Java Collections.nCopies方法代码示例

import java.util.Collections; //导入方法依赖的package包/类
@Override
protected void setUp() throws Exception {
    super.setUp();
    clearWorkDir();
    
    jar = new File(getWorkDir(), "x.jar");
    JarOutputStream os = new JarOutputStream(
        new FileOutputStream(jar)
    );
    os.putNextEntry(new ZipEntry("fldr/plain.txt"));
    os.write("Ahoj\n".getBytes());
    os.closeEntry();
    os.close();
    JarClassLoader registerJarSource = new JarClassLoader(
        Collections.nCopies(1, jar),
        new ClassLoader[] { getClass().getClassLoader() }
    );
    assertNotNull("Registered", registerJarSource);
}
 

import java.util.Collections; //导入方法依赖的package包/类
public void testMetaInfServicesPackageNotListedByDefault() throws Exception {
    File jar = new File(getWorkDir(), "non-empty.jar");
    TestFileUtils.writeZipFile(jar, 
        "META-INF/services/java.lang.Runnable:1"
    );
    JarClassLoader l1 = new JarClassLoader(Collections.nCopies(1, jar), new ClassLoader[] {
        ClassLoader.getSystemClassLoader()
    });
    
    Set<ProxyClassLoader> set = ProxyClassPackages.findCoveredPkg("META-INF.services");
    assertNull("No JAR covers META-INF.services: " + set, set);

    ProxyClassLoader l2 = new ProxyClassLoader(new ProxyClassLoader[] { l1 }, true);

    Enumeration<URL> en = l2.getResources("META-INF/services/java.lang.Runnable");
    assertTrue("Some are there", en.hasMoreElements());
    URL one = en.nextElement();
    assertFalse("And that is all", en.hasMoreElements());
    
    URL alternative = l2.getResource("META-INF/services/java.lang.Runnable");
    assertEquals("Same URL", one, alternative);
    
    ProxyClassPackages.removeCoveredPakcages(l1);
}
 

import java.util.Collections; //导入方法依赖的package包/类
public void testLazyVisDestroy() throws Exception {
    LazyChildren lch = new LazyChildren();
    AbstractNode a = new AbstractNode(lch);
    List<String> arr = Collections.nCopies(100, "A");
    lch.keys(arr.toArray(new String[0]));

    TreeNode ta = Visualizer.findVisualizer(a);
    final TreeNode snd = ta.getChildAt(2);

    Reference<Node> sndNode = new WeakReference<Node>(Visualizer.findNode(snd));

    assertEquals("Child check", "A", snd.toString());
    assertEquals("Counter should be 1", 1, lch.cnt);

    a.destroy();

    assertGC("Whole subtree under a can be GCed now", sndNode);
}
 

import java.util.Collections; //导入方法依赖的package包/类
@Override
@NonNull
public List<DataObject> sort(@NonNull final List<DataObject> original) {
    if (!isLibrary()) {
        return original;
    }
    final List<DataObject> result = new ArrayList<>(Collections.<DataObject>nCopies(CAT_MAP.size(), null));
    for (DataObject dobj : original) {
        final String name = dobj.getName();
        final Integer index = CAT_MAP.get(name);
        if (index == null) {
            result.add(dobj);
        } else {
            result.set (index, dobj);
        }
    }
    return filterNulls(result);
}
 

import java.util.Collections; //导入方法依赖的package包/类
@Test
public void toStringWithSmallCollections() {
    List<String> strings = Collections.nCopies(1, "0");
    List<Integer> ints =  Collections.nCopies(1, 1);
    List<Long> longs =  Collections.nCopies(1, 2L);
    List<Double> doubles =  Collections.nCopies(1, 3.1D);
    List<Float> floats =  Collections.nCopies(1, 4.2F);
    List<Byte> bytes =  Collections.nCopies(1, (byte)5);
    List<Character> chars =  Collections.nCopies(1, '6');
    
    assertThat(LogHelper.toString(strings), is("[0]"));
    assertThat(LogHelper.toString(ints), is("[1]"));
    assertThat(LogHelper.toString(longs), is("[2]"));
    assertThat(LogHelper.toString(doubles), is("[3.1]"));
    assertThat(LogHelper.toString(floats), is("[4.2]"));
    assertThat(LogHelper.toString(bytes), is("[5]"));
    assertThat(LogHelper.toString(chars), is("[6]"));
}
 

import java.util.Collections; //导入方法依赖的package包/类
public static void main(String[] args) {

    /*
      To create a List containing n copies of specified Object use,
      static List nCopies(int n, Object obj) method of Java Collections class.

      This method returns immutable List containing n copies of the
      specified Object.
    */

    List list = Collections.nCopies(5, "A");

    //iterate through newly created list
    System.out.println("List contains, ");
    Iterator itr = list.iterator();

    while (itr.hasNext()) System.out.println(itr.next());
  }
 

import java.util.Collections; //导入方法依赖的package包/类
@Test
public void testLarge() throws Exception {
  Message m = new Message();
  // list size 80 MB
  m.l = new ArrayList<Integer>(Collections.nCopies(20 * 1024 * 1024, 1000000007));
  Message m2 = marshaller.parse(marshaller.stream(m));
  assertNotSame(m, m2);
  assertEquals(m.l.size(), m2.l.size());
}
 

import java.util.Collections; //导入方法依赖的package包/类
/**
 * Initializing from too large collection throws IllegalArgumentException
 */
public void testConstructor_collectionTooLarge() {
    // just barely fits - succeeds
    new ArrayBlockingQueue(SIZE, false,
                           Collections.nCopies(SIZE, ""));
    try {
        new ArrayBlockingQueue(SIZE - 1, false,
                               Collections.nCopies(SIZE, ""));
        shouldThrow();
    } catch (IllegalArgumentException success) {}
}
 

