Java tutorial
/** * The MIT License (MIT) * * Copyright (c) 2011-2016 Incapture Technologies LLC * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package rapture.server; import rapture.common.exception.ExceptionToString; import rapture.common.exception.RaptureException; import rapture.common.exception.RaptureExceptionFactory; import rapture.common.impl.jackson.JacksonUtilChecked; import java.io.IOException; import java.lang.reflect.Field; import java.net.HttpURLConnection; import java.util.LinkedList; import java.util.List; import org.apache.commons.lang.StringUtils; import org.apache.log4j.Logger; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.databind.JsonMappingException; import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException; /** * @author bardhi * @since 10/28/14. */ public class ArgumentParser { private static final Logger log = Logger.getLogger(ArgumentParser.class); public static <T> T parsePayload(String json, Class<T> tClass) { final int errorCode = HttpURLConnection.HTTP_BAD_REQUEST; try { return JacksonUtilChecked.objectFromJson(json, tClass); } catch (UnrecognizedPropertyException e) { List<String> references = getReferences(e); if (references.size() > 1) { String referencesString = StringUtils.join(references.subList(0, references.size()), "->"); throw RaptureExceptionFactory.create(errorCode, String.format("Bad value for argument \"%s\". Child field \"%s\" not recognized.", references.get(0), referencesString), e); } else { throw RaptureExceptionFactory.create(errorCode, String.format( "Unrecognized parameter \"%s\" passed to API call", e.getUnrecognizedPropertyName()), e); } } catch (JsonMappingException e) { List<String> references = getReferences(e); if (references.size() > 1) { String referencesString = StringUtils.join(references.subList(0, references.size()), "->"); throw RaptureExceptionFactory.create(errorCode, String.format("Bad value for argument \"%s\". The problem is in the child field \"%s\": %s", references.get(0), referencesString, getReadableMessage(e)), e); } else if (references.size() > 0) { throw RaptureExceptionFactory.create(errorCode, String.format("Bad value for argument \"%s\": %s", references.get(0), getReadableMessage(e)), e); } else { RaptureException raptureException = RaptureExceptionFactory.create(errorCode, "Error reading arguments: " + e.getMessage(), e); log.error(String.format("exception id [%s]; json [%s]", raptureException.getId(), json)); throw raptureException; } } catch (JsonParseException e) { RaptureException raptureException = RaptureExceptionFactory.create(errorCode, "Bad/incomplete arguments passed in: " + e.getMessage(), e); log.error(String.format("exception id [%s]; json [%s]", raptureException.getId(), json)); throw raptureException; } catch (IOException e) { RaptureException raptureException = RaptureExceptionFactory.create(errorCode, "Error reading arguments: " + e.getMessage(), e); log.error(String.format("exception id [%s]; json [%s]", raptureException.getId(), json)); throw raptureException; } } /** * Having to do this kind of sucks, but we need to: the getMessage() method of JsonMappingException appends some information to the message that is useful, * but not very legible and exposes Java internals. We need to have as much of a language-agnostic message as possible here, since different languages will * be using the API and we should not expose Java errors. To do this, we need to get the plain error message that happens to be stored in the private field * detailMessage of the Throwable class (parent of JsonMappingException) * * @param e * @return */ private static String getReadableMessage(JsonMappingException e) { Field detailMessageField = null; try { detailMessageField = Throwable.class.getDeclaredField("detailMessage"); } catch (NoSuchFieldException e1) { log.error("Error getting readable message from exception: " + ExceptionToString.format(e1)); } Object value = null; if (detailMessageField != null) { detailMessageField.setAccessible(true); try { value = detailMessageField.get(e); } catch (IllegalAccessException e1) { log.error("Error getting readable message from exception: " + ExceptionToString.format(e1)); } } if (value != null) { return value.toString(); } else { return e.getMessage(); // fallback value } } private static List<String> getReferences(JsonMappingException e) { List<JsonMappingException.Reference> references = e.getPath(); List<String> ret = new LinkedList<>(); if (references != null) { for (JsonMappingException.Reference reference : references) { ret.add(reference.getFieldName()); } } return ret; } }