ch.unifr.pai.twice.dragndrop.client.configuration.DragConfiguration.java Source code

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Here is the source code for ch.unifr.pai.twice.dragndrop.client.configuration.DragConfiguration.java

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package ch.unifr.pai.twice.dragndrop.client.configuration;

/*
 * Copyright 2013 Oliver Schmid
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import ch.unifr.pai.twice.dragndrop.client.factories.DropHandlerFactory;
import ch.unifr.pai.twice.dragndrop.client.intf.DragNDropHandler;

import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Widget;

/**
 * This configures the way how a drag can be visualized and restricted.
 * 
 * @author Oliver Schmid
 * 
 */
public class DragConfiguration {

    /**
     * The drag and drop handler to be used to react on drag events
     */
    private final DragNDropHandler handler;
    /**
     * A boundary box. A dragged widget can not leave this widget
     */
    private final Widget boundaryBox;
    /**
     * A HTML representation of the drag proxy (the semi-transparent visualization of a currently dragged widget)
     */
    private Element dragProxy;
    /**
     * If a drag proxy shall be used
     */
    private final boolean withProxy;

    /**
     * @return a default configuration without a drag proxy - the widget will be dragged itself (it does therefore not remain in its original position)
     */
    public static DragConfiguration withoutProxy() {
        return withoutProxy(null, null);
    }

    /**
     * @return a default configuration with a drag proxy
     */
    public static DragConfiguration withProxy() {
        return withProxy(null, null);
    }

    /**
     * @param handler
     * @return a default configuration with a custom {@link DragNDropHandler} without a drag proxy - the widget will be dragged itself (it does therefore not
     *         remain in its original position)
     */
    public static DragConfiguration withoutProxy(DragNDropHandler handler) {
        return withoutProxy(handler, null);
    }

    /**
     * @param handler
     * @return a default configuration with a custom {@link DragNDropHandler} with a proxy
     */
    public static DragConfiguration withProxy(DragNDropHandler handler) {
        return withProxy(handler, null);
    }

    /**
     * @param boundaryBox
     * @return a default configuration with a boundary box and without a drag proxy - the widget will be dragged itself (it does therefore not remain in its
     *         original position)
     */
    public static DragConfiguration withoutProxy(Widget boundaryBox) {
        return withoutProxy(null, boundaryBox);
    }

    /**
     * @param boundaryBox
     * @return a default configuration with a boundary box and with a drag proxy
     */
    public static DragConfiguration withProxy(Widget boundaryBox) {
        return withProxy(null, boundaryBox);
    }

    /**
     * @param handler
     * @param boundaryBox
     * @return a default configuration with a custom {@link DragNDropHandler}, a boundary box and without a drag proxy - the widget will be dragged itself (it
     *         does therefore not remain in its original position
     */
    public static DragConfiguration withoutProxy(DragNDropHandler handler, Widget boundaryBox) {
        return new DragConfiguration(handler, boundaryBox, false);
    }

    /**
     * @param handler
     * @param boundaryBox
     * @return a default configuration with a custom {@link DragNDropHandler}, a boundary box and with a drag proxy
     */
    public static DragConfiguration withProxy(DragNDropHandler handler, Widget boundaryBox) {
        return new DragConfiguration(handler, boundaryBox, true);
    }

    /**
     * A private constructor - use the static factory methods for instantiation
     * 
     * @param handler
     *            - if null, the {@link DropHandlerFactory#defaultHandler()} will be used.
     * @param boundaryBox
     * @param withProxy
     */
    private DragConfiguration(DragNDropHandler handler, Widget boundaryBox, boolean withProxy) {
        this.handler = handler != null ? handler : DropHandlerFactory.defaultHandler();
        this.boundaryBox = boundaryBox;
        this.withProxy = withProxy;
    }

    /**
     * @return the assigned drag and drop handler
     */
    public DragNDropHandler getDragNDropHandler() {
        return handler;
    }

    /**
     * @return the boundaries of permitted drags - if no boundary box is provided, this is 0
     */
    public int getMinX() {
        return boundaryBox != null ? boundaryBox.getAbsoluteLeft() : 0;
    }

    /**
     * @return the boundaries of permitted drags - if no boundary box is provided, this equals to the client width
     */
    public int getMaxX() {
        return boundaryBox != null ? boundaryBox.getAbsoluteLeft() + boundaryBox.getOffsetWidth()
                : Window.getClientWidth();
    }

    /**
     * @return the boundaries of permitted drags - if no boundary box is provided, this is 0
     */
    public int getMinY() {
        return boundaryBox != null ? boundaryBox.getAbsoluteTop() : 0;
    }

    /**
     * @return the boundaries of permitted drags - if no boundary box is provided, this equals to the client height
     */
    public int getMaxY() {
        return boundaryBox != null ? boundaryBox.getAbsoluteTop() + boundaryBox.getOffsetHeight()
                : Window.getClientHeight();
    }

    /**
     * @return if this drag configuration contains a proxy
     */
    public boolean isWithProxy() {
        return withProxy;
    }

    /**
     * @return the drag proxy
     */
    public Element getDragProxy() {
        return dragProxy;
    }

    /**
     * @param dragProxy
     */
    public void setDragProxy(Element dragProxy) {
        if (dragProxy.getId() != null && !dragProxy.getId().equals(""))
            dragProxy.setId(dragProxy.getId() + "PROXY");
        this.dragProxy = dragProxy;
    }

}