org.smallmind.spark.singularity.boot.CachedJarFile Maven / Gradle / Ivy

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/*
 * Copyright (c) 2007 through 2024 David Berkman
 *
 * This file is part of the SmallMind Code Project.
 *
 * The SmallMind Code Project is free software, you can redistribute
 * it and/or modify it under either, at your discretion...
 *
 * 1) The terms of GNU Affero General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * ...or...
 *
 * 2) The terms of the Apache License, Version 2.0.
 *
 * The SmallMind Code Project is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License or Apache License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * and the Apache License along with the SmallMind Code Project. If not, see
 *  or .
 *
 * Additional permission under the GNU Affero GPL version 3 section 7
 * ------------------------------------------------------------------
 * If you modify this Program, or any covered work, by linking or
 * combining it with other code, such other code is not for that reason
 * alone subject to any of the requirements of the GNU Affero GPL
 * version 3.
 */
package org.smallmind.spark.singularity.boot;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;

public class CachedJarFile {

  private final HashMap entryMap = new HashMap<>();
  private final String entryName;

  public CachedJarFile (String entryName, JarInputStream jarInputStream)
    throws IOException {

    JarEntry innerJarEntry;
    byte[] buffer = new byte[8192];

    this.entryName = entryName;

    while ((innerJarEntry = jarInputStream.getNextJarEntry()) != null) {

      int bytesRead;

      try (ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream()) {
        while ((bytesRead = jarInputStream.read(buffer)) >= 0) {
          byteOutputStream.write(buffer, 0, bytesRead);
        }

        entryMap.put(innerJarEntry.getName(), byteOutputStream.toByteArray());
      }
    }
  }

  public String getEntryName () {

    return entryName;
  }

  public InputStream getInputStream (String name) {

    byte[] contents;

    if ((contents = entryMap.get(name)) != null) {

      return new ByteArrayInputStream(contents);
    }

    return null;
  }
}