookAndFeelException
    {
        if ((newLookAndFeel != null) && !newLookAndFeel.isSupportedLookAndFeel()) {
            String s = newLookAndFeel.toString() + " not supported on this platform";
            throw new UnsupportedLookAndFeelException(s);
        }

    LookAndFeel oldLookAndFeel = getLAFState().lookAndFeel;
        if (oldLookAndFeel != null) {
            oldLookAndFeel.uninitialize();
        }

    getLAFState().lookAndFeel = newLookAndFeel;
        if (newLookAndFeel != null) {
            newLookAndFeel.initialize();
        getLAFState().setLookAndFeelDefaults(newLookAndFeel.getDefaults());
        }
        else {
        getLAFState().setLookAndFeelDefaults(null);
        }

        getLAFState().changeSupport.firePropertyChange("lookAndFeel", oldLookAndFeel, newLookAndFeel);
    }


    /**
     * @exception ClassNotFoundException If the LookAndFeel class could not be found.
     * @exception InstantiationException If a new instance of the class couldn't be creatd.
     * @exception IllegalAccessException If the class or initializer isn't accessible.
     * @exception UnsupportedLookAndFeelException If <code>lnf.isSupportedLookAndFeel()</code> is false.
     */
    public static void setLookAndFeel(String className)
        throws ClassNotFoundException,
               InstantiationException,
               IllegalAccessException,
               UnsupportedLookAndFeelException
    {
        Class lnfClass = Class.forName(className);
        setLookAndFeel((LookAndFeel)(lnfClass.newInstance()));
    }


    /**
     * Returns the name of the LookAndFeel class that implements
     * the native systems look and feel if there is one,
     * otherwise the name of the default cross platform LookAndFeel
     * class.
     *
     * @see #setLookAndFeel()
     * @see #getCrossPlatformLookAndFeelClassName
     */
    public static String getSystemLookAndFeelClassName() {
        String osName = System.getProperty("os.name");
        if (osName != null) {
        if (osName.indexOf("Windows") != -1) {
        return "java.awt.swing.plaf.windows.WindowsLookAndFeel";
        }
        else if (osName.indexOf("Solaris") != -1) {
        return "java.awt.swing.plaf.motif.MotifLookAndFeel";
        }
        }
    return getCrossPlatformLookAndFeelClassName();
    }


    /**
     * Returns the name of the LookAndFeel class that implements
     * the default cross platform look and feel, i.e. the "metal"
     * look and feel.
     *
     * @return "java.awt.swing.plaf.metal.MetalLookAndFeel"
     * @see #setLookAndFeel()
     * @see #getSystemLookAndFeelClassName
     */
    public static String getCrossPlatformLookAndFeelClassName() {
    return "java.awt.swing.plaf.metal.MetalLookAndFeel";
    }


    public static UIDefaults getDefaults() {
        maybeInitialize();
    return getLAFState().multiUIDefaults;
    }

    public static Font getFont(Object key) {
        return getDefaults().getFont(key);
    }

    public static Color getColor(Object key) {
        return getDefaults().getColor(key);
    }

    public static Icon getIcon(Object key) {
        return getDefaults().getIcon(key);
    }

    public static Border getBorder(Object key) {
        return getDefaults().getBorder(key);
    }

    public static String getString(Object key) {
        return getDefaults().getString(key);
    }

    public static Object get(Object key) {
        return getDefaults().get(key);
    }

    public static Object put(Object key, Object value) {
        return getDefaults().put(key, value);
    }

    public static ComponentUI getUI(JComponent target) {
        maybeInitialize();
        ComponentUI ui = null;
        LookAndFeel multiLAF = getLAFState().multiLookAndFeel;
        if (multiLAF != null) {
        // This can return null if the multiplexing look and feel
        // doesn't support a particular UI.
        ui = multiLAF.getDefaults().getUI(target);
        }
        if (ui == null) {
            ui = getDefaults().getUI(target);
        }
        return ui;
    }


    public static UIDefaults getLookAndFeelDefaults() {
        maybeInitialize();
    return getLAFState().getLookAndFeelDefaults();
    }


    /**
     * Return the list of auxiliary look and feels (can be null).  The
     * auxiliary look and feels tell the multiplexing look and feel what
     * other LookAndFeel classes for a component instance are to be used
     * in addition to the default LookAndFeel class when creating a
     * multiplexing UI.
     * <p>Note these are not the same as the installed look and feels.
     * @see #getInstalledLookAndFeels
     */
    static public LookAndFeel[] getAuxiliaryLookAndFeels()
    {
        maybeInitialize();

    Vector v = getLAFState().auxLookAndFeels;
    if ((v == null) || (v.size() == 0)) {
        return null;
    }
    else {
        LookAndFeel[] rv = new LookAndFeel[v.size()];
        for (int i = 0; i < rv.length; i++) {
        rv[i] = (LookAndFeel)v.elementAt(i);
        }
        return rv;
    }
    }


    /**
     * Add a PropertyChangeListener to the listener list.
     * The listener is registered for all properties.
     *
     * @param listener  The PropertyChangeListener to be added
     * @see java.beans.PropertyChangeSupport
     */
    public synchronized static void addPropertyChangeListener(PropertyChangeListener listener)
    {
        getLAFState().changeSupport.addPropertyChangeListener(listener);
    }


