Java tutorial
/* * This library is part of Geranium - * an open source UI library for GWT. * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)- * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software, please see the * company website: http://www.alkacon.com * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package com.alkacon.geranium.client.ui.input; import com.alkacon.geranium.client.I_HasInit; import com.alkacon.geranium.client.ui.I_AutoHider; import com.alkacon.geranium.client.ui.css.I_InputLayoutBundle; import com.alkacon.geranium.client.ui.css.I_LayoutBundle; import java.util.HashMap; import java.util.Map; import com.google.gwt.event.logical.shared.HasValueChangeHandlers; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.event.shared.GwtEvent; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.event.shared.SimpleEventBus; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.Panel; /** * Widget class consisting of a group of radio buttons, of which at most one may be active.<p> * * This is mostly a 'convenience widget' for creating and handling multiple radio buttons as a single widget. * The radio buttons will be layed out vertically. If you need more control about the layout of the radio * buttons, use multiple {@link RadioButton} instances and link them with a {@link RadioButtonGroup}.<p> */ public class RadioButtonGroupWidget extends Composite implements I_FormWidget, HasValueChangeHandlers<String>, I_HasInit { /** The widget type identifier. */ public static final String WIDGET_TYPE = "radio"; /** The event bus. */ protected SimpleEventBus m_eventBus; /** The error display used by this widget. */ private ErrorWidget m_error = new ErrorWidget(); /** The radio button group for this radio button. */ private RadioButtonGroup m_group = new RadioButtonGroup(); /** The root panel containing all other components of this widget. */ private Panel m_panel = new FlowPanel(); /** A map which stores all radio buttons using their value as keys. */ private Map<String, RadioButton> m_radioButtons; /** * Creates a new instance from a map of strings.<p> * * The keys of the map are used as the values of the radio buttons, and the values of the map are used as labels * for the radio buttons. * * @param items the string map containing the select options */ public RadioButtonGroupWidget(Map<String, String> items) { init(items); } /** * @see com.google.gwt.event.logical.shared.HasValueChangeHandlers#addValueChangeHandler(com.google.gwt.event.logical.shared.ValueChangeHandler) */ public HandlerRegistration addValueChangeHandler(final ValueChangeHandler<String> handler) { return m_eventBus.addHandlerToSource(ValueChangeEvent.getType(), this, handler); } /** * @see com.google.gwt.user.client.ui.Widget#fireEvent(com.google.gwt.event.shared.GwtEvent) */ @Override public void fireEvent(GwtEvent<?> event) { m_eventBus.fireEventFromSource(event, this); } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#getApparentValue() */ public String getApparentValue() { return getFormValueAsString(); } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#getFieldType() */ public FieldType getFieldType() { return I_FormWidget.FieldType.STRING; } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#getFormValue() */ public Object getFormValue() { RadioButton button = m_group.getSelectedButton(); if (button == null) { return ""; } else { return button.getName(); } } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#getFormValueAsString() */ public String getFormValueAsString() { return (String) getFormValue(); } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#isEnabled() */ public boolean isEnabled() { boolean result = true; for (Map.Entry<String, RadioButton> entry : m_radioButtons.entrySet()) { if (!entry.getValue().isEnabled()) { result = false; } } return result; } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#reset() */ public void reset() { m_group.deselectButton(); } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#setAutoHideParent(com.alkacon.geranium.client.ui.I_AutoHider) */ public void setAutoHideParent(I_AutoHider autoHideParent) { // nothing to do } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#setEnabled(boolean) */ public void setEnabled(boolean enabled) { for (Map.Entry<String, RadioButton> entry : m_radioButtons.entrySet()) { entry.getValue().setEnabled(enabled); } } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#setErrorMessage(java.lang.String) */ public void setErrorMessage(String errorMessage) { m_error.setText(errorMessage); } /** * Sets the value of the widget.<p> * * @param value the new value */ public void setFormValue(Object value) { if (value == null) { value = ""; } if (value instanceof String) { String strValue = (String) value; if (strValue.equals("")) { // interpret empty string as "no radio button selected" reset(); } else { RadioButton button = m_radioButtons.get(value); m_group.selectButton(button); } } } /** * @see com.alkacon.geranium.client.ui.input.I_FormWidget#setFormValueAsString(java.lang.String) */ public void setFormValueAsString(String formValue) { setFormValue(formValue); } /** * Internal method for initializing the widget with a list of select options.<p> * * @param items the list of select options */ protected void init(Map<String, String> items) { initWidget(m_panel); m_eventBus = new SimpleEventBus(); m_radioButtons = new HashMap<String, RadioButton>(); for (Map.Entry<String, String> entry : items.entrySet()) { final RadioButton button = new RadioButton(entry.getKey(), entry.getValue()); button.setGroup(m_group); m_radioButtons.put(entry.getKey(), button); FlowPanel wrapper = new FlowPanel(); wrapper.add(button); m_panel.add(wrapper); } m_panel.add(m_error); m_panel.setStyleName(I_InputLayoutBundle.INSTANCE.inputCss().radioButtonGroup()); m_panel.addStyleName(I_LayoutBundle.INSTANCE.generalCss().textMedium()); m_group.setValueChangeTarget(this); } /** * Fires a ValueChangedEvent on this widget.<p> * * @param newValue the new value of this widget */ void fireValueChangedEvent(String newValue) { ValueChangeEvent.fire(this, newValue); } }