import com.google.code.externalsorting.ExternalSort; //导入依赖的package包/类
public static File sortFile(String inputFile, String outputFile, Comparator<String> comparator) throws IOException {

		File file;
		List<File> files;

		files = ExternalSort.sortInBatch(new File(inputFile));
		file = new File(outputFile);
		ExternalSort.mergeSortedFiles(files, file, comparator);

		return file;
	}
 

import com.google.code.externalsorting.ExternalSort; //导入依赖的package包/类
public static void externalSort(File srcFile, File destFile, Comparator<String> comparator) throws IOException {

		File tmpDir = destFile.getParentFile();
		List<File> tmpFiles = ExternalSort.sortInBatch(srcFile, comparator, 4096, Charset.defaultCharset(), tmpDir,
				false);
		ExternalSort.mergeSortedFiles(tmpFiles, destFile, comparator);

	}
 

import com.google.code.externalsorting.ExternalSort; //导入依赖的package包/类
/**
 * Calculates maximum memory limit available for data structures.
 * @return memory limit in bytes
 */
protected long calculateMemoryLimit() {
    return Math.min(
            config.getMemoryLimit() != null ? config.getMemoryLimit() : Long.MAX_VALUE,
            (long) (ExternalSort.estimateAvailableMemory() * config.getMaxFreeMemoryUsage()));
}
 

import com.google.code.externalsorting.ExternalSort; //导入依赖的package包/类
public static DiskDGraph fromFile(File file, File tmpDir, File dbFile)
		throws IOException
	{
	DiskDGraph graph = new DiskDGraph(dbFile, true);

	// * sort the input file by first element
       File forward = new File(tmpDir, "forward.edgelist");
       
       
       List<File> files = ExternalSort.sortInBatch(
       		file, 
       		new LComp(true), ExternalSort.DEFAULTMAXTEMPFILES, 
       		Charset.defaultCharset(), tmpDir, false);
       ExternalSort.mergeSortedFiles(files, forward, new LComp(true), Charset.defaultCharset());
       
       System.out.println("Forward sort finished");
       
       readSorted(graph.out, forward, true);
       
       System.out.println("Forward list read");

       forward.delete();
       File backward = new File(tmpDir, "backward.edgelist");
       
       files = ExternalSort.sortInBatch(
       		file, 
       		new LComp(false), ExternalSort.DEFAULTMAXTEMPFILES, 
       		Charset.defaultCharset(), tmpDir, false);
       ExternalSort.mergeSortedFiles(files, backward, new LComp(false), Charset.defaultCharset());
       
       System.out.println("Backward sort finished");
       
       long links = readSorted(graph.in, backward, false);
       
       System.out.println("Backward list read");
       
       backward.delete();
       
       int max = Math.max(graph.in.size(), graph.out.size());
       while(graph.in.size() < max)
       	graph.in.add(Collections.EMPTY_LIST);
       while(graph.out.size() < max)
       	graph.out.add(Collections.EMPTY_LIST);

       graph.numLinks = links;
       graph.nullLabels = true;
       
	Global.log().info("Graph loaded and sorted.");

	return graph;
}
 

import com.google.code.externalsorting.ExternalSort; //导入依赖的package包/类
public static DiskUGraph fromFile(File file, File tmpDir, File dbFile)
		throws IOException
	{
	DiskUGraph graph = new DiskUGraph(dbFile, true);

	// * sort the input file by first element
       File forward = new File(tmpDir, "forward.edgelist");
       
       
       List<File> files = ExternalSort.sortInBatch(
       		file, 
       		new LComp(true), ExternalSort.DEFAULTMAXTEMPFILES, 
       		Charset.defaultCharset(), tmpDir, false);
       ExternalSort.mergeSortedFiles(files, forward, new LComp(true), Charset.defaultCharset());
       
       Global.log().info("Forward sort finished");
       
       readSorted(graph.neighbors, forward, true);
       
       Global.log().info("Forward list read");

       forward.delete();
       
       
       File backward = new File(tmpDir, "backward.edgelist");
       
       files = ExternalSort.sortInBatch(
       		file, 
       		new LComp(false), ExternalSort.DEFAULTMAXTEMPFILES, 
       		Charset.defaultCharset(), tmpDir, false);
       ExternalSort.mergeSortedFiles(files, backward, new LComp(false), Charset.defaultCharset());
       
       Global.log().info("Backward sort finished");
       
       long links = readSorted(graph.neighbors, backward, false);
       
       Global.log().info("Backward list read");
       
       backward.delete();
       
       
       graph.numLinks = links;
       graph.nullLabels = true;
       
	Global.log().info("Graph loaded and sorted.");

	
	return graph;
}