    /**
     * Remove a PropertyChangeListener from the listener list.
     * This removes a PropertyChangeListener that was registered
     * for all properties.
     *
     * @param listener  The PropertyChangeListener to be removed
     * @see java.beans.PropertyChangeSupport
     */
    public synchronized static void removePropertyChangeListener(PropertyChangeListener listener)
    {
    getLAFState().changeSupport.removePropertyChangeListener(listener);
    }


    private static Properties loadSwingProperties()
    {
        Properties properties = new Properties();

        if (UIManager.class.getClassLoader() == null) {
            String sep = File.separator;
            try {
                File propertiesFile = new File(makeSwingPropertiesFilename());
                BufferedInputStream ins = new BufferedInputStream(
                    new FileInputStream(propertiesFile));
                properties.load(ins);
                ins.close();
            }
            catch (Exception e) {
                properties.clear();
            }
        }

        return properties;
    }


    /**
     * If a swing.properties file exist and it has a swing.installedlafs property
     * then initialize the installedLAFs field.
     *
     * @see #getInstalledLookAndFeels
     */
    private static void initializeInstalledLAFs(Properties swingProps)
    {
        String ilafsString = swingProps.getProperty(installedLAFsKey);
        if (ilafsString == null) {
            return;
        }

        /* Create a vector that contains the value of the swing.installedlafs
         * property.  For example given "swing.installedlafs=motif,windows"
         * lafs = {"motif", "windows"}.
         */
        Vector lafs = new Vector();
        StringTokenizer st = new StringTokenizer(ilafsString, ",", false);
        while (st.hasMoreTokens()) {
            lafs.addElement(st.nextToken());
        }

        /* Look up the name and class for each name in the "swing.installedlafs"
         * list.  If they both exist then add a LookAndFeelInfo to
         * the installedLafs array.
         */
        Vector ilafs = new Vector(lafs.size());
        for(int i = 0; i < lafs.size(); i++) {
            String laf = (String)lafs.elementAt(i);
            String name = swingProps.getProperty(makeInstalledLAFKey(laf, "name"), laf);
            String cls = swingProps.getProperty(makeInstalledLAFKey(laf, "class"));
            if (cls != null) {
                ilafs.addElement(new LookAndFeelInfo(name, cls));
            }
        }

        installedLAFs = new LookAndFeelInfo[ilafs.size()];
        for(int i = 0; i < ilafs.size(); i++) {
            installedLAFs[i] = (LookAndFeelInfo)(ilafs.elementAt(i));
        }
    }


    /**
     * If the user has specified a default look and feel, use that.
     * Otherwise use the look and feel that's native to this platform.
     * If this code is called after the application has expclicitly
     * set it's look and feel, do nothing.
     *
     * @see #maybeInitialize
     */
    private static void initializeDefaultLAF(Properties swingProps)
    {
        if (getLAFState().lookAndFeel != null) {
            return;
        }

        String metalLnf = getCrossPlatformLookAndFeelClassName();
        String lnfDefault = metalLnf;

        String lnfName = "<undefined>" ;
        try {
            lnfName = swingProps.getProperty(defaultLAFKey, lnfDefault);
            Class lnfClass = Class.forName(lnfName);
            setLookAndFeel((LookAndFeel)(lnfClass.newInstance()));
        } catch (Exception e) {
            try {
                lnfName = swingProps.getProperty(defaultLAFKey, metalLnf);
                Class lnfClass = Class.forName(lnfName);
                setLookAndFeel((LookAndFeel)(lnfClass.newInstance()));
            } catch (Exception e2) {
                throw new Error("can't load " + lnfName);
            }
        }
    }


    private static void initializeAuxiliaryLAFs(Properties swingProps)
    {
        String auxLookAndFeelNames = swingProps.getProperty(auxiliaryLAFsKey);
        if (auxLookAndFeelNames == null) {
            return;
        }

        Vector auxLookAndFeels = new Vector();

        StringTokenizer p = new StringTokenizer(auxLookAndFeelNames,",");
        String factoryName;

        /* Try to load each LookAndFeel subclass in the list.
         */

        while (p.hasMoreTokens()) {
            String className = p.nextToken();
            try {
                Class lnfClass = Class.forName(className);
                auxLookAndFeels.addElement(lnfClass.newInstance());
            }
            catch (Exception e) {
                System.err.println("UIManager: failed loading auxiliary look and feel " + className);
            }
        }

        /* If there were problems and no auxiliary look and feels were
         * loaded, make sure we reset auxLookAndFeels to null.
         * Otherwise, we are going to use the MultiLookAndFeel to get
         * all component UI's, so we need to load it now.
         */

        if (auxLookAndFeels.size() == 0) {
            auxLookAndFeels = null;
        }
        else {
            String defaultName = "java.awt.swing.plaf.multi.MultiLookAndFeel";
            String className = swingProps.getProperty(multiplexingLAFKey, defaultName);
            try {
                Class lnfClass = Class.forName(className);
                getLAFState().multiLookAndFeel = (LookAndFeel)lnfClass.newInstance();
            }
            catch (Exception exc) {
                System.err.println("UIManager: failed loading " + className);
                auxLookAndFeels = null;
            }
        }

    getLAFState().auxLookAndFeels = auxLookAndFeels;
    }


    private static void initializeSystemDefaults(Properties swingProps)
    {
        Object defaults[] = {
            "FocusManagerClassName", "java.awt.swing.DefaultFocusManager"
        };
        getLAFState().setSystemDefaults(new UIDefaults(defaults));
    }


    private static void initialize()
    {
        Properties swingProps = loadSwingProperties();
        initializeSystemDefaults(swingProps);
        initializeDefaultLAF(swingProps);
        initializeAuxiliaryLAFs(swingProps);
        initializeInstalledLAFs(swingProps);
    }


    synchronized private static void maybeInitialize() {
    if (!getLAFState().initialized) {
        initialize();
        getLAFState().initialized = true;
    }
    }
}