uk.co.unclealex.executable.generator.CodeGeneratorImpl.java Source code

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Here is the source code for uk.co.unclealex.executable.generator.CodeGeneratorImpl.java

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/**
 * Copyright 2012 Alex Jones
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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 uk.co.unclealex.executable.generator;

import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.Path;
import java.util.List;
import java.util.Map;

import javax.inject.Inject;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import uk.co.unclealex.executable.Executable;
import uk.co.unclealex.executable.generator.model.ExecutableAnnotationInformation;
import uk.co.unclealex.executable.generator.scan.AllClassNamesCollector;
import uk.co.unclealex.executable.generator.scan.ExecutableAnnotationInformationFinder;
import uk.co.unclealex.executable.generator.scan.exception.ExecutableScanException;
import uk.co.unclealex.executable.generator.writer.GeneratedClassWriter;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

/**
 * The default implementation of {@link CodeGenerator}.
 * 
 * @author alex
 * 
 */
public class CodeGeneratorImpl implements CodeGenerator {

    /** The Constant log. */
    private static final Logger log = LoggerFactory.getLogger(CodeGeneratorImpl.class);

    /**
     * The {@link AllClassNamesCollector} used to find all the class names in the
     * source directory.
     */
    private final AllClassNamesCollector allClassNamesCollector;

    /**
     * The {@link ExecutableAnnotationInformationFinder} used to find all
     * {@link Executable} annotations.
     */
    private final ExecutableAnnotationInformationFinder executableAnnotationInformationFinder;

    /**
     * The {@link GeneratedClassWriter} used to write the generated classes to
     * disk.
     */
    private final GeneratedClassWriter generatedClassWriter;

    /**
     * Instantiates a new code generator impl.
     * 
     * @param allClassNamesCollector
     *          the all class names collector
     * @param executableAnnotationInformationFinder
     *          the executable annotation information finder
     * @param generatedClassWriter
     *          the generated class writer
     */
    @Inject
    public CodeGeneratorImpl(AllClassNamesCollector allClassNamesCollector,
            ExecutableAnnotationInformationFinder executableAnnotationInformationFinder,
            GeneratedClassWriter generatedClassWriter) {
        super();
        this.allClassNamesCollector = allClassNamesCollector;
        this.executableAnnotationInformationFinder = executableAnnotationInformationFinder;
        this.generatedClassWriter = generatedClassWriter;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void generate(ClassLoader classLoader, Path sourceDirectory, Path targetDirectory)
            throws IOException, ExecutableScanException {
        ClassLoader generatedClassLoader = new URLClassLoader(new URL[] { sourceDirectory.toUri().toURL() },
                classLoader);
        List<String> allClassNames = getAllClassNamesCollector().listAllClassNames(sourceDirectory);
        List<Class<?>> allClasses = Lists
                .newArrayList(Iterables.transform(allClassNames, new ClassFunction(generatedClassLoader)));
        List<ExecutableAnnotationInformation> executableAnnotationInformations = getExecutableAnnotationInformationFinder()
                .findExecutableAnnotationInformation(allClasses);
        log.info("Found the following scripts: " + Joiner.on(", ").join(
                Sets.newTreeSet(Iterables.transform(executableAnnotationInformations, new ScriptNameFunction()))));
        GeneratedClassWriter generatedClassWriter = getGeneratedClassWriter();
        Map<String, String> commandRunnerClassNamesByScriptName = Maps.newTreeMap();
        for (ExecutableAnnotationInformation executableAnnotationInformation : executableAnnotationInformations) {
            String commandRunnerClassName = generatedClassWriter
                    .writeClass(executableAnnotationInformation, generatedClassLoader, targetDirectory)
                    .getClassName();
            String scriptName = executableAnnotationInformation.getScriptName();
            commandRunnerClassNamesByScriptName.put(scriptName, commandRunnerClassName);
            log.info("Written class " + commandRunnerClassName + " for script " + scriptName);
        }
        generatedClassWriter.writeEntryPointClass(targetDirectory, commandRunnerClassNamesByScriptName);
    }

    /**
     * The Class ScriptNameFunction.
     */
    static class ScriptNameFunction implements Function<ExecutableAnnotationInformation, String> {

        /**
         * {@inheritDoc}
         */
        @Override
        public String apply(ExecutableAnnotationInformation executableAnnotationInformation) {
            return executableAnnotationInformation.getScriptName();
        }
    }

    /**
     * The Class ClassFunction.
     */
    static class ClassFunction implements Function<String, Class<?>> {

        /** The class loader. */
        private final ClassLoader classLoader;

        /**
         * Instantiates a new class function.
         * 
         * @param classLoader
         *          the class loader
         */
        public ClassFunction(ClassLoader classLoader) {
            super();
            this.classLoader = classLoader;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public Class<?> apply(String className) {
            try {
                return getClassLoader().loadClass(className);
            } catch (ClassNotFoundException e) {
                throw new IllegalStateException("Cannot find class " + className, e);
            }
        }

        /**
         * Gets the class loader.
         * 
         * @return the class loader
         */
        public ClassLoader getClassLoader() {
            return classLoader;
        }
    }

    /**
     * Gets the {@link AllClassNamesCollector} used to find all the class names in
     * the source directory.
     * 
     * @return the {@link AllClassNamesCollector} used to find all the class names
     *         in the source directory
     */
    public AllClassNamesCollector getAllClassNamesCollector() {
        return allClassNamesCollector;
    }

    /**
     * Gets the {@link ExecutableAnnotationInformationFinder} used to find all
     * {@link Executable} annotations.
     * 
     * @return the {@link ExecutableAnnotationInformationFinder} used to find all
     *         {@link Executable} annotations
     */
    public ExecutableAnnotationInformationFinder getExecutableAnnotationInformationFinder() {
        return executableAnnotationInformationFinder;
    }

    /**
     * Gets the {@link GeneratedClassWriter} used to write the generated classes
     * to disk.
     * 
     * @return the {@link GeneratedClassWriter} used to write the generated
     *         classes to disk
     */
    public GeneratedClassWriter getGeneratedClassWriter() {
        return generatedClassWriter;
    }

}