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Diffstat (limited to 'services/services-engine/src/main/java/org/onap/policy/apex/service/engine/event/impl/jsonprotocolplugin/Apex2JSONEventConverter.java')
| -rw-r--r-- | services/services-engine/src/main/java/org/onap/policy/apex/service/engine/event/impl/jsonprotocolplugin/Apex2JSONEventConverter.java | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/event/impl/jsonprotocolplugin/Apex2JSONEventConverter.java b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/event/impl/jsonprotocolplugin/Apex2JSONEventConverter.java new file mode 100644 index 000000000..3b21a29ca --- /dev/null +++ b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/event/impl/jsonprotocolplugin/Apex2JSONEventConverter.java @@ -0,0 +1,433 @@ +/*- + * ============LICENSE_START======================================================= + * Copyright (C) 2016-2018 Ericsson. All rights reserved. + * ================================================================================ + * 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. + * + * SPDX-License-Identifier: Apache-2.0 + * ============LICENSE_END========================================================= + */ + +package org.onap.policy.apex.service.engine.event.impl.jsonprotocolplugin; + +import java.util.ArrayList; +import java.util.List; + +import org.onap.policy.apex.context.SchemaHelper; +import org.onap.policy.apex.context.impl.schema.SchemaHelperFactory; +import org.onap.policy.apex.model.basicmodel.service.ModelService; +import org.onap.policy.apex.model.eventmodel.concepts.AxEvent; +import org.onap.policy.apex.model.eventmodel.concepts.AxEvents; +import org.onap.policy.apex.model.eventmodel.concepts.AxField; +import org.onap.policy.apex.service.engine.event.ApexEvent; +import org.onap.policy.apex.service.engine.event.ApexEventException; +import org.onap.policy.apex.service.engine.event.ApexEventProtocolConverter; +import org.onap.policy.apex.service.engine.event.ApexEventRuntimeException; +import org.onap.policy.apex.service.parameters.eventprotocol.EventProtocolParameters; +import org.slf4j.ext.XLogger; +import org.slf4j.ext.XLoggerFactory; + +import com.google.gson.Gson; +import com.google.gson.GsonBuilder; +import com.google.gson.JsonElement; +import com.google.gson.JsonObject; + +/** + * The Class Apex2JSONEventConverter converts {@link ApexEvent} instances to and from JSON string + * representations of Apex events. + * + * @author Liam Fallon (liam.fallon@ericsson.com) + */ +public class Apex2JSONEventConverter implements ApexEventProtocolConverter { + private static final XLogger LOGGER = XLoggerFactory.getXLogger(Apex2JSONEventConverter.class); + + // The parameters for the JSON event protocol + private JSONEventProtocolParameters jsonPars; + + /* + * (non-Javadoc) + * + * @see + * org.onap.policy.apex.service.engine.event.ApexEventProtocolConverter#init(org.onap.policy. + * apex.service.parameters.eventprotocol.EventProtocolParameters) + */ + @Override + public void init(final EventProtocolParameters parameters) { + // Check and get the JSON parameters + if (!(parameters instanceof JSONEventProtocolParameters)) { + final String errorMessage = "specified consumer properties are not applicable to the JSON event protocol"; + LOGGER.warn(errorMessage); + throw new ApexEventRuntimeException(errorMessage); + } + + jsonPars = (JSONEventProtocolParameters) parameters; + } + + /* + * (non-Javadoc) + * + * @see + * org.onap.policy.apex.service.engine.event.ApexEventConverter#toApexEvent(java.lang.String, + * java.lang.Object) + */ + @Override + public List<ApexEvent> toApexEvent(final String eventName, final Object eventObject) throws ApexEventException { + // Check the event eventObject + if (eventObject == null) { + LOGGER.warn("event processing failed, event is null"); + throw new ApexEventException("event processing failed, event is null"); + } + + // Cast the event to a string, if our conversion is correctly configured, this cast should + // always work + String jsonEventString = null; + try { + jsonEventString = (String) eventObject; + } catch (final Exception e) { + final String errorMessage = "error converting event \"" + eventObject + "\" to a string"; + LOGGER.debug(errorMessage, e); + throw new ApexEventRuntimeException(errorMessage, e); + } + + // The list of events we will return + final List<ApexEvent> eventList = new ArrayList<ApexEvent>(); + + try { + // We may have a single JSON object with a single event or an array of JSON objects + final Object decodedJsonObject = + new GsonBuilder().serializeNulls().create().fromJson(jsonEventString, Object.class); + + // Check if we have a list of objects + if (decodedJsonObject instanceof List) { + // Check if it's a list of JSON objects or a list of strings + @SuppressWarnings("unchecked") + final List<Object> decodedJsonList = (List<Object>) decodedJsonObject; + + // Decode each of the list elements in sequence + for (final Object jsonListObject : decodedJsonList) { + if (jsonListObject instanceof String) { + eventList.add(jsonStringApexEvent(eventName, (String) jsonListObject)); + } else if (jsonListObject instanceof JsonObject) { + eventList.add(jsonObject2ApexEvent(eventName, (JsonObject) jsonListObject)); + } else { + throw new ApexEventException("incoming event (" + jsonEventString + + ") is a JSON object array containing an invalid object " + jsonListObject); + } + } + } else { + eventList.add(jsonStringApexEvent(eventName, jsonEventString)); + } + } catch (final Exception e) { + final String errorString = + "Failed to unmarshal JSON event: " + e.getMessage() + ", event=" + jsonEventString; + LOGGER.warn(errorString, e); + throw new ApexEventException(errorString, e); + } + + // Return the list of events we have unmarshalled + return eventList; + } + + /* + * (non-Javadoc) + * + * @see + * org.onap.policy.apex.service.engine.event.ApexEventConverter#fromApexEvent(org.onap.policy. + * apex.service.engine.event.ApexEvent) + */ + @Override + public Object fromApexEvent(final ApexEvent apexEvent) throws ApexEventException { + // Check the Apex event + if (apexEvent == null) { + LOGGER.warn("event processing failed, Apex event is null"); + throw new ApexEventException("event processing failed, Apex event is null"); + } + + // Get the event definition for the event from the model service + final AxEvent eventDefinition = + ModelService.getModel(AxEvents.class).get(apexEvent.getName(), apexEvent.getVersion()); + + // Use a GSON Json object to marshal the Apex event to JSON + final Gson gson = new GsonBuilder().serializeNulls().setPrettyPrinting().create(); + final JsonObject jsonObject = new JsonObject(); + + jsonObject.addProperty(ApexEvent.NAME_HEADER_FIELD, apexEvent.getName()); + jsonObject.addProperty(ApexEvent.VERSION_HEADER_FIELD, apexEvent.getVersion()); + jsonObject.addProperty(ApexEvent.NAMESPACE_HEADER_FIELD, apexEvent.getNameSpace()); + jsonObject.addProperty(ApexEvent.SOURCE_HEADER_FIELD, apexEvent.getSource()); + jsonObject.addProperty(ApexEvent.TARGET_HEADER_FIELD, apexEvent.getTarget()); + + if (apexEvent.getExceptionMessage() != null) { + jsonObject.addProperty(ApexEvent.EXCEPTION_MESSAGE_HEADER_FIELD, apexEvent.getExceptionMessage()); + } + + for (final AxField eventField : eventDefinition.getFields()) { + final String fieldName = eventField.getKey().getLocalName(); + + if (!apexEvent.containsKey(fieldName)) { + if (!eventField.getOptional()) { + final String errorMessage = "error parsing " + eventDefinition.getID() + " event to Json. " + + "Field \"" + fieldName + "\" is missing, but is mandatory. Fields: " + apexEvent; + LOGGER.debug(errorMessage); + throw new ApexEventRuntimeException(errorMessage); + } + continue; + } + + final Object fieldValue = apexEvent.get(fieldName); + + // Get the schema helper + final SchemaHelper fieldSchemaHelper = + new SchemaHelperFactory().createSchemaHelper(eventField.getKey(), eventField.getSchema()); + jsonObject.add(fieldName, fieldSchemaHelper.marshal2JsonElement(fieldValue)); + } + + // Output JSON string in a pretty format + return gson.toJson(jsonObject); + } + + /** + * This method converts a JSON object into an Apex event. + * + * @param eventName the name of the event + * @param jsonEventString the JSON string that holds the event + * @return the apex event that we have converted the JSON object into + * @throws ApexEventException thrown on unmarshaling exceptions + */ + private ApexEvent jsonStringApexEvent(final String eventName, final String jsonEventString) + throws ApexEventException { + // Use GSON to read the event string + final JsonObject jsonObject = + new GsonBuilder().serializeNulls().create().fromJson(jsonEventString, JsonObject.class); + + if (jsonObject == null || !jsonObject.isJsonObject()) { + throw new ApexEventException( + "incoming event (" + jsonEventString + ") is not a JSON object or an JSON object array"); + } + + return jsonObject2ApexEvent(eventName, jsonObject); + } + + /** + * This method converts a JSON object into an Apex event. + * + * @param eventName the name of the event + * @param jsonObject the JSON object that holds the event + * @return the apex event that we have converted the JSON object into + * @throws ApexEventException thrown on unmarshaling exceptions + */ + private ApexEvent jsonObject2ApexEvent(final String eventName, final JsonObject jsonObject) + throws ApexEventException { + // Process the mandatory Apex header + final ApexEvent apexEvent = processApexEventHeader(eventName, jsonObject); + + // Get the event definition for the event from the model service + final AxEvent eventDefinition = + ModelService.getModel(AxEvents.class).get(apexEvent.getName(), apexEvent.getVersion()); + + // Iterate over the input fields in the event + for (final AxField eventField : eventDefinition.getFields()) { + final String fieldName = eventField.getKey().getLocalName(); + if (!hasJSONField(jsonObject, fieldName)) { + if (!eventField.getOptional()) { + final String errorMessage = "error parsing " + eventDefinition.getID() + " event from Json. " + + "Field \"" + fieldName + "\" is missing, but is mandatory."; + LOGGER.debug(errorMessage); + throw new ApexEventException(errorMessage); + } + continue; + } + + final JsonElement fieldValue = getJSONField(jsonObject, fieldName, null, !eventField.getOptional()); + + if (fieldValue != null && !fieldValue.isJsonNull()) { + // Get the schema helper + final SchemaHelper fieldSchemaHelper = + new SchemaHelperFactory().createSchemaHelper(eventField.getKey(), eventField.getSchema()); + apexEvent.put(fieldName, fieldSchemaHelper.createNewInstance(fieldValue)); + } else { + apexEvent.put(fieldName, null); + } + } + return apexEvent; + + } + + /** + * This method processes the event header of an Apex event. + * + * @param eventName the name of the event + * @param jsonObject the JSON object containing the JSON representation of the incoming event + * @return an apex event constructed using the header fields of the event + * @throws ApexEventRuntimeException the apex event runtime exception + * @throws ApexEventException on invalid events with missing header fields + */ + private ApexEvent processApexEventHeader(final String eventName, final JsonObject jsonObject) + throws ApexEventRuntimeException, ApexEventException { + // Get the event header fields + // @formatter:off + String name = getJSONStringField(jsonObject, ApexEvent.NAME_HEADER_FIELD, jsonPars.getNameAlias(), ApexEvent.NAME_REGEXP, false); + String version = getJSONStringField(jsonObject, ApexEvent.VERSION_HEADER_FIELD, jsonPars.getVersionAlias(), ApexEvent.VERSION_REGEXP, false); + String namespace = getJSONStringField(jsonObject, ApexEvent.NAMESPACE_HEADER_FIELD, jsonPars.getNameSpaceAlias(), ApexEvent.NAMESPACE_REGEXP, false); + String source = getJSONStringField(jsonObject, ApexEvent.SOURCE_HEADER_FIELD, jsonPars.getSourceAlias(), ApexEvent.SOURCE_REGEXP, false); + String target = getJSONStringField(jsonObject, ApexEvent.TARGET_HEADER_FIELD, jsonPars.getTargetAlias(), ApexEvent.TARGET_REGEXP, false); + // @formatter:on + + // Check if an event name was specified on the event parameters + if (eventName != null) { + if (name != null && !eventName.equals(name)) { + LOGGER.warn("The incoming event name \"" + name + "\" does not match the configured event name \"" + + eventName + "\", using configured event name"); + } + name = eventName; + } else { + if (name == null) { + throw new ApexEventRuntimeException( + "event received without mandatory parameter \"name\" on configuration or on event"); + } + } + + // Now, find the event definition in the model service. If version is null, the newest event + // definition in the model service is used + final AxEvent eventDefinition = ModelService.getModel(AxEvents.class).get(name, version); + if (eventDefinition == null) { + if (version == null) { + throw new ApexEventRuntimeException( + "an event definition for an event named \"" + name + "\" not found in Apex model"); + } else { + throw new ApexEventRuntimeException("an event definition for an event named \"" + name + + "\" with version \"" + version + "\" not found in Apex model"); + } + } + + // Use the defined event version if no version is specified on the incoming fields + if (version == null) { + version = eventDefinition.getKey().getVersion(); + } + + // Check the name space is OK if it is defined, if not, use the name space from the model + if (namespace != null) { + if (!namespace.equals(eventDefinition.getNameSpace())) { + throw new ApexEventRuntimeException( + "namespace \"" + namespace + "\" on event \"" + name + "\" does not match namespace \"" + + eventDefinition.getNameSpace() + "\" for that event in the Apex model"); + } + } else { + namespace = eventDefinition.getNameSpace(); + } + + // For source, use the defined source only if the source is not found on the incoming event + if (source == null) { + source = eventDefinition.getSource(); + } + + // For target, use the defined source only if the source is not found on the incoming event + if (target == null) { + target = eventDefinition.getTarget(); + } + + return new ApexEvent(name, version, namespace, source, target); + } + + /** + * This method gets an event string field from a JSON object. + * + * @param jsonObject the JSON object containing the JSON representation of the incoming event + * @param fieldName the field name to find in the event + * @param fieldAlias the alias for the field to find in the event, overrides the field name if + * it is not null + * @param fieldRE the regular expression to check the field against for validity + * @param mandatory true if the field is mandatory + * @return the value of the field in the JSON object or null if the field is optional + * @throws ApexEventRuntimeException the apex event runtime exception + */ + private String getJSONStringField(final JsonObject jsonObject, final String fieldName, final String fieldAlias, + final String fieldRE, final boolean mandatory) throws ApexEventRuntimeException { + // Get the JSON field for the string field + final JsonElement jsonField = getJSONField(jsonObject, fieldName, fieldAlias, mandatory); + + // Null strings are allowed + if (jsonField == null || jsonField.isJsonNull()) { + return null; + } + + // Check if this is a string field + String fieldValueString = null; + try { + fieldValueString = jsonField.getAsString(); + } catch (final Exception e) { + // The element is not a string so throw an error + throw new ApexEventRuntimeException("field \"" + fieldName + "\" with type \"" + + jsonField.getClass().getCanonicalName() + "\" is not a string value"); + } + + // Is regular expression checking required + if (fieldRE == null) { + return fieldValueString; + } + + // Check the event field against its regular expression + if (!fieldValueString.matches(fieldRE)) { + throw new ApexEventRuntimeException( + "field \"" + fieldName + "\" with value \"" + fieldValueString + "\" is invalid"); + } + + return fieldValueString; + } + + /** + * This method gets an event field from a JSON object. + * + * @param jsonObject the JSON object containing the JSON representation of the incoming event + * @param fieldName the field name to find in the event + * @param fieldAlias the alias for the field to find in the event, overrides the field name if + * it is not null + * @param mandatory true if the field is mandatory + * @return the value of the field in the JSON object or null if the field is optional + * @throws ApexEventRuntimeException the apex event runtime exception + */ + private JsonElement getJSONField(final JsonObject jsonObject, final String fieldName, final String fieldAlias, + final boolean mandatory) throws ApexEventRuntimeException { + + // Check if we should use the alias for this field + String fieldToFind = fieldName; + if (fieldAlias != null) { + fieldToFind = fieldAlias; + } + + // Get the event field + final JsonElement eventElement = jsonObject.get(fieldToFind); + if (eventElement == null) { + if (!mandatory) { + return null; + } else { + throw new ApexEventRuntimeException("mandatory field \"" + fieldToFind + "\" is missing"); + } + } + + return eventElement; + } + + /** + * This method if a JSON object has a named field. + * + * @param jsonObject the JSON object containing the JSON representation of the incoming event + * @param fieldName the field name to find in the event + * @return true if the field is present + * @throws ApexEventRuntimeException the apex event runtime exception + */ + private boolean hasJSONField(final JsonObject jsonObject, final String fieldName) throws ApexEventRuntimeException { + // check for the field + return jsonObject.has(fieldName); + } +} |