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Diffstat (limited to 'src/main/java/org/onap/aai/validation/modeldriven/ModelCacheManager.java')
| -rw-r--r-- | src/main/java/org/onap/aai/validation/modeldriven/ModelCacheManager.java | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/src/main/java/org/onap/aai/validation/modeldriven/ModelCacheManager.java b/src/main/java/org/onap/aai/validation/modeldriven/ModelCacheManager.java new file mode 100644 index 0000000..5c741fb --- /dev/null +++ b/src/main/java/org/onap/aai/validation/modeldriven/ModelCacheManager.java @@ -0,0 +1,182 @@ +/* + * ============LICENSE_START=================================================== + * Copyright (c) 2018 Amdocs + * ============================================================================ + * 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. + * ============LICENSE_END===================================================== + */ +package org.onap.aai.validation.modeldriven; + +import com.google.common.cache.CacheBuilder; +import com.google.common.cache.CacheLoader; +import com.google.common.cache.LoadingCache; +import java.io.File; +import java.net.URI; +import java.net.URISyntaxException; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.TimeUnit; +import javax.inject.Inject; +import javax.ws.rs.core.MediaType; +import org.apache.http.client.utils.URIBuilder; +import org.dom4j.Element; +import org.onap.aai.validation.config.ModelConfig; +import org.onap.aai.validation.config.RestConfig; +import org.onap.aai.validation.data.client.RestClient; +import org.onap.aai.validation.exception.ValidationServiceError; +import org.onap.aai.validation.exception.ValidationServiceException; +import org.onap.aai.validation.modeldriven.parser.XMLModelParser; + +/** + * A cache of model UUID against the parsed model Element, using Guava's CacheBuilder. + */ +public class ModelCacheManager { + + public static final String FILE_MODEL_PROTOCOL = "file"; + + private LoadingCache<ModelId, Element> modelCache; + private RestConfig restConfig; + + /** + * Initialises the instance by loading validator properties from config. + * + * @param modelConfig + * @param restConfig + * @throws ValidationServiceException + */ + @Inject + public ModelCacheManager(ModelConfig modelConfig, RestConfig restConfig) { + this.restConfig = restConfig; + + // Create an expiring cache with a load implementation which is executed when a key value is not cached. + modelCache = CacheBuilder.newBuilder().maximumSize(1000) + .expireAfterWrite(modelConfig.getModelCacheExpirySeconds(), TimeUnit.SECONDS) + .build(new CacheLoader<ModelId, Element>() { + @Override + public Element load(ModelId key) throws ValidationServiceException { + return retrieveModelElement(key); + } + }); + } + + /** + * Gets the model with specified uuid from the model cache. If model is not cached, retrieve the model from the + * external system. + * + * @param uuid + * The model UUID. + * @return The DOM Element representing the model's root element. + * @throws ValidationServiceException + */ + public Element get(ModelId uuid) throws ValidationServiceException { + if (uuid == null || uuid.isEmpty()) { + return null; + } + + return getCachedModel(uuid); + } + + private Element getCachedModel(ModelId uuid) throws ValidationServiceException { + Element element = null; + try { + element = modelCache.get(uuid); + } catch (ExecutionException e) { + // If the wrapped exception is a model validation error, return null. + Throwable cause = e.getCause(); + if (cause != null && cause.getClass().equals(ValidationServiceException.class) + && (((ValidationServiceException) cause).getId().equals(ValidationServiceError.MODEL_NOT_FOUND.getId()) + || ((ValidationServiceException) cause).getId().equals(ValidationServiceError.REST_CLIENT_RESPONSE_NOT_FOUND.getId()))) { + return null; + } + throw new ValidationServiceException(ValidationServiceError.MODEL_CACHE_ERROR, e, ""); + } + return element; + } + + /** + * Puts an item into the model cache. + * + * @param uuid + * The key. + * @param modelElement + * The value. + */ + public void put(ModelId uuid, Element modelElement) { + modelCache.put(uuid, modelElement); + } + + /** + * Constructs and invokes the configured REST URL. The XML payload is then parsed into a model Element. + * + * @param uuid + * The model UUID to retrieve. + * @return The payload of the REST URL call as a model Element. + * @throws ValidationServiceException + * if the payload is null + */ + private Element retrieveModelElement(ModelId uuid) throws ValidationServiceException { + String protocol = restConfig.getProtocol(); + Element modelElement; + if (FILE_MODEL_PROTOCOL.equals(protocol)) { + File modelFile = new File(restConfig.getBaseModelURI()); + modelElement = retrieveModelElementFromFile(modelFile, uuid); + } else { + modelElement = retrieveModelElementFromREST(restConfig, uuid); + } + + // Do not store a null value in the CacheBuilder + if (modelElement != null) { + return modelElement; + } else { + throw new ValidationServiceException(ValidationServiceError.MODEL_NOT_FOUND, uuid); + } + } + + /** + * Constructs and invokes the configured REST URL to retrieve the model for the supplied UUID. The XML payload is + * then parsed into a model Element. + * + * @param uuid + * The model UUID to retrieve. + * @return The payload of the REST URL call as a model Element, or null of no model could be found. + * @throws ValidationServiceException + */ + private Element retrieveModelElementFromREST(RestConfig restConfig, ModelId uuid) + throws ValidationServiceException { + try { + URI restURI = new URIBuilder(restConfig.getBaseModelURI()) + .addParameter(uuid.getModelIdAttribute(), uuid.getModelId()).build(); + String restPayload = new RestClient(restConfig).get(restURI.toString(), MediaType.APPLICATION_XML); + return XMLModelParser.parse(restPayload, true); + } catch (URISyntaxException e) { + throw new ValidationServiceException(ValidationServiceError.MODEL_RETRIEVAL_ERROR, e); + } + } + + /** + * Retrieves the model with supplied model UUID from the supplied model file. The XML payload is then parsed into a + * model Element. + * + * @param uuid + * The model UUID to retrieve. + * @return The model Element, or null if no model could be found. + * @throws ValidationServiceException + */ + private Element retrieveModelElementFromFile(File modelFile, ModelId uuid) throws ValidationServiceException { + Element rootElement = XMLModelParser.parse(modelFile, false); + // Check that the root element of the model file is correct. + if (!XMLModelParser.MODELS_ROOT_ELEMENT.equals(rootElement.getName())) { + return null; + } + return XMLModelParser.getModelElementWithId(rootElement, uuid.getModelIdAttribute(), uuid.getModelId()); + } +}
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