/*

 * Copyright (c) 2002, 2008, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.swing.plaf.synth;

import java.util.Queue;

import java.util.concurrent.ConcurrentLinkedQueue;

import javax.swing.JComponent;

/**

 * An immutable transient object containing contextual information about

 * a <code>Region</code>. A <code>SynthContext</code> should only be

 * considered valid for the duration

 * of the method it is passed to. In other words you should not cache

 * a <code>SynthContext</code> that is passed to you and expect it to

 * remain valid.

 *

 * @since 1.5

 * @author Scott Violet

 */

public class SynthContext {

    private static final Queue<SynthContext> queue = new ConcurrentLinkedQueue<>();

    private JComponent component;

    private Region region;

    private SynthStyle style;

    private int state;

    static SynthContext getContext(JComponent c, SynthStyle style, int state) {

        return getContext(c, SynthLookAndFeel.getRegion(c), style, state);

    }

    static SynthContext getContext(JComponent component,

                                   Region region, SynthStyle style,

                                   int state) {

        SynthContext context = queue.poll();

        if (context == null) {

            context = new SynthContext();

        }

        context.reset(component, region, style, state);

        return context;

    }

    static void releaseContext(SynthContext context) {

        queue.offer(context);

    }

    SynthContext() {

    }

    /**

     * Creates a SynthContext with the specified values. This is meant

     * for subclasses and custom UI implementors. You very rarely need to

     * construct a SynthContext, though some methods will take one.

     *

     * @param component JComponent

     * @param region Identifies the portion of the JComponent

     * @param style Style associated with the component

     * @param state State of the component as defined in SynthConstants.

     * @throws NullPointerException if component, region of style is null.

     */

    public SynthContext(JComponent component, Region region, SynthStyle style,

                        int state) {

        if (component == null || region == null || style == null) {

            throw new NullPointerException(

                "You must supply a non-null component, region and style");

        }

        reset(component, region, style, state);

    }

    /**

     * Returns the hosting component containing the region.

     *

     * @return Hosting Component

     */

    public JComponent getComponent() {

        return component;

    }

    /**

     * Returns the Region identifying this state.

     *

     * @return Region of the hosting component

     */

    public Region getRegion() {

        return region;

    }

    /**

     * A convenience method for <code>getRegion().isSubregion()</code>.

     */

    boolean isSubregion() {

        return getRegion().isSubregion();

    }

    void setStyle(SynthStyle style) {

        this.style = style;

    }

    /**

     * Returns the style associated with this Region.

     *

     * @return SynthStyle associated with the region.

     */

    public SynthStyle getStyle() {

        return style;

    }

    void setComponentState(int state) {

        this.state = state;

    }

    /**

     * Returns the state of the widget, which is a bitmask of the

     * values defined in <code>SynthConstants</code>. A region will at least

     * be in one of

     * <code>ENABLED</code>, <code>MOUSE_OVER</code>, <code>PRESSED</code>

     * or <code>DISABLED</code>.

     *

     * @see SynthConstants

     * @return State of Component

     */

    public int getComponentState() {

        return state;

    }

    /**

     * Resets the state of the Context.

     */

    void reset(JComponent component, Region region, SynthStyle style,

               int state) {

        this.component = component;

        this.region = region;

        this.style = style;

        this.state = state;

    }

    void dispose() {

        this.component = null;

        this.style = null;

        releaseContext(this);

    }

    /**

     * Convenience method to get the Painter from the current SynthStyle.

     * This will NEVER return null.

     */

    SynthPainter getPainter() {

        SynthPainter painter = getStyle().getPainter(this);

        if (painter != null) {

            return painter;

        }

        return SynthPainter.NULL_PAINTER;

    }

}