org.drools.guvnor.client.decisiontable.cells.PopupBoundPatternDropDownEditCell.java Source code

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Here is the source code for org.drools.guvnor.client.decisiontable.cells.PopupBoundPatternDropDownEditCell.java

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/*
 * Copyright 2011 JBoss Inc
 * 
 * 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.
 */
package org.drools.guvnor.client.decisiontable.cells;

import java.util.List;

import org.drools.guvnor.client.decisiontable.widget.BoundFactsChangedEvent;

import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.client.Element;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyDownEvent;
import com.google.gwt.event.dom.client.KeyDownHandler;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.user.client.ui.ListBox;
import com.google.gwt.user.client.ui.PopupPanel.PositionCallback;
import org.drools.guvnor.client.messages.Constants;

/**
 * A Popup drop-down Editor for bound Fact Patterns. This cell listens for
 * PatternsChangedEvents so that it's content can be maintained as and when
 * Patterns are added, deleted or edited.
 */
public class PopupBoundPatternDropDownEditCell extends AbstractPopupEditCell<String, String>
        implements BoundFactsChangedEvent.Handler {

    private final ListBox listBox;

    public PopupBoundPatternDropDownEditCell(EventBus eventBus, boolean isReadOnly) {
        super(isReadOnly);
        this.listBox = new ListBox();

        // Tabbing out of the ListBox commits changes
        listBox.addKeyDownHandler(new KeyDownHandler() {

            public void onKeyDown(KeyDownEvent event) {
                boolean keyTab = event.getNativeKeyCode() == KeyCodes.KEY_TAB;
                boolean keyEnter = event.getNativeKeyCode() == KeyCodes.KEY_ENTER;
                if (keyEnter || keyTab) {
                    commit();
                }
            }

        });

        vPanel.add(listBox);

        //Wire-up the events
        eventBus.addHandler(BoundFactsChangedEvent.TYPE, this);
    }

    @Override
    public void render(Context context, String value, SafeHtmlBuilder sb) {
        if (value != null) {
            sb.append(renderer.render(value));
        }
    }

    public void onBoundFactsChanged(BoundFactsChangedEvent event) {
        setFactBindings(event.getFactBindings());
    }

    /**
     * Set content of drop-down.
     * 
     * @param factBindings
     */
    public void setFactBindings(List<String> factBindings) {
        listBox.clear();
        for (String binding : factBindings) {
            listBox.addItem(binding);
        }
        listBox.setEnabled(listBox.getItemCount() > 0);
        if (listBox.getItemCount() == 0) {
            listBox.addItem(Constants.INSTANCE.NoPatternBindingsAvailable());
        }
    }

    // Commit the change
    @Override
    protected void commit() {

        //If there are no pattern bindings don't update the model
        if (!listBox.isEnabled()) {
            return;
        }

        // Update value
        String value = null;
        int selectedIndex = listBox.getSelectedIndex();
        if (selectedIndex >= 0) {
            value = listBox.getValue(selectedIndex);
        }
        setValue(lastContext, lastParent, value);
        if (valueUpdater != null) {
            valueUpdater.update(value);
        }
        panel.hide();

    }

    // Start editing the cell
    @Override
    protected void startEditing(final Context context, final Element parent, final String value) {

        // Select the appropriate item
        boolean emptyValue = (value == null);
        if (emptyValue) {
            listBox.setSelectedIndex(0);
        } else {
            for (int i = 0; i < listBox.getItemCount(); i++) {
                if (listBox.getValue(i).equals(value)) {
                    listBox.setSelectedIndex(i);
                    break;
                }
            }
        }

        panel.setPopupPositionAndShow(new PositionCallback() {
            public void setPosition(int offsetWidth, int offsetHeight) {
                panel.setPopupPosition(parent.getAbsoluteLeft() + offsetX, parent.getAbsoluteTop() + offsetY);

                // Focus the first enabled control
                Scheduler.get().scheduleDeferred(new ScheduledCommand() {

                    public void execute() {
                        listBox.setFocus(true);
                    }

                });
            }
        });

    }

}