| /* |
| * Copyright 2008 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.user.client.ui; |
| |
| import com.google.gwt.event.logical.shared.HasValueChangeHandlers; |
| import com.google.gwt.user.client.TakesValue; |
| |
| /** |
| * Extends {@link TakesValue} to allow the value to be pulled back out, and to |
| * throw {@link com.google.gwt.event.logical.shared.ValueChangeEvent |
| * ValueChangeEvent} events. |
| * <p> |
| * An object that implements this interface should be a user input widget, where |
| * the user and programmer can both set and get the object's value. It is |
| * intended to provide a unified interface to widgets with "atomic" values, like |
| * Strings and Dates. |
| * |
| * @param <T> the type of value |
| */ |
| public interface HasValue<T> extends TakesValue<T>, HasValueChangeHandlers<T> { |
| |
| /** |
| * Gets this object's value. |
| * |
| * @return the object's value |
| */ |
| T getValue(); |
| |
| /** |
| * Sets this object's value without firing any events. This should be |
| * identical to calling setValue(value, false). |
| * <p> |
| * It is acceptable to fail assertions or throw (documented) unchecked |
| * exceptions in response to bad values. |
| * <p> |
| * Widgets must accept null as a valid value. By convention, setting a widget to |
| * null clears value, calling getValue() on a cleared widget returns null. Widgets |
| * that can not be cleared (e.g. {@link CheckBox}) must find another valid meaning |
| * for null input. |
| * |
| * @param value the object's new value |
| */ |
| void setValue(T value); |
| |
| /** |
| * Sets this object's value. Fires |
| * {@link com.google.gwt.event.logical.shared.ValueChangeEvent} when |
| * fireEvents is true and the new value does not equal the existing value. |
| * <p> |
| * It is acceptable to fail assertions or throw (documented) unchecked |
| * exceptions in response to bad values. |
| * |
| * @param value the object's new value |
| * @param fireEvents fire events if true and value is new |
| */ |
| void setValue(T value, boolean fireEvents); |
| } |