import java.util.Collections; //导入方法依赖的package包/类
/**
 * Attempt to parse the given object as a set of parameters for this handler.
 *
 * @param params the parameter block to parse
 * @return true if the object made sense for this handler; false otherwise.
 */
@Override
public boolean parseParameters(Object params)
{
    if (params == null || !(params instanceof BuildBattleDecorator))
        return false;

    this.params = (BuildBattleDecorator) params;

    this.sourceBounds = this.params.getGoalStructureBounds();
    this.destBounds = this.params.getPlayerStructureBounds();
    this.delta = new Vec3i(destBounds.getMin().getX() - sourceBounds.getMin().getX(),
                           destBounds.getMin().getY() - sourceBounds.getMin().getY(),
                           destBounds.getMin().getZ() - sourceBounds.getMin().getZ());
    
    this.structureVolume = volumeOfBounds(this.sourceBounds);
    assert(this.structureVolume == volumeOfBounds(this.destBounds));
    this.dest = new ArrayList<IBlockState>(Collections.nCopies(this.structureVolume, (IBlockState)null));
    this.source = new ArrayList<IBlockState>(Collections.nCopies(this.structureVolume, (IBlockState)null));
    
    DrawBlockBasedObjectType tickBlock = this.params.getBlockTypeOnCorrectPlacement();
    DrawBlockBasedObjectType crossBlock = this.params.getBlockTypeOnIncorrectPlacement();

    this.blockTypeOnCorrectPlacement = (tickBlock != null) ? new XMLBlockState(tickBlock.getType(), tickBlock.getColour(), tickBlock.getFace(), tickBlock.getVariant()) : null;
    this.blockTypeOnIncorrectPlacement = (crossBlock != null) ? new XMLBlockState(crossBlock.getType(), crossBlock.getColour(), crossBlock.getFace(), crossBlock.getVariant()) : null;
    return true;
}
 

import java.util.Collections; //导入方法依赖的package包/类
static MethodHandle MH_hashArguments(Class<? extends Object[]> arrayClass, int arity) {
    if (arrayClass == Object[].class)
        return MH_hashArguments(arity);
    ArrayList<Class<?>> ptypes = new ArrayList<>(Collections.<Class<?>>nCopies(arity, arrayClass.getComponentType()));
    MethodType mt = MethodType.methodType(Object.class, ptypes);
    return MH_hashArguments_VA.asType(mt);
}
 

import java.util.Collections; //导入方法依赖的package包/类
@Test
public void reallyLongCashFlow() {
    int size = 1000000;
    TimeSeries sampleTimeSeries = new MockTimeSeries(Collections.nCopies(size, (Tick) new MockTick(10)));
    TradingRecord tradingRecord = new BaseTradingRecord(Order.buyAt(0), Order.sellAt(size - 1));
    CashFlow cashFlow = new CashFlow(sampleTimeSeries, tradingRecord);
    assertDecimalEquals(cashFlow.getValue(size - 1), 1);
}
 

import java.util.Collections; //导入方法依赖的package包/类
@SuppressWarnings("Convert2Lambda")
private void concurrentVerify(final JWT jwt, final String token) throws TimeoutException, InterruptedException {
    final Waiter waiter = new Waiter();
    List<VerifyTask> tasks = Collections.nCopies(REPEAT_COUNT, new VerifyTask(waiter, jwt, token));
    executor.invokeAll(tasks, TIMEOUT, TimeUnit.MILLISECONDS);
    waiter.await(TIMEOUT, REPEAT_COUNT);
}
 

import java.util.Collections; //导入方法依赖的package包/类
/**
 * Searches the tokens in the words given taking into account their relative positioning.
 *
 * @param words words to search from
 */
private void search(List<String> words) {
    int minDistance = Integer.MAX_VALUE, startTokenIndex = 0;

    while (startTokenIndex < words.size()) {
        List<Integer> tokenIndexes = new ArrayList<>(Collections.nCopies(tokens.size(), -1));
        int subListTokenIndex = words.subList(startTokenIndex, words.size()).indexOf(tokens.get(0));
        int newTokenIndex = subListTokenIndex + startTokenIndex;
        tokenIndexes.set(0, newTokenIndex);
        if (subListTokenIndex == -1) {
            break;
        }
        for (int i = 1; i < tokens.size(); ++i) {
            subListTokenIndex = words.subList(newTokenIndex + 1, words.size()).indexOf(tokens.get(i));
            if (subListTokenIndex == -1) {
                break;
            }
            newTokenIndex = subListTokenIndex + newTokenIndex + 1;
            tokenIndexes.set(i, newTokenIndex);
        }
        if (subListTokenIndex == -1) {
            break;
        }
        int minDistanceCandidate = tokenIndexes.get(tokenIndexes.size() - 1) - tokenIndexes.get(0);
        if (minDistanceCandidate < minDistance) {
            minDistance = minDistanceCandidate;
            result.tokenIndexes = tokenIndexes;
        }
        startTokenIndex = tokenIndexes.get(0) + 1;
    }
}
 

import java.util.Collections; //导入方法依赖的package包/类
public Statistics() {
    mMonthlyData = new ArrayList<>(Collections.nCopies(12, 0));
    mCategoryData = new SparseIntArray();
}
 

import java.util.Collections; //导入方法依赖的package包/类
public CircularArrayList(int capacity) {
	n = capacity + 1;
	buf = new ArrayList<E>(Collections.nCopies(n, (E) null));
}