Java tutorial
/* * 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.gdata.sample.hellogdata.client; import com.google.gwt.accounts.client.AuthSubStatus; import com.google.gwt.accounts.client.User; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.gdata.client.GData; import com.google.gwt.gdata.client.GDataSystemPackage; import com.google.gwt.gdata.client.finance.FinanceService; import com.google.gwt.gdata.client.finance.PortfolioEntry; import com.google.gwt.gdata.client.finance.PortfolioFeed; import com.google.gwt.gdata.client.finance.PortfolioFeedCallback; import com.google.gwt.gdata.client.finance.TransactionEntry; import com.google.gwt.gdata.client.finance.TransactionEntryCallback; import com.google.gwt.gdata.client.impl.CallErrorException; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.Label; /** * The following example demonstrates how to delete a transaction. */ public class FinanceDeleteTransactionDemo extends GDataDemo { /** * This method is used by the main sample app to obtain * information on this sample and a sample instance. * * @return An instance of this demo. */ public static GDataDemoInfo init() { return new GDataDemoInfo() { @Override public GDataDemo createInstance() { return new FinanceDeleteTransactionDemo(); } @Override public String getDescription() { return "<p>This sample demonstrates how to delete an existing " + "transaction within a portfolio of the authenticated user. " + "It deletes the first GOOG transaction in the " + "'GWT-Finance-Client' portfolio, which was created in a " + "preceeding example (an error will be generated if this " + "does not exist).</p>"; } @Override public String getName() { return "Finance - Deleting a transaction"; } }; } private FinanceService service; private FlexTable mainPanel; private final String scope = "http://finance.google.com/finance/feeds/"; /** * Setup the Finance service and create the main content panel. * If the user is not logged on to Finance display a message, * otherwise start the demo by retrieving the user's portfolios. */ public FinanceDeleteTransactionDemo() { mainPanel = new FlexTable(); initWidget(mainPanel); if (!GData.isLoaded(GDataSystemPackage.FINANCE)) { showStatus("Loading the GData Finance package...", false); GData.loadGDataApi(GDATA_API_KEY, new Runnable() { public void run() { startDemo(); } }, GDataSystemPackage.FINANCE); } else { startDemo(); } } /** * Delete a transaction entry using the Finance service and * the transaction entry uri. * On success and failure, display a status message. * * @param transactionEntryUri The uri of the transaction entry to delete */ private void deleteTransaction(String transactionEntryUri) { showStatus("Deleting transaction...", false); service.deleteEntry(transactionEntryUri, new TransactionEntryCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while deleting a transaction: " + caught.getMessage(), true); } public void onSuccess(TransactionEntry result) { showStatus("Deleted a transaction.", false); } }); } /** * Retrieve the portfolios feed using the Finance service and * the portfolios feed uri. In GData all get, insert, update * and delete methods always receive a callback defining success * and failure handlers. * Here, the failure handler displays an error message while the * success handler obtains the first Portfolio entry with a title * starting with "GWT-Finance-Client" and retrieves the first * transaction in the portfolio with the symbol "NASDAQ:GOOG", * this is the transaction that will be deleted. * If no transaction exists with this symbol, the request will fail. * If no portfolio is found, a message is displayed. * * @param portfoliosFeedUri The uri of the portfolios feed */ private void getPortfolios(String portfoliosFeedUri) { showStatus("Loading portfolios feed...", false); service.getPortfolioFeed(portfoliosFeedUri, new PortfolioFeedCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while retrieving the portfolios feed: " + caught.getMessage(), true); } public void onSuccess(PortfolioFeed result) { PortfolioEntry[] entries = result.getEntries(); PortfolioEntry targetPortfolio = null; for (PortfolioEntry entry : entries) { if (entry.getTitle().getText().startsWith("GWT-Finance-Client")) { targetPortfolio = entry; break; } } if (targetPortfolio == null) { showStatus("No portfolio found that contains 'GWT-Finance-Client' " + "in the title.", false); } else { final String ticker = "NASDAQ:GOOG"; int transactionId = 1; String transactionEntryUri = targetPortfolio.getEditLink().getHref() + "/positions/" + ticker + "/transactions/" + transactionId; getTransaction(transactionEntryUri); } } }); } /** * Retrieves the transaction entry corresponding to the given URI. * On failure display a status message. On success call * deleteTransaction to delete the transaction. Alternatively, * we could also have used result.deleteEntry, but the effect * is the same. * * @param transactionEntryUri The transaction entry uri */ private void getTransaction(String transactionEntryUri) { showStatus("Retrieving transaction...", false); service.getTransactionEntry(transactionEntryUri, new TransactionEntryCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while retrieving a transaction: " + caught.getMessage(), true); } public void onSuccess(TransactionEntry result) { if (result == null) { showStatus("No transaction found.", false); } else { String transactionEntryUri = result.getSelfLink().getHref(); deleteTransaction(transactionEntryUri); } } }); } /** * Displays a status message to the user. * * @param message The message to display. * @param isError Indicates whether the status is an error status. */ private void showStatus(String message, boolean isError) { mainPanel.clear(); mainPanel.insertRow(0); mainPanel.addCell(0); Label msg = new Label(message); if (isError) { msg.setStylePrimaryName("hm-error"); } mainPanel.setWidget(0, 0, msg); } /** * Starts this demo. */ private void startDemo() { service = FinanceService.newInstance("HelloGData_Finance_DeleteTransactionDemo_v2.0"); if (User.getStatus(scope) == AuthSubStatus.LOGGED_IN) { Button startButton = new Button("Delete a transaction"); startButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { getPortfolios("http://finance.google.com/finance/feeds/default/portfolios"); } }); mainPanel.setWidget(0, 0, startButton); } else { showStatus("You are not logged on to Google Finance.", true); } } }