UrlZipExplorer.java

package org.batfish.common.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class UrlZipExplorer {

   private Set<String> _entries;
   private ZipInputStream _stream;
   private URL _url;

   public UrlZipExplorer(URL url) throws IOException {
      _url = url;
      _entries = new LinkedHashSet<>();
      initListing();
   }

   public void extractFiles(StringFilter filter, File destinationDir)
         throws IOException {
      _stream = new ZipInputStream(_url.openStream());
      ZipEntry ze = null;
      while ((ze = _stream.getNextEntry()) != null) {
         String entryName = ze.getName();
         if (filter.accept(entryName)) {
            Path dstPath = Paths.get(destinationDir.getAbsolutePath(),
                  entryName);
            File parentDir = dstPath.toFile().getParentFile();
            parentDir.mkdirs();
            Files.copy(_stream, dstPath);
         }
      }
   }

   public InputStream getInputStream() {
      return _stream;
   }

   private void initListing() throws IOException {
      _stream = new ZipInputStream(_url.openStream());
      ZipEntry ze = null;
      while ((ze = _stream.getNextEntry()) != null) {
         String entryName = ze.getName();
         _entries.add(entryName);
      }
      _stream.close();
   }

   public Set<String> listFiles(StringFilter filter) {
      Set<String> matches = new LinkedHashSet<>();
      for (String entry : _entries) {
         if (filter.accept(entry)) {
            matches.add(entry);
         }
      }
      return matches;
   }

   public void openFile(String name) throws IOException {
      _stream = new ZipInputStream(_url.openStream());
      ZipEntry ze = null;
      while ((ze = _stream.getNextEntry()) != null) {
         String entryName = ze.getName();
         if (entryName.equals(name)) {
            return;
         }
      }
      throw new FileNotFoundException(name);
   }
}