DtoFactoryVisitorRegistryGenerator.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.util;

import org.apache.commons.io.FileUtils;
import org.eclipse.che.ide.dto.ClientDtoFactoryVisitor;
import org.reflections.Reflections;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import static org.eclipse.che.util.IgnoreUnExistedResourcesReflectionConfigurationBuilder.*;

/**
 * Generates {DtoFactoryVisitorRegistry} class source.
 *
 * @author Artem Zatsarynnyi
 */
public class DtoFactoryVisitorRegistryGenerator {

    /**
     * Path of the output class, it definitely should already exits. To ensure proper config.
     * File content will be overridden.
     */
    protected static final String              REGISTRY_PATH      =
            "org/eclipse/che/ide/client/DtoFactoryVisitorRegistry.java";
    /** Map containing <FullFQN, ClassName> */
    protected static final Map<String, String> dtoFactoryVisitors = new HashMap<>();

    /**
     * Entry point. --rootDir is the optional parameter.
     *
     * @param args
     * @throws IOException 
     */
    public static void main(String[] args) throws IOException {
        File rootFolder = GeneratorUtils.getRootFolder(args);
        System.out.println(" ------------------------------------------------------------------------ ");
        System.out.println("Searching for DTO");
        System.out.println(" ------------------------------------------------------------------------ ");

        // find all DtoFactoryVisitors
        findDtoFactoryVisitors();
        generateExtensionManager(rootFolder);
    }

    /**
     * Find all the Java classes that have proper @ClientDtoFactoryVisitor annotation.
     *
     * @throws java.io.IOException
     */
    @SuppressWarnings("unchecked")
    private static void findDtoFactoryVisitors() throws IOException {
        Reflections reflection = new Reflections(getConfigurationBuilder());
        Set<Class<?>> classes = reflection.getTypesAnnotatedWith(ClientDtoFactoryVisitor.class);
        int i = 0;
        for (Class clazz : classes) {
            dtoFactoryVisitors.put(clazz.getCanonicalName(), "provider_" + i++);
            System.out.println(String.format("New DtoFactoryVisitor found: %s", clazz.getCanonicalName()));
        }
        System.out.println(String.format("Found: %d DtoFactoryVisitor(s)", dtoFactoryVisitors.size()));
    }

    /**
     * Generate to source of the class.
     *
     * @param rootFolder
     */
    public static void generateExtensionManager(File rootFolder) throws IOException {
        File outFile = new File(rootFolder, REGISTRY_PATH);

        StringBuilder builder = new StringBuilder();
        builder.append("package org.eclipse.che.ide.client;\n\n");
        generateImports(builder);
        generateClass(builder);

        // flush content
        FileUtils.writeStringToFile(outFile, builder.toString());
    }

    /**
     * Generate imports.
     *
     * @param builder
     */
    public static void generateImports(StringBuilder builder) {
        builder.append("import com.google.inject.Inject;\n");
        builder.append("import com.google.inject.Provider;\n");
        builder.append("import com.google.inject.Singleton;\n");

        builder.append("import java.util.HashMap;\n");
        builder.append("import java.util.Map;\n");
    }

    /**
     * Generate class declarations.
     *
     * @param builder
     */
    public static void generateClass(StringBuilder builder) {
        // generate class header
        builder.append("/**\n");
        builder.append(" * THIS CLASS WILL BE OVERRIDDEN BY MAVEN BUILD. DON'T EDIT CLASS, IT WILL HAVE NO EFFECT.\n");
        builder.append(" */\n");
        builder.append("@Singleton\n");
        builder.append("@SuppressWarnings(\"rawtypes\")\n");
        builder.append("public class DtoFactoryVisitorRegistry\n");
        builder.append("{\n");
        builder.append("\n");

        // field
        builder.append(GeneratorUtils.TAB)
               .append("/** Contains the map with all the DtoFactoryVisitor Providers <FullClassFQN, Provider>. */\n");
        builder.append(GeneratorUtils.TAB).append("protected final Map<String, Provider> providers = new HashMap<>();\n\n");

        // generate constructor
        builder.append(GeneratorUtils.TAB).append("/** Constructor that accepts all found DtoFactoryVisitor Providers. */\n");
        builder.append(GeneratorUtils.TAB).append("@Inject\n");
        builder.append(GeneratorUtils.TAB).append("public DtoFactoryVisitorRegistry(\n");

        // paste args here
        Iterator<Entry<String, String>> entryIterator = dtoFactoryVisitors.entrySet().iterator();
        while (entryIterator.hasNext()) {
            // <FullFQN, ClassName>
            Entry<String, String> entry = entryIterator.next();
            String hasComma = entryIterator.hasNext() ? "," : "";
            // add constructor argument like:
            // fullFQN classNameToLowerCase,
            String classFQN = String.format("Provider<%s>", entry.getKey());
            String variableName = entry.getValue().toLowerCase();
            builder.append(GeneratorUtils.TAB2).append(classFQN).append(" ").append(variableName).append(hasComma).append("\n");
        }

        builder.append(GeneratorUtils.TAB).append(")\n");
        builder.append(GeneratorUtils.TAB).append("{\n");

        // paste add here
        for (Entry<String, String> entries : dtoFactoryVisitors.entrySet()) {
            String fullFqn = entries.getKey();
            String variableName = entries.getValue().toLowerCase();

            String putStatement = String.format("this.providers.put(\"%s\", %s);%n", fullFqn, variableName);
            builder.append(GeneratorUtils.TAB2).append(putStatement);
        }

        // close constructor
        builder.append(GeneratorUtils.TAB).append("}\n\n");

        // generate getter
        builder.append(GeneratorUtils.TAB)
               .append("/** Returns the map with all the DtoFactoryVisitor Providers <FullClassFQN, Provider>. */\n");
        builder.append(GeneratorUtils.TAB).append("public Map<String, Provider> getDtoFactoryVisitors()\n");
        builder.append(GeneratorUtils.TAB).append("{\n");
        builder.append(GeneratorUtils.TAB2).append("return providers;\n");
        builder.append(GeneratorUtils.TAB).append("}\n");

        // close class
        builder.append("}\n");
    }
}