Java tutorial
/******************************************************************************* * * Copyright 2011 Spiffy UI Team * * 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.spiffyui.client.rest; import java.util.HashMap; import java.util.Map; import com.google.gwt.safehtml.shared.SafeHtmlUtils; /** * <p> * This exception represents a successful return from a REST call with an error * payload. This exception parses the payload and returns all the parts of the * exception. * </p> * * <p> * This exception follows the <a href="http://www.w3.org/TR/soap12-part1/#soapfault">SOAP fault format</a>. * The basic structure looks like this: * </p> * * <pre> * { * "Fault": { * "Code": { * "Value": "Sender", * "Subcode": { * "Value": "MessageTimeout" * } * }, * "Reason": { * "Text": "Sender Timeout" * }, * "Detail": { * "MaxTime": "P5M" * } * } * } * </pre> * * <p> * The fields in this class map to this JSON structure. * </p> * */ public class RESTException extends Exception { /** * This is a constant error code to indicate the response was not well formed JSON */ public static final String UNPARSABLE_RESPONSE = "UnparsableJSONResponse"; /** * This is a constant error code to indicate the JSON returned from the * server was parsable, but still invalid. */ public static final String INVALID_RESPONSE = "InvalidJSONResponse"; /** * This constant indicates that we were unable to contact the server. That * might be because we are offline or the server connection timed out. */ public static final String NO_SERVER_RESPONSE = "UnableToContactServer"; /** * This constant indicates that the server returned a 401, but did not * return the required authentication HTTP header */ public static final String NO_AUTH_HEADER = "NoAuthHeader"; /** * This constant indicates that the server returned a 401, but the required * HTTP header was invalid */ public static final String INVALID_AUTH_HEADER = "InvalidAuthHeader"; /** * This constant indicates that the server returned a 401, but did not * return the required authentication HTTP header */ public static final String XSS_ERROR = "PotentialXSSError"; /** * This constant indicates that the core server was not able to contact * the authentication server. */ public static final String AUTH_SERVER_UNAVAILABLE = "AuthServerUnavailable"; private static final long serialVersionUID = -1L; private String m_code; private String m_subcode; private String m_reason; private int m_responseCode; private String m_url; private Map<String, String> m_details = new HashMap<String, String>(); /** * Creates a new RESTException * * @param code the exception code * @param subcode the optional exception subcode * @param reason the optional exception reason * @param details the optional exception details * @param responseCode * the HTTP response code * @param url the URL for this exception */ public RESTException(String code, String subcode, String reason, Map<String, String> details, int responseCode, String url) { if (code == null) { throw new IllegalArgumentException("RESTException requires a code."); } m_code = semiUnescapeHtml(SafeHtmlUtils.fromString(code).asString()); if (subcode != null) { m_subcode = semiUnescapeHtml(SafeHtmlUtils.fromString(subcode).asString()); } if (reason != null) { m_reason = semiUnescapeHtml(SafeHtmlUtils.fromString(reason).asString()); } m_details = details; m_responseCode = responseCode; m_url = url; } /** * When an error response comes back from the server we want to encode it * as safe HTML since it comes from an untrusted source. However, the GWT * safe HTML utilities encode an apostrophe as a ' character and we * need to undo that since it's a common character in error messages. * * @param html the HTML to unescape * * @return the unescaped HTML */ private String semiUnescapeHtml(String html) { return html.replace("'", "'"); } /** * The code for the exception * * @return gets the return code for this exception - required */ public String getCode() { return m_code; } /** * The subcode for this exception * * @return the subcode - optional */ public String getSubcode() { return m_subcode; } /** * The reason for this exception * * @return the exception reason - required */ public String getReason() { return m_reason; } /** * The details for this exception * * @return a map of the details for this exception */ public Map<String, String> getDetails() { return m_details; } /** * Gets the server response code that came with this error message * * @return the HTTP response code */ public int getResponseCode() { return m_responseCode; } /** * Gets the URL that was called when this RESTException was thrown * * @return the URL */ public String getUrl() { return m_url; } /** * Gets a generic exception representing invalid JSON * * @param url the URL where this bad JSON came from * * @return the exception */ public static RESTException generateInvalidJSONException(String url) { return new RESTException(RESTException.INVALID_RESPONSE, "", "", new HashMap<String, String>(), -1, url); } @Override public String toString() { return "RESTException: " + m_code + ", " + m_subcode + ", " + m_reason; } }