Java tutorial
/* * Copyright (c) 2009-2011 Lockheed Martin Corporation * * 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.eurekastreams.web.client.ui.common.form; import java.io.Serializable; import java.util.ArrayList; import java.util.HashMap; import java.util.LinkedList; import java.util.List; import org.eurekastreams.web.client.events.EventBus; import org.eurekastreams.web.client.events.ExceptionResponseEvent; import org.eurekastreams.web.client.events.Observer; import org.eurekastreams.web.client.events.PreSwitchedHistoryViewEvent; import org.eurekastreams.web.client.events.PreventHistoryChangeEvent; import org.eurekastreams.web.client.events.SubmitFormIfChangedEvent; import org.eurekastreams.web.client.events.data.ValidationExceptionResponseEvent; import org.eurekastreams.web.client.jsni.WidgetJSNIFacadeImpl; import org.eurekastreams.web.client.model.BaseModel; import org.eurekastreams.web.client.model.Insertable; import org.eurekastreams.web.client.model.Updateable; import org.eurekastreams.web.client.ui.Session; import org.eurekastreams.web.client.ui.common.form.elements.FormElement; import org.eurekastreams.web.client.ui.pages.master.StaticResourceBundle; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.History; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.Anchor; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.Hyperlink; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.Widget; /** * The Form Builder. * */ public class FormBuilder extends FlowPanel { /** * Method to call on the BaseModel. (Forms never fetch or delete). */ public enum Method { /** * Call the Insert method. */ INSERT, /** * Call the Update method. */ UPDATE } /** * The command to exe on cancel. */ private Command onCancelCommand; /** * The base model. */ private final BaseModel baseModel; /** * The method. */ private final Method method; /** * The title of the form. */ private final Label formTitle = new Label(); /** * Contains the form. */ private final FlowPanel formContainer = new FlowPanel(); /** * Contains the inner elements of the form. */ private final FlowPanel formElementsContainer = new FlowPanel(); /** * The error box for evil. */ private final FlowPanel errorBox = new FlowPanel(); /** * The fade panel to disable controls while submitting. */ private final FlowPanel fadePanel = new FlowPanel(); /** * The submit button of the form. */ private final Anchor submitButton = new Anchor(""); /** * The cancel button of the form. */ private final Hyperlink cancelButton = new Hyperlink("Cancel", History.getToken()); /** * The processing spinner. */ private final Label processingSpinny = new Label("Processing..."); /** * The data of the form. */ private final List<FormElement> data = new LinkedList<FormElement>(); /** * The original values of the form, to see if anything has changed. */ private final HashMap<String, Serializable> originalValues = new HashMap<String, Serializable>(); /** * Did the user add a "last form element". */ private boolean addedLastFormElement = false; /** * Is the form inactive. */ private boolean inactive = false; /** * If should scroll to top of window on ValidationExceptionResponseEvent. */ private boolean scrollToTopOnValidationError = true; /** If events are currently wired to the event bus. */ private boolean eventsWired; /** Event handler. */ private Observer<ValidationExceptionResponseEvent> validationExceptionResponseHandler; /** Event handler. */ private Observer<ExceptionResponseEvent> exceptionResponseHandler; /** Event handler. */ private Observer<PreSwitchedHistoryViewEvent> preSwitchedHistoryViewHandler; /** Event handler. */ private Observer<SubmitFormIfChangedEvent> submitFormIfChangedHandler; /** * Constructor. * * @param title * the form title. * @param inBaseModel * the base model to use to persist data. * @param inMethod * the method to call on the base model. */ public FormBuilder(final String title, final BaseModel inBaseModel, final Method inMethod) { this(title, inBaseModel, inMethod, true); } /** * Constructor. * * @param title * the form title. * @param inBaseModel * the base model to use to persist data. * @param inMethod * the method to call on the base model. * @param inScrollToTopOnValidationError * scroll to top on ValidationExceptionResponseEvent. */ public FormBuilder(final String title, final BaseModel inBaseModel, final Method inMethod, final boolean inScrollToTopOnValidationError) { scrollToTopOnValidationError = inScrollToTopOnValidationError; baseModel = inBaseModel; method = inMethod; submitButton.