Java等效的"splice(a，b，...)"方法在JavaScript方法中 [英] Java eqivalent method of "splice(a,b,...)" in JavaScript method

问题描述

someArray.splice(a，b，...)方法在数组中添加项或从数组中删除项.用Java语言实现这种方法的最佳和简单解决方案是什么?假设我们有 String [] 数组.

someArray.splice(a,b,...) method in JavaScript adds or removes items to/from array. What could be good and simple solution to implement such method in Java language? Assume we have String[] array.

推荐答案

根据

以下JUnit代码测试了此实现:

The following JUnit code tests this implementation:

@Test
  public void testSplice() {
    final String[] array = new String[] {"a", "b", "c", "d", "e", "f"};

    Assert.assertArrayEquals(new String[] {"c", "d", "e", "f"}, Arrays.splice(array, 0, 2));
    Assert.assertArrayEquals(new String[] {"a", "d", "e", "f"}, Arrays.splice(array, 1, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "e", "f"}, Arrays.splice(array, 2, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "f"}, Arrays.splice(array, 3, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, 4, 2));
    try {
      Arrays.splice(array, 5, 2);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }

    try {
      Arrays.splice(array, -2, 3);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, -2, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "f"}, Arrays.splice(array, -3, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "e", "f"}, Arrays.splice(array, -4, 2));
    Assert.assertArrayEquals(new String[] {"a", "d", "e", "f"}, Arrays.splice(array, -5, 2));
    Assert.assertArrayEquals(new String[] {"c", "d", "e", "f"}, Arrays.splice(array, -6, 2));
    try {
      Arrays.splice(array, -7, 2);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }

    Assert.assertArrayEquals(new String[] {}, Arrays.splice(array, 0));
    Assert.assertArrayEquals(new String[] {"a"}, Arrays.splice(array, 1));
    Assert.assertArrayEquals(new String[] {"a", "b"}, Arrays.splice(array, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c"}, Arrays.splice(array, 3));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, 4));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e"}, Arrays.splice(array, 5));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e", "f"}, Arrays.splice(array, 6));
    try {
      Arrays.splice(array, 7);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }

    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e"}, Arrays.splice(array, -1));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, -2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c"}, Arrays.splice(array, -3));
    Assert.assertArrayEquals(new String[] {"a", "b"}, Arrays.splice(array, -4));
    Assert.assertArrayEquals(new String[] {"a"}, Arrays.splice(array, -5));
    Assert.assertArrayEquals(new String[] {}, Arrays.splice(array, -6));
    try {
      Arrays.splice(array, -7);
      Assert.fail("Expected NegativeArraySizeException");
    }
    catch (final NegativeArraySizeException e) {
    }

    Assert.assertArrayEquals(new String[] {"x", "y", "z", "c", "d", "e", "f"}, Arrays.splice(array, 0, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "x", "y", "z", "d", "e", "f"}, Arrays.splice(array, 1, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "x", "y", "z", "e", "f"}, Arrays.splice(array, 2, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "x", "y", "z", "f"}, Arrays.splice(array, 3, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "x", "y", "z"}, Arrays.splice(array, 4, 2, "x", "y", "z"));
    try {
      Arrays.splice(array, 5, 2, "x", "y", "z");
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }

    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "x", "y", "z"}, Arrays.splice(array, -2, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "x", "y", "z", "f"}, Arrays.splice(array, -3, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "x", "y", "z", "e", "f"}, Arrays.splice(array, -4, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "x", "y", "z", "d", "e", "f"}, Arrays.splice(array, -5, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"x", "y", "z", "c", "d", "e", "f"}, Arrays.splice(array, -6, 2, "x", "y", "z"));
    try {
      Arrays.splice(array, -7, 2, "x", "y", "z");
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
  }

编辑:正如@denys-séguret正确指出的那样，此实现与JavaScript规范不同，因为它不会更改/修改原始数组.相反，此实现返回一个新的数组实例.

As @denys-séguret pointed out correctly, this implementation differs from the JavaScript spec as it does not mutate/modify the original array. Instead, this implementation returns a new array instance.

在给定的maven存储库中，以下maven工件可以使用此实现:

This implementation is available with the following maven artifact, at the given maven repo:

<project>
  ...
  <dependencies>
    <dependency>
      <groupId>org.safris.commons</groupId>
      <artifactId>commons-lang</artifactId>
      <version>1.6.4</version>
    </dependency>
  </dependencies>
  ...
  <repositories>
    <repository>
      <id>mvn.repo.safris.org</id>
      <url>http://mvn.repo.safris.org/m2</url>
    </repository>
  </repositories>
  ...
</project>

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