FileCacheTest.java

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 * The Original Code is part of dcm4che, an implementation of DICOM(TM) in
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package org.dcm4che3.filecache;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Iterator;

import org.junit.Before;
import org.junit.Test;

/**
 * @author Gunter Zeilinger <gunterze@gmail.com>
 *
 */
public class FileCacheTest {

    private static final String b_c = Paths.get("b", "c").toString();
    private static final String[] FILES1 = { "a", b_c};
    private static final String[] FILES2 = { "d", "e" };
    private static final String[] FILES3 = { "f", "a" };
    private static final String[] DELETED = { "a", b_c, "b" };
    private static final String[] DELETED_LRU = { b_c, "b", "d", "e" };
    private static final String[] NOT_DELETED = { "d", "e", "f" };
    private static final String[] NOT_DELETED_LRU = FILES3;
    private static final Path CACHE_ROOT_DIR = Paths.get("target", "filecache");
    private static final Path JOURNAL_ROOT_DIR = Paths.get("target", "journaldir");
    private static final String JOURNAL_FILE_NAME_PATTERN = "HHmmss.SSS";
    private static final int FILE_SIZE = 1000;
    private static final long FREED = FILE_SIZE * 2;
    private static final long FREED_LRU = FILE_SIZE * 3;
    private static final long DELAY = 1L;
    private static final long DELAY_LRU = 1000L;

    private FileCache fileCache = new FileCache();

    @Before
    public void setUp() throws Exception {
        fileCache.setFileCacheRootDirectory(CACHE_ROOT_DIR);
        fileCache.setJournalRootDirectory(JOURNAL_ROOT_DIR);
        fileCache.setJournalFileNamePattern(JOURNAL_FILE_NAME_PATTERN);
        fileCache.setJournalMaxEntries(2);
        fileCache.clear();
    }

    @Test
    public void testRegister() throws Exception {
        registerFiles(DELAY);
        assertEquals(Arrays.asList(FILES3), 
                Files.readAllLines(fileCache.getJournalFile(), StandardCharsets.UTF_8));
        try (DirectoryStream<Path> dir =
                Files.newDirectoryStream(fileCache.getJournalDirectory())) {
            Iterator<Path> iter = dir.iterator();
            assertTrue(iter.hasNext());
            Path path1 = iter.next();
            assertTrue(iter.hasNext());
            Path path2 = iter.next();
            assertFalse(iter.hasNext());
            if (path1.compareTo(path2) > 0) {
                Path tmp = path1;
                path1 = path2;
                path2 = tmp;
            }
            assertEquals(Arrays.asList(FILES1),
                    Files.readAllLines(path1, StandardCharsets.UTF_8));
            assertEquals(Arrays.asList(FILES2),
                    Files.readAllLines(path2, StandardCharsets.UTF_8));
        }
    }

    private void registerFiles(long delay) throws Exception {
        for (String file : FILES1)
            fileCache.register(createFile(file));
        Thread.sleep(delay);
        for (String file : FILES2)
            fileCache.register(createFile(file));
        Thread.sleep(delay);
        for (String file : FILES3)
            fileCache.register(createFile(file));
    }

    private Path createFile(String file) throws IOException {
        Path path = toPath(file);
        Files.createDirectories(path.getParent());
        Files.write(path, new byte[FILE_SIZE]);
        return path;
    }

    private Path toPath(String file) {
        return CACHE_ROOT_DIR.resolve(file);
    }

    @Test
    public void testFree() throws Exception {
        registerFiles(DELAY);
        assertEquals(FREED, fileCache.free(FREED));
        assertNotExists(DELETED);
        assertExists(NOT_DELETED);
    }

    @Test
    public void testFreeLRU() throws Exception {
        fileCache.setLeastRecentlyUsed(true);
        registerFiles(DELAY_LRU);
        assertEquals(FREED_LRU, fileCache.free(FREED));
        assertNotExists(DELETED_LRU);
        assertExists(NOT_DELETED_LRU);
    }

    private void assertNotExists(String[] files) {
        for (String file : files)
            assertTrue(Files.notExists(toPath(file)));
    }

    private void assertExists(String[] files) {
        for (String file : files)
            assertTrue(Files.exists(toPath(file)));
    }

}