ml.dmlc.xgboost4j.java.NativeLibraryLoaderChain.java Source code

Introduction

Here is the source code for ml.dmlc.xgboost4j.java.NativeLibraryLoaderChain.java

Source

/*
 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 ml.dmlc.xgboost4j.java;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import static ml.dmlc.xgboost4j.java.NativeLibrary.CompilationFlags.WITH_GPU;
import static ml.dmlc.xgboost4j.java.NativeLibrary.CompilationFlags.WITH_OMP;
import static ml.dmlc.xgboost4j.java.NativeLibrary.EMPTY_COMPILATION_FLAGS;
import static ml.dmlc.xgboost4j.java.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 }),
                // OpenMP 3.x support enabled (when libgomp1 4.x is not available - eg. Ubuntu 14.04)
                nativeLibrary("xgboost4j_omp", new NativeLibrary.CompilationFlags[] { 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;
    }

    @Override
    public void loadNativeLibs() throws IOException {
        LinkedList<IOException> 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!");
        }
    }

}