com.google.gwt.gen2.commonevent.shared.BeforeOpenEvent.java Source code

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Here is the source code for com.google.gwt.gen2.commonevent.shared.BeforeOpenEvent.java

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/*
 * Copyright 2009 Google 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 com.google.gwt.gen2.commonevent.shared;

import com.google.gwt.event.shared.GwtEvent;

/**
 * Represents an event that should fire after open. When a tree item receives a
 * request to open for the first time the isFirstTime flag will be set.
 * 
 * @param <T> the type being opened
 */
public class BeforeOpenEvent<T> extends GwtEvent<BeforeOpenHandler<T>> {
    /**
     * Handler type.
     */
    private static Type<BeforeOpenHandler<?>> TYPE;

    /**
     * Fires a beforeOpen event on all registered handlers in the handler manager.
     * If no such handlers exist, this method will do nothing.
     * 
     * @param <T> the target type
     * @param <S> The event source
     * @param source the source of the handlers
     * @param target the target
     */
    public static <T, S extends HasBeforeOpenHandlers<T>> void fire(S source, T target, boolean isFirstTime) {
        if (TYPE != null) {
            BeforeOpenEvent<T> event = new BeforeOpenEvent<T>(target, isFirstTime);
            source.fireEvent(event);
        }
    }

    /**
     * Fires a beforeOpen event on all registered handlers in the handler source.
     * If no such handlers exist, this method will do nothing.
     * 
     * @param <T> the target and event type
     * @param source the source of the handlers
     */
    public static <T extends HasBeforeOpenHandlers<T>> void fire(T source, boolean isFirstTime) {
        fire(source, source, isFirstTime);
    }

    public static Type<BeforeOpenHandler<?>> getType() {
        if (TYPE == null) {
            TYPE = new Type<BeforeOpenHandler<?>>();
        }
        return TYPE;
    }

    private final T target;

    /**
     * Flag to keep track of the first time @FastTreeItem has been opened.
     */
    private boolean isFirstTime;

    /**
     * Creates a new before open event.
     * 
     * @param target the ui object being opened
     * @param isFirstTime
     */
    protected BeforeOpenEvent(T target, boolean isFirstTime) {
        this.target = target;
        this.isFirstTime = isFirstTime;
    }

    // Because of type erasure, our static type is
    // wild carded, yet the "real" type should use our I param.
    @SuppressWarnings("unchecked")
    @Override
    public final Type<BeforeOpenHandler<T>> getAssociatedType() {
        return (Type) TYPE;
    }

    /**
     * Gets the target.
     * 
     * @return the target
     */
    public T getTarget() {
        return target;
    }

    public boolean isFirstTime() {
        return isFirstTime;
    }

    public void setFirstTime(boolean isFirstTime) {
        this.isFirstTime = isFirstTime;
    }

    @Override
    protected void dispatch(BeforeOpenHandler<T> handler) {
        handler.onBeforeOpen(this);
    }
}