JarBuilder.java

/*
 * #%L
 * restdoc-plugin
 * %%
 * Copyright (C) 2012 IG Group
 * %%
 * 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.
 * #L%
 */
package com.iggroup.oss.restdoclet.plugin.io;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;

import org.apache.log4j.Logger;

import com.iggroup.oss.restdoclet.plugin.util.MavenUtils;

/**
 * Assembles the web-application generated by documentation.
 */
public class JarBuilder {

   private static final Logger LOG = Logger.getLogger(JarBuilder.class);

   /**
    * The name of the manifest-file.
    */
   public static final String MANIFEST = "MANIFEST.MF";

   /**
    * The path-separator while building the archive.
    */
   public static final char SEP = '/';

   /**
    * The <code>target</code> directories of the module RestDocumentationMojo
    * is running on.
    */
   private final transient DirectoryBuilder dirs;

   /**
    * The name of the archive the web-application is assembled as. This name
    * includes the classifier used while running RestDocumentationMojo.
    */
   private transient String finalName;

   /**
    * Constructs this builder with the <code>target</code> directories of the
    * module RestDocumentationMojo is running on and the name of the archive
    * the web-application has to be assembled as.
    * 
    * @param dirs the <code>target</code> directories.
    * @param finalName the name of the archive.
    */
   public JarBuilder(final DirectoryBuilder dirs, final String finalName) {
      this.dirs = dirs;
      initFinalName(finalName);
   }

   /**
    * Initialises the name of the archive the web-application has to be
    * assembled as.
    * 
    * @param finalName the name of the archive.
    */
   private void initFinalName(final String finalName) {
      final String suffix = '.' + MavenUtils.JAR_PACKAGING;
      if (finalName.endsWith(suffix)) {
         this.finalName = finalName;
      } else {
         this.finalName = finalName + suffix;
      }
   }

   /**
    * Creates the manifest-file.
    * 
    * @return the manifest-file.
    * @throws IOException if the manifest-file can't be read.
    */
   private Manifest createManifest() throws IOException {
      return new Manifest(getClass().getResourceAsStream(MANIFEST));
   }

   /**
    * Puts an entry in the JAR's output-stream.
    * 
    * @param jos the JAR's output-stream.
    * @param name the name of the entry.
    * @param file the file containing the entry's contents.
    * @throws IOException if the file can't be copied.
    */
   private void putEntry(final JarOutputStream jos, final String name,
                         final File file) throws IOException {
      /* add entry */
      final JarEntry entry = new JarEntry(name);
      jos.putNextEntry(entry);
      /* write contents */
      IOUtils.copy(file, jos);
   }

   /**
    * Puts the classpath entries in the JAR's output-stream.
    * 
    * @param jos the JAR's output-stream.
    * @throws IOException if an entry can't be copied.
    */
   private void putResourceConfigs(final JarOutputStream jos)
      throws IOException {
      for (File file : dirs.getClassesDirectory().listFiles()) {
         if (file.isFile()) {
            LOG.debug("Adding " + file);
            final String name = file.getName();
            putEntry(jos, name, file);
         }
      }
   }

   /**
    * Assembles the jar .
    * 
    * @return the assembled jar
    * @throws IOException if the jar can't be created or a JAR's entry can't be
    *            copied.
    */
   public File build() throws IOException {
      /* jar output stream */
      final File jar = new File(dirs.getTargetDirectory(), finalName);
      LOG.info("Building " + jar);
      final JarOutputStream jos =
         new JarOutputStream(new BufferedOutputStream(
            new FileOutputStream(jar)), createManifest());
      putResourceConfigs(jos);
      jos.close();
      return jar;
   }

}