Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 195 insertions, 0 deletions

diff --git a/guava/src/com/google/common/collect/ObjectArrays.java b/guava/src/com/google/common/collect/ObjectArrays.java
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+/*
+ * Copyright (C) 2007 The Guava Authors
+ *
+ * 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 com.google.common.collect;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.annotations.GwtIncompatible;
+
+import java.lang.reflect.Array;
+import java.util.Collection;
+
+import javax.annotation.Nullable;
+
+/**
+ * Static utility methods pertaining to object arrays.
+ *
+ * @author Kevin Bourrillion
+ * @since 2.0 (imported from Google Collections Library)
+ */
+@GwtCompatible(emulated = true)
+public final class ObjectArrays {
+  static final Object[] EMPTY_ARRAY = new Object[0];
+
+  private ObjectArrays() {}
+
+  /**
+   * Returns a new array of the given length with the specified component type.
+   *
+   * @param type the component type
+   * @param length the length of the new array
+   */
+  @GwtIncompatible("Array.newInstance(Class, int)")
+  @SuppressWarnings("unchecked")
+  public static <T> T[] newArray(Class<T> type, int length) {
+    return (T[]) Array.newInstance(type, length);
+  }
+
+  /**
+   * Returns a new array of the given length with the same type as a reference
+   * array.
+   *
+   * @param reference any array of the desired type
+   * @param length the length of the new array
+   */
+  public static <T> T[] newArray(T[] reference, int length) {
+    return Platform.newArray(reference, length);
+  }
+
+  /**
+   * Returns a new array that contains the concatenated contents of two arrays.
+   *
+   * @param first the first array of elements to concatenate
+   * @param second the second array of elements to concatenate
+   * @param type the component type of the returned array
+   */
+  @GwtIncompatible("Array.newInstance(Class, int)")
+  public static <T> T[] concat(T[] first, T[] second, Class<T> type) {
+    T[] result = newArray(type, first.length + second.length);
+    System.arraycopy(first, 0, result, 0, first.length);
+    System.arraycopy(second, 0, result, first.length, second.length);
+    return result;
+  }
+
+  /**
+   * Returns a new array that prepends {@code element} to {@code array}.
+   *
+   * @param element the element to prepend to the front of {@code array}
+   * @param array the array of elements to append
+   * @return an array whose size is one larger than {@code array}, with
+   *     {@code element} occupying the first position, and the
+   *     elements of {@code array} occupying the remaining elements.
+   */
+  public static <T> T[] concat(@Nullable T element, T[] array) {
+    T[] result = newArray(array, array.length + 1);
+    result[0] = element;
+    System.arraycopy(array, 0, result, 1, array.length);
+    return result;
+  }
+
+  /**
+   * Returns a new array that appends {@code element} to {@code array}.
+   *
+   * @param array the array of elements to prepend
+   * @param element the element to append to the end
+   * @return an array whose size is one larger than {@code array}, with
+   *     the same contents as {@code array}, plus {@code element} occupying the
+   *     last position.
+   */
+  public static <T> T[] concat(T[] array, @Nullable T element) {
+    T[] result = arraysCopyOf(array, array.length + 1);
+    result[array.length] = element;
+    return result;
+  }
+
+  /** GWT safe version of Arrays.copyOf. */
+  static <T> T[] arraysCopyOf(T[] original, int newLength) {
+    T[] copy = newArray(original, newLength);
+    System.arraycopy(
+        original, 0, copy, 0, Math.min(original.length, newLength));
+    return copy;
+  }
+
+  /**
+   * Returns an array containing all of the elements in the specified
+   * collection; the runtime type of the returned array is that of the specified
+   * array. If the collection fits in the specified array, it is returned
+   * therein. Otherwise, a new array is allocated with the runtime type of the
+   * specified array and the size of the specified collection.
+   *
+   * <p>If the collection fits in the specified array with room to spare (i.e.,
+   * the array has more elements than the collection), the element in the array
+   * immediately following the end of the collection is set to {@code null}.
+   * This is useful in determining the length of the collection <i>only</i> if
+   * the caller knows that the collection does not contain any null elements.
+   *
+   * <p>This method returns the elements in the order they are returned by the
+   * collection's iterator.
+   *
+   * <p>TODO(kevinb): support concurrently modified collections?
+   *
+   * @param c the collection for which to return an array of elements
+   * @param array the array in which to place the collection elements
+   * @throws ArrayStoreException if the runtime type of the specified array is
+   *     not a supertype of the runtime type of every element in the specified
+   *     collection
+   */
+  static <T> T[] toArrayImpl(Collection<?> c, T[] array) {
+    int size = c.size();
+    if (array.length < size) {
+      array = newArray(array, size);
+    }
+    fillArray(c, array);
+    if (array.length > size) {
+      array[size] = null;
+    }
+    return array;
+  }
+
+  /**
+   * Returns an array containing all of the elements in the specified
+   * collection. This method returns the elements in the order they are returned
+   * by the collection's iterator. The returned array is "safe" in that no
+   * references to it are maintained by the collection. The caller is thus free
+   * to modify the returned array.
+   *
+   * <p>This method assumes that the collection size doesn't change while the
+   * method is running.
+   *
+   * <p>TODO(kevinb): support concurrently modified collections?
+   *
+   * @param c the collection for which to return an array of elements
+   */
+  static Object[] toArrayImpl(Collection<?> c) {
+    return fillArray(c, new Object[c.size()]);
+  }
+
+  private static Object[] fillArray(Iterable<?> elements, Object[] array) {
+    int i = 0;
+    for (Object element : elements) {
+      array[i++] = element;
+    }
+    return array;
+  }
+
+  /**
+   * Swaps {@code array[i]} with {@code array[j]}.
+   */
+  static void swap(Object[] array, int i, int j) {
+    Object temp = array[i];
+    array[i] = array[j];
+    array[j] = temp;
+  }
+
+  // We do this instead of Preconditions.checkNotNull to save boxing and array
+  // creation cost.
+  static Object checkElementNotNull(Object element, int index) {
+    if (element == null) {
+      throw new NullPointerException("at index " + index);
+    }
+    return element;
+  }
+}