Java tutorial
/* * Copyright (C) 2012 Facebook, Inc. * * 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 com.facebook.swift.generator; import com.facebook.swift.generator.util.TemplateLoader; import com.facebook.swift.generator.visitors.ExceptionVisitor; import com.facebook.swift.generator.visitors.IntegerEnumVisitor; import com.facebook.swift.generator.visitors.ServiceVisitor; import com.facebook.swift.generator.visitors.StringEnumVisitor; import com.facebook.swift.generator.visitors.StructVisitor; import com.facebook.swift.generator.visitors.TypeVisitor; import com.facebook.swift.parser.model.Document; import com.facebook.swift.parser.model.Header; import com.facebook.swift.parser.visitor.DocumentVisitor; import com.google.common.base.Objects; import com.google.common.base.Preconditions; import com.google.common.base.Splitter; import com.google.common.collect.ImmutableMap; import com.google.common.collect.Iterables; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.File; import java.io.IOException; import java.net.URI; import java.util.List; import java.util.Map; import javax.annotation.Nullable; import static com.facebook.swift.generator.util.SwiftInternalStringUtils.isBlank; /** * Parses a Thrift IDL file and writes out initial annotated java classes. */ public class SwiftGenerator { private static final Logger LOG = LoggerFactory.getLogger(SwiftGenerator.class); private static final Map<String, String> TEMPLATES = ImmutableMap.of("java-regular", "java/regular.st", "java-immutable", "java/immutable.st"); private final File outputFolder; private final SwiftGeneratorConfig swiftGeneratorConfig; private final TemplateLoader templateLoader; public SwiftGenerator(final SwiftGeneratorConfig swiftGeneratorConfig) { Preconditions.checkState(TEMPLATES.get(swiftGeneratorConfig.getCodeFlavor()) != null, "Templating type %s is unknown!", swiftGeneratorConfig.getCodeFlavor()); this.swiftGeneratorConfig = swiftGeneratorConfig; this.outputFolder = swiftGeneratorConfig.getOutputFolder(); if (outputFolder != null) { outputFolder.mkdirs(); } LOG.debug("Writing source files into {} using {} ...", outputFolder, swiftGeneratorConfig.getCodeFlavor()); this.templateLoader = new TemplateLoader(TEMPLATES.get(swiftGeneratorConfig.getCodeFlavor())); } public void parse() throws Exception { LOG.info("Parsing Thrift IDL from {}...", swiftGeneratorConfig.getInputs()); final Map<String, SwiftDocumentContext> contexts = Maps.newHashMap(); for (final URI inputUri : swiftGeneratorConfig.getInputs()) { parseDocument(inputUri.isAbsolute() ? inputUri : swiftGeneratorConfig.getInputBase().resolve(inputUri), contexts, new TypeRegistry(), new TypedefRegistry()); } LOG.info("IDL parsing complete, writing java code..."); for (final SwiftDocumentContext context : contexts.values()) { generateFiles(context); } LOG.info("Java code generation complete."); } private void parseDocument(final URI thriftUri, @Nullable final Map<String, SwiftDocumentContext> contexts, final TypeRegistry typeRegistry, final TypedefRegistry typedefRegistry) throws IOException { Preconditions.checkState(thriftUri != null && thriftUri.isAbsolute() && !thriftUri.isOpaque(), "Only absolute, non opaque URIs can be parsed!"); LOG.debug("Parsing {}...", thriftUri); final String thriftNamespace = extractThriftNamespace(thriftUri); Preconditions.checkState(!isBlank(thriftNamespace), "Thrift URI %s can not be translated to a namespace", thriftUri); final SwiftDocumentContext context = new SwiftDocumentContext(thriftUri, thriftNamespace, swiftGeneratorConfig, typeRegistry, typedefRegistry); final Document document = context.getDocument(); final Header header = document.getHeader(); final String javaNamespace = Objects.firstNonNull( Objects.firstNonNull(swiftGeneratorConfig.getOverridePackage(), header.getNamespace("java")), swiftGeneratorConfig.getDefaultPackage()); Preconditions.checkState(!isBlank(javaNamespace), "thrift uri %s does not declare a java namespace!", thriftUri); for (final String include : header.getIncludes()) { final URI includeUri = swiftGeneratorConfig.getInputBase().resolve(include); LOG.debug("Found {} included from {}.", includeUri, thriftUri); parseDocument(includeUri, // If the includes should also generate code, pass the list of // contexts down to the include parser, otherwise pass a null in swiftGeneratorConfig.isGenerateIncludedCode() ? contexts : null, typeRegistry, typedefRegistry); } document.visit(new TypeVisitor(javaNamespace, context)); if (contexts != null && contexts.put(context.getNamespace(), context) != null) { LOG.info("Thrift Namespace {} included multiple times!", context.getNamespace()); } } private String extractThriftNamespace(final URI thriftUri) { final String path = thriftUri.getPath(); final String filename = Iterables.getLast(Splitter.on('/').split(path), null); Preconditions.checkState(filename != null, "No thrift namespace found in %s", thriftUri); final String name = Iterables.getFirst(Splitter.on('.').split(filename), null); Preconditions.checkState(name != null, "No thrift namespace found in %s", thriftUri); return name; } private void generateFiles(final SwiftDocumentContext context) throws IOException { LOG.debug("Generating code for {}...", context.getNamespace()); Preconditions.checkState(outputFolder != null, "The output folder was not set!"); Preconditions.checkState(outputFolder.isDirectory() && outputFolder.canWrite() && outputFolder.canExecute(), "output folder '%s' is not valid!", outputFolder.getAbsolutePath()); final List<DocumentVisitor> visitors = Lists.newArrayList(); visitors.add(new ServiceVisitor(templateLoader, context, swiftGeneratorConfig, outputFolder)); visitors.add(new StructVisitor(templateLoader, context, swiftGeneratorConfig, outputFolder)); visitors.add(new ExceptionVisitor(templateLoader, context, swiftGeneratorConfig, outputFolder)); visitors.add(new IntegerEnumVisitor(templateLoader, context, swiftGeneratorConfig, outputFolder)); visitors.add(new StringEnumVisitor(templateLoader, context, swiftGeneratorConfig, outputFolder)); for (DocumentVisitor visitor : visitors) { context.getDocument().visit(visitor); } } }