content: /*
   *  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
   *
   *      https://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 org.apache.tools.ant.taskdefs.optional.depend;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipInputStream;
  
  import org.apache.tools.ant.BuildException;
  
  /**
   * A class file iterator which iterates through the contents of a Java jar
   * file.
   *
   */
  public class JarFileIterator implements ClassFileIterator {
      /** The jar stream from the jar file being iterated over*/
      private ZipInputStream jarStream;
  
      /**
       * Construct an iterator over a jar stream
       *
       * @param stream the basic input stream from which the Jar is received
       * @exception IOException if the jar stream cannot be created
       */
      public JarFileIterator(InputStream stream) throws IOException {
          super();
          jarStream = new ZipInputStream(stream);
      }
  
      /**
       * Get the next ClassFile object from the jar
       *
       * @return a ClassFile object describing the class from the jar
       */
      @Override
      public ClassFile getNextClassFile() {
          ZipEntry jarEntry;
          ClassFile nextElement = null;
  
          try {
              jarEntry = jarStream.getNextEntry();
  
              while (nextElement == null && jarEntry != null) {
                  String entryName = jarEntry.getName();
  
                  if (!jarEntry.isDirectory() && entryName.endsWith(".class")) {
  
                      // create a data input stream from the jar input stream
                      ClassFile javaClass = new ClassFile();
  
                      javaClass.read(jarStream);
  
                      nextElement = javaClass;
                  } else {
                      jarEntry = jarStream.getNextEntry();
                  }
              }
          } catch (IOException e) {
              String message = e.getMessage();
              String text = e.getClass().getName();
  
              if (message != null) {
                  text += ": " + message;
              }
  
              throw new BuildException("Problem reading JAR file: " + text);
          }
          return nextElement;
      }
  
  }
  