net.sf.mmm.client.ui.gwt.widgets.CollapseExpandButton.java Source code

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Here is the source code for net.sf.mmm.client.ui.gwt.widgets.CollapseExpandButton.java

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/* Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0
 * http://www.apache.org/licenses/LICENSE-2.0 */
package net.sf.mmm.client.ui.gwt.widgets;

import net.sf.mmm.client.ui.NlsBundleClientUiRoot;
import net.sf.mmm.client.ui.api.attribute.AttributeWriteCollapsed;
import net.sf.mmm.client.ui.api.common.CssStyles;
import net.sf.mmm.util.nls.api.NlsAccess;

import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.ui.Button;

/**
 * A {@link CollapseExpandButton} is a {@link Button} used to {@link #setCollapsed(boolean) collapse and
 * expand} a section that is typically located below it.
 * 
 * @author Joerg Hohwiller (hohwille at users.sourceforge.net)
 * @since 1.0.0
 */
public class CollapseExpandButton extends Button implements AttributeWriteCollapsed {

    /** The {@link CollapseHandler} given at construction time. */
    private final CollapseHandler collapseHandler;

    /** @see #isCollapsed() */
    private boolean collapsed;

    /**
     * The constructor.
     * 
     * @param collapseHandler is the {@link CollapseHandler} notified about collapsing and expanding.
     */
    public CollapseExpandButton(CollapseHandler collapseHandler) {

        // visual appearance is configured via CSS, only logical tagging via styles here...
        super("<span></span>");
        this.collapseHandler = collapseHandler;
        setStylePrimaryName(CssStyles.BUTTON);
        addStyleName(CssStyles.COLLAPSE_BUTTON);
        setTitle(getBundle().tooltipCollapse().getLocalizedMessage());
        ClickHandler handler = new ClickHandler() {

            @Override
            public void onClick(ClickEvent event) {

                setCollapsed(!CollapseExpandButton.this.collapsed, false);
            }
        };
        addClickHandler(handler);
        this.collapsed = false;
    }

    /**
     * @return the instance of {@link NlsBundleClientUiRoot}.
     */
    private NlsBundleClientUiRoot getBundle() {

        return NlsAccess.getBundleFactory().createBundle(NlsBundleClientUiRoot.class);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setCollapsed(boolean collapsed) {

        setCollapsed(collapsed, true);
    }

    /**
     * @param newCollapsed - see {@link #setCollapsed(boolean)}.
     * @param programmatic - see {@link net.sf.mmm.client.ui.api.event.UiEvent#isProgrammatic()}.
     */
    public void setCollapsed(boolean newCollapsed, boolean programmatic) {

        if (newCollapsed == this.collapsed) {
            return;
        }
        if (newCollapsed) {
            addStyleName(CssStyles.COLLAPSED);
            setTitle(getBundle().tooltipExpand().getLocalizedMessage());
        } else {
            removeStyleName(CssStyles.COLLAPSED);
            setTitle(getBundle().tooltipCollapse().getLocalizedMessage());
        }
        this.collapsed = newCollapsed;
        this.collapseHandler.onCollapse(newCollapsed, programmatic);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isCollapsed() {

        return this.collapsed;
    }

    /**
     * Interface for a handler that gets notified about {@link #onCollapse(boolean, boolean) collapsing and
     * expanding}.
     */
    public interface CollapseHandler {

        /**
         * This method is called to notify about collapsing and expanding. It has to implement the logic that
         * actually shows and hides things accordingly.
         * 
         * @param collapse - <code>true</code> if switched to collapsed state, <code>false</code> if switched to
         *        expanded state.
         * @param programmatic - see {@link net.sf.mmm.client.ui.api.event.UiEvent#isProgrammatic()}.
         */
        void onCollapse(boolean collapse, boolean programmatic);
    }

}