io.ebean.enhance.entity.ClassPathClassBytesReader Maven / Gradle / Ivy

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package io.ebean.enhance.entity;

import io.ebean.enhance.common.ClassBytesReader;
import io.ebean.enhance.common.InputStreamTransform;
import io.ebean.enhance.common.UrlHelper;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * Implementation of ClassBytesReader based on URLClassLoader.
 */
public class ClassPathClassBytesReader implements ClassBytesReader {

  private final URL[] urls;

  public ClassPathClassBytesReader(URL[] urls) {
    this.urls = urls == null ? new URL[0] : urls;
  }

  @Override
  public byte[] getClassBytes(String className, ClassLoader classLoader) {
    try (URLClassLoader cl = new URLClassLoader(urls, classLoader)) {
      String resource = className.replace('.', '/') + ".class";
      URL url = cl.getResource(resource);
      if (url == null) {
        return null;
      }

      try (InputStream is = UrlHelper.openNoCache(url)) {
        return InputStreamTransform.readBytes(is);

      } catch (IOException e) {
        throw new RuntimeException("IOException reading bytes for " + className, e);
      }
    } catch (IOException e) {
      throw new RuntimeException("Error closing URLClassLoader for " + className, e);
    }
  }

}