Java tutorial
/* * Copyright 2015 herd contributors * * 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.finra.dm.service.helper; import java.io.StringReader; import java.util.HashMap; import java.util.Map; import java.util.Properties; import java.util.UUID; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathFactory; import org.apache.commons.collections.CollectionUtils; import org.apache.commons.lang3.StringUtils; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import org.w3c.dom.Document; import org.xml.sax.InputSource; import org.finra.dm.core.DmDateUtils; import org.finra.dm.core.helper.ConfigurationHelper; import org.finra.dm.dao.helper.DmDaoSecurityHelper; import org.finra.dm.dao.helper.JavaPropertiesHelper; import org.finra.dm.model.dto.ConfigurationValue; import org.finra.dm.model.jpa.BusinessObjectDataEntity; import org.finra.dm.model.api.xml.BusinessObjectDataKey; /** * Default implementation of the builder for SQS messages. Constructs an ESB message based on given data. To use a different implementation overwrite the bean * defined in ServiceSpringModuleConfig.sqsMessageBuilder(). */ @Component public class DefaultSqsMessageBuilder implements SqsMessageBuilder { @Autowired private DmDaoHelper dmDaoHelper; @Autowired private DmDaoSecurityHelper dmDaoSecurityHelper; @Autowired private ConfigurationHelper configurationHelper; @Autowired private VelocityHelper velocityHelper; @Autowired private JavaPropertiesHelper javaPropertiesHelper; private DocumentBuilder documentBuilder; private XPath xpath; public DefaultSqsMessageBuilder() throws ParserConfigurationException { documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); xpath = XPathFactory.newInstance().newXPath(); } @Override public String buildSystemMonitorResponse(String systemMonitorRequestPayload) { return evaluateVelocityTemplate( ConfigurationValue.DM_NOTIFICATION_SQS_SYS_MONITOR_RESPONSE_VELOCITY_TEMPLATE, getIncomingMessageValueMap(systemMonitorRequestPayload, ConfigurationValue.DM_NOTIFICATION_SQS_SYS_MONITOR_REQUEST_XPATH_PROPERTIES), "systemMonitorResponse"); } @Override public String buildBusinessObjectDataStatusChangeMessage(BusinessObjectDataKey businessObjectDataKey, String newBusinessObjectDataStatus, String oldBusinessObjectDataStatus) { // Create a context map of values that can be used when building the message. Map<String, Object> velocityContextMap = new HashMap<>(); velocityContextMap.put("businessObjectDataKey", businessObjectDataKey); velocityContextMap.put("newBusinessObjectDataStatus", newBusinessObjectDataStatus); velocityContextMap.put("oldBusinessObjectDataStatus", oldBusinessObjectDataStatus); BusinessObjectDataEntity businessObjectDataEntity = dmDaoHelper .getBusinessObjectDataEntity(businessObjectDataKey); velocityContextMap.put("businessObjectDataId", businessObjectDataEntity.getId()); // Evaluate the template and return the value. return evaluateVelocityTemplate( ConfigurationValue.DM_NOTIFICATION_SQS_BUSINESS_OBJECT_DATA_STATUS_CHANGE_VELOCITY_TEMPLATE, velocityContextMap, "businessObjectDataStatusChangeEvent"); } /** * Evaluates a velocity template if one is defined for the specified configuration value. * * @param configurationValue the configuration value of the optional velocity template. If the configuration value returned is null, null will be returned. * @param contextMap the optional context map of additional keys and values to place in the velocity context. This can be useful if you have values from an * incoming request message you want to make available to velocity to use in the building of the outgoing response message. * @param velocityTemplateName the velocity template name used when Velocity logs error messages. * * @return the evaluated velocity template. */ private String evaluateVelocityTemplate(ConfigurationValue configurationValue, Map<String, Object> contextMap, String velocityTemplateName) { // Initialize the message text to null which will cause a message to not be sent. String messageText = null; // Get the velocity template and only process it if one is configured. String velocityTemplate = configurationHelper.getProperty(configurationValue); if (StringUtils.isNotBlank(velocityTemplate)) { // Create and populate the velocity context with dynamic values. Note that we can't use periods within the context keys since they can't // be referenced in the velocity template (i.e. they're used to separate fields with the context object being referenced). Map<String, Object> context = new HashMap<>(); context.put(ConfigurationValue.DM_NOTIFICATION_SQS_ENVIRONMENT.getKey().replace('.', '_'), configurationHelper.getProperty(ConfigurationValue.DM_NOTIFICATION_SQS_ENVIRONMENT)); context.put("current_time", DmDateUtils.now().toString()); context.put("uuid", UUID.randomUUID().toString()); context.put("username", dmDaoSecurityHelper.getCurrentUsername()); context.put("StringUtils", StringUtils.class); context.put("CollectionUtils", CollectionUtils.class); // Populate the context map entries into the velocity context. for (Map.Entry<String, Object> mapEntry : contextMap.entrySet()) { context.put(mapEntry.getKey(), mapEntry.getValue()); } messageText = velocityHelper.evaluate(velocityTemplate, context, velocityTemplateName); } // Return the message text. return messageText; } /** * Gets an incoming message value map from a message payload. * * @param payload the incoming message payload. * @param configurationValue the configuration value for the XPath expression properties. * * @return the incoming message value map. */ private Map<String, Object> getIncomingMessageValueMap(String payload, ConfigurationValue configurationValue) { // This method is generic and could be placed in a generic helper, but since it's use is limited to only getting values from an incoming message // to produce an outgoing message, it is fine in this class. Properties xpathProperties; try { String xpathPropertiesString = configurationHelper.getProperty(configurationValue); xpathProperties = javaPropertiesHelper.getProperties(xpathPropertiesString); } catch (Exception e) { throw new IllegalStateException("Unable to load XPath properties from configuration with key '" + configurationValue.getKey() + "'", e); } // Create a map that will house keys that map to values retrieved from the incoming message via the XPath expressions. Map<String, Object> incomingMessageValuesMap = new HashMap<>(); // Evaluate all the XPath expressions on the incoming message and store the results in the map. // If validation is desired, an XPath expression can be used to verify that the incoming message contains a valid path in the payload. // If no XPath expressions are used, then it is assumed that the message is valid and the message will be processed // with no incoming values. Document document; try { document = documentBuilder.parse(new InputSource(new StringReader(payload))); } catch (Exception e) { throw new IllegalArgumentException("Payload is not valid XML:\n" + payload, e); } for (String key : xpathProperties.stringPropertyNames()) { // Get the XPath expression. String xpathExpression = xpathProperties.getProperty(key); try { // Evaluate the expression and store the result in the map keyed by the XPath expression key. // A document is required here as opposed to an input source since an input source yields a bug when the input XML contains a namespace. incomingMessageValuesMap.put(key, xpath.evaluate(xpathExpression, document)); } catch (Exception ex) { // If any XPath expressions couldn't be evaluated against the incoming payload, throw an exception. // If the caller is the incoming JMS processing logic, it will log a debug message because it doesn't know which message it is // processing. If this exception is thrown, it assumes the incoming message isn't the one it is processing and moves on to the next message // processing routine for a different incoming message. // If the XPath expression configured is incorrect (i.e. an internal server error), then the incoming JMS processing logic will eventually // find no successful handler and will log an error which can be looked into further. That debug message would then be useful. throw new IllegalStateException("XPath expression \"" + xpathExpression + "\" could not be evaluated against payload \"" + payload + "\".", ex); } } return incomingMessageValuesMap; } }