hex.tree.xgboost.util.NativeLibraryLoaderChain Maven / Gradle / Ivy

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/*
 Copyright (c) 2014 by Contributors

 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.
 */
package hex.tree.xgboost.util;

import java.io.IOException;
import java.util.LinkedList;

import ai.h2o.xgboost4j.java.INativeLibLoader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import static hex.tree.xgboost.util.NativeLibrary.CompilationFlags.WITH_GPU;
import static hex.tree.xgboost.util.NativeLibrary.CompilationFlags.WITH_OMP;
import static hex.tree.xgboost.util.NativeLibrary.EMPTY_COMPILATION_FLAGS;
import static hex.tree.xgboost.util.NativeLibrary.nativeLibrary;

/**
 * A simple loader which tries to load all
 * specified libraries in a given order.
 */
public class NativeLibraryLoaderChain implements INativeLibLoader {

  private static final Log logger = LogFactory.getLog(NativeLibraryLoaderChain.class);

  private final NativeLibrary[] nativeLibs;

  private NativeLibrary successfullyLoaded = null;

  @SuppressWarnings("unused")
  public NativeLibraryLoaderChain() {
    this(
      // GPU & OpenMP support enabled - backend will be decided at runtime based on availability
      nativeLibrary("xgboost4j_gpu", new NativeLibrary.CompilationFlags[] {WITH_GPU, WITH_OMP}),
      // Minimum version of library - no gpu, no omp
      nativeLibrary("xgboost4j_minimal", EMPTY_COMPILATION_FLAGS)
    );
  }

  private NativeLibraryLoaderChain(NativeLibrary... libs) {
    assert libs != null : "Argument `libs` cannot be null.";
    nativeLibs = libs;
  }

  public NativeLibrary[] getNativeLibs() {
    return nativeLibs;
  }
  
  @Override
  public void loadNativeLibs() throws IOException {
    LinkedList exs = new LinkedList<>();
    for (NativeLibrary lib : nativeLibs) {
      try {
        // Try to load
        if (lib.load()) {
          // It was successful load, so remember it
          successfullyLoaded = lib;
          break;
        }
      } catch (IOException e) {
        logger.info("Cannot load library: " + lib.toString());
        exs.add(e);
      }
    }
    if ((successfullyLoaded == null) && (! exs.isEmpty())) {
      throw new IOException(exs.getLast());
    }
  }

  @Override
  public String name() {
    return "NativeLibraryLoaderChain";
  }

  @Override
  public int priority() {
    return 1;
  }

  public NativeLibrary getLoadedLibrary() throws IOException {
    if (successfullyLoaded != null) {
      return successfullyLoaded;
    } else {
      throw new IOException("No binary library found!");
    }
  }

}