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formSubmitButton()); cancelButton.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formCancelButton()); errorBox.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formErrorBox()); formContainer.add(errorBox); formContainer.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formContainer()); formContainer.add(formElementsContainer); fadePanel.setVisible(false); fadePanel.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formDisable()); formContainer.add(fadePanel); formContainer.add(submitButton); processingSpinny.setVisible(false); processingSpinny.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formSubmitSpinny()); processingSpinny.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formProcessingSpinny()); formContainer.add(processingSpinny); formContainer.add(cancelButton); if (!title.equals("")) { formTitle.setText(title); formTitle.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formTitle()); this.add(formTitle); } this.add(formContainer); errorBox.setVisible(false); submitButton.addClickHandler(new ClickHandler() { public void onClick(final ClickEvent event) { submit(); } }); cancelButton.addClickHandler(new ClickHandler() { public void onClick(final ClickEvent arg0) { inactive = true; if (onCancelCommand != null) { onCancelCommand.execute(); } } }); createEventHandlers(); // wireEventHandlers(); } /** * {@inheritDoc} */ @Override protected void onAttach() { super.onAttach(); wireEventHandlers(); } /** * {@inheritDoc} */ @Override protected void onDetach() { super.onDetach(); unwireEventHandlers(); } /** * Creates the event handlers used with the event bus. */ private void createEventHandlers() { validationExceptionResponseHandler = new Observer<ValidationExceptionResponseEvent>() { public void update(final ValidationExceptionResponseEvent event) { List<String> errors = new ArrayList<String>(); for (FormElement element : data) { String error = event.getResponse().getErrors().get(element.getKey()); if (error != null) { errors.add(error); } } if (!errors.isEmpty()) { errorBox.clear(); resetSubmitButton(); String errorBoxText = new String("Please correct the following errors:<ul>"); for (FormElement element : data) { String error = event.getResponse().getErrors().get(element.getKey()); if (error != null) { errorBox.setVisible(true); errorBoxText += "<li>" + error + "</li>"; element.onError(error); } else { element.onSuccess(); } } errorBoxText += "</ul>"; errorBox.add(new HTML(errorBoxText)); if (scrollToTopOnValidationError) { Window.scrollTo(0, 0); } } } }; exceptionResponseHandler = new Observer<ExceptionResponseEvent>() { public void update(final ExceptionResponseEvent event) { if (event.getModel() == baseModel) { resetSubmitButton(); } } }; preSwitchedHistoryViewHandler = new Observer<PreSwitchedHistoryViewEvent>() { public void update(final PreSwitchedHistoryViewEvent arg1) { if (hasFormChanged()) { if (new WidgetJSNIFacadeImpl() .confirm("The form has been changed. Do you wish to save changes?")) { EventBus eventBus = Session.getInstance().getEventBus(); eventBus.notifyObservers(new PreventHistoryChangeEvent()); eventBus.notifyObservers(new SubmitFormIfChangedEvent()); } } } }; submitFormIfChangedHandler = new Observer<SubmitFormIfChangedEvent>() { public void update(final SubmitFormIfChangedEvent arg1) { if (hasFormChanged()) { submit(); } } }; } /** * Attaches the event handlers to the event bus. */ public void wireEventHandlers() { if (!eventsWired) { final EventBus eventBus = Session.getInstance().getEventBus(); eventBus.addObserver(ValidationExceptionResponseEvent.class, validationExceptionResponseHandler); eventBus.addObserver(ExceptionResponseEvent.class, exceptionResponseHandler); eventBus.addObserver(PreSwitchedHistoryViewEvent.class, preSwitchedHistoryViewHandler); eventBus.addObserver(SubmitFormIfChangedEvent.class, submitFormIfChangedHandler); eventsWired = true; } } /** * Removes the event handlers from the event bus. */ public void unwireEventHandlers() { if (eventsWired) { final EventBus eventBus = Session.getInstance().getEventBus(); eventBus.removeObserver(ValidationExceptionResponseEvent.class, validationExceptionResponseHandler); eventBus.removeObserver(ExceptionResponseEvent.class, exceptionResponseHandler); eventBus.removeObserver(PreSwitchedHistoryViewEvent.class, preSwitchedHistoryViewHandler); eventBus.removeObserver(SubmitFormIfChangedEvent.class, submitFormIfChangedHandler); eventsWired = false; } } /** * Cancel the form manually. */ public void turnOffChangeCheck() { inactive = true; } /** * Has the form changed? * * @return