Java tutorial
/** * Copyright 2005-2016 Red Hat, Inc. * * Red Hat licenses this file to you 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 io.fabric8.kubernetes.generator.processor; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; import io.fabric8.kubernetes.api.KubernetesHelper; import io.fabric8.kubernetes.api.model.KubernetesResource; import javax.annotation.processing.AbstractProcessor; import javax.lang.model.element.Element; import javax.lang.model.element.PackageElement; import javax.lang.model.element.TypeElement; import javax.tools.Diagnostic; import javax.tools.FileObject; import javax.tools.StandardLocation; import java.io.File; import java.io.IOException; import java.io.Reader; import java.io.Writer; import java.nio.file.Path; import java.nio.file.Paths; public abstract class AbstractKubernetesAnnotationProcessor extends AbstractProcessor { private static final String KUBERNETES_JSON = "kubernetes.json"; private static final String KUBERNETES_YAML = "kubernetes.yml"; private static final ObjectMapper MAPPER = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT); enum FileExtension { JSON, YAML, UNDEFINED; public static FileExtension determineExtension(String extension) { if ("json".equals(extension)) { return JSON; } else if ("yaml".equals(extension) || "yml".equals(extension)) { return YAML; } else { return UNDEFINED; } } } KubernetesResource readJson(String fileName) { try { FileObject fileObject = processingEnv.getFiler().getResource(StandardLocation.CLASS_OUTPUT, "", (fileName == null ? KUBERNETES_JSON : fileName)); try (Reader reader = fileObject.openReader(false)) { return MAPPER.readValue(reader, KubernetesResource.class); } } catch (IOException e) { processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, fileName + " JSON not found."); } return null; } void generateJson(KubernetesResource resource) { generateJson(KUBERNETES_JSON, resource); } void generateJson(String fileName, KubernetesResource resource) { try { FileObject fileObject = getFileObject(fileName); try (Writer writer = fileObject.openWriter()) { MAPPER.writeValue(writer, resource); } } catch (IOException e) { processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, "Error generating json " + fileName); } } void generateYaml(KubernetesResource resource) { generateYaml(KUBERNETES_YAML, resource); } void generateYaml(String fileName, KubernetesResource resource) { try { FileObject fileObject = getFileObject(fileName); KubernetesHelper.saveYaml(resource, fileObject); } catch (IOException e) { processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, "Error generating json " + fileName); } } private FileObject getFileObject(String fileName) throws IOException { FileObject fileObject = processingEnv.getFiler().getResource(StandardLocation.CLASS_OUTPUT, "", fileName); Path path = Paths.get(fileObject.toUri()); File file = path.toFile(); if (file.exists() && !file.delete()) { throw new IOException("Failed to delete old kubernetes json file: " + fileName); } fileObject = processingEnv.getFiler().createResource(StandardLocation.CLASS_OUTPUT, "", fileName); return fileObject; } TypeElement getClassElement(Element element) { if (element instanceof PackageElement) { throw new IllegalArgumentException( "Invalid element. A package element can't be used to retrieve a class element"); } else if (element instanceof TypeElement && element.getEnclosingElement() instanceof PackageElement) { return (TypeElement) element; } else { return getClassElement(element.getEnclosingElement()); } } PackageElement getPackageElement(Element element) { if (element instanceof PackageElement) { return (PackageElement) element; } else { return getPackageElement(element.getEnclosingElement()); } } }