has the form changed? */ private boolean hasFormChanged() { boolean changed = false; for (FormElement element : data) { if (originalValues.containsKey(element.getKey()) && (originalValues.get(element.getKey()) != null && !originalValues.get(element.getKey()).equals(element.getValue())) || (element.getValue() != null && !element.getValue().equals(originalValues.get(element.getKey())))) { changed = true; } } return changed && !inactive; } /** * Submit the form. */ private void submit() { processingSpinny.setVisible(true); fadePanel.setVisible(true); submitButton.setVisible(false); HashMap<String, Serializable> dataValues = new HashMap<String, Serializable>(); for (FormElement element : data) { dataValues.put(element.getKey(), element.getValue()); originalValues.put(element.getKey(), element.getValue()); } if (method.equals(Method.INSERT)) { ((Insertable) baseModel).insert(dataValues); } else { ((Updateable) baseModel).update(dataValues); } } /** * Happens on success of the form. */ public void onSuccess() { resetSubmitButton(); errorBox.clear(); errorBox.setVisible(false); for (FormElement element : data) { element.onSuccess(); } } /** * Sets the CSS class on the Submit button. Used if you're changing it to say, an update button. * * @param cssClass * the css class. */ public void setSubmitButtonClass(final String cssClass) { submitButton.removeStyleName(StaticResourceBundle.INSTANCE.coreCss().formSubmitButton()); submitButton.addStyleName(cssClass); } /** * Used to inject widgets in the form container itself. Useful if you need to add something after the submit and * cancel. * * @param widget * the widget. */ public void addWidgetToFormContainer(final Widget widget) { formContainer.add(widget); } /** * Sets the token for when the user clicks cancel. * * @param token * the token. */ public void setOnCancelHistoryToken(final String token) { cancelButton.setTargetHistoryToken(token); } /** * Gives a command to execute on cancel. * * @param inOnCancelCommand * the command. */ public void addOnCancelCommand(final Command inOnCancelCommand) { onCancelCommand = inOnCancelCommand; } /** * Adds a form element to the form. * * @param element * the form element. */ public void addFormElement(final FormElement element) { if (element instanceof Widget) { ((Widget) element).addStyleName(StaticResourceBundle.INSTANCE.coreCss().formElement()); if (addedLastFormElement) { formElementsContainer.insert((Widget) element, formElementsContainer.getWidgetCount() - 1); } else { formElementsContainer.add((Widget) element); } } data.add(element); originalValues.put(element.getKey(), element.getValue()); } /** * Adds a "last form element". This is a form element that will ALWAYS stay at the bottom of the form Regardless of * others added. * * @param element * the element. */ public void addLastFormElement(final FormElement element) { if (element instanceof Widget) { ((Widget) element).addStyleName(StaticResourceBundle.INSTANCE.coreCss().formElement()); formElementsContainer.insert((Widget) element, formElementsContainer.getWidgetCount()); addedLastFormElement = true; } data.add(element); originalValues.put(element.getKey(), element.getValue()); } /** * Gets the form value from the key. * * @param key * the key. * @return the value. */ public Serializable getFormValue(final String key) { for (FormElement formElement : data) { if (formElement.getKey().equals(key)) { return formElement.getValue(); } } return null; } /** * Adds a form divider. */ public void addFormDivider() { Label divider = new Label(); divider.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formDivider()); formElementsContainer.add(divider); } /** * Reset the submit button. */ private void resetSubmitButton() { processingSpinny.setVisible(false); fadePanel.setVisible(false); submitButton.setVisible(true); } /** * Adds a clearing divider to the form. */ public void addClear() { FlowPanel clear = new FlowPanel(); clear.addStyleName(StaticResourceBundle.INSTANCE.coreCss().clear()); formElementsContainer.add(clear); } /** * Adds a form label to the form. * * @param header * the label. * @return the label. */ public Label addFormLabel(final String header) { Label subHeader = new Label(header); subHeader.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formLabel()); subHeader.addStyleName(StaticResourceBundle.INSTANCE.coreCss().formStandaloneLabel()); formElementsContainer.add(subHeader); return subHeader; } /** * Adds a widget to the form panel. * * @param w * the widget to add. */ public void addWidget(final Widget w) { formElementsContainer.add(w); } }