实现矢量 API 的Java程序
向量是一种线性数据结构，也称为可增长数组。当插入或删除元素时，矢量能够自动调整自身大小。在向量中，数据插入在末尾。它们与 ArrayList 非常相似，但 Vector 是同步的，并且具有一些集合框架不包含的遗留方法。
宣言
public class Vector
其中， E是元素的类型。
Vector API 实现了 Serializable、Cloneable、Iterable
Java
// Java program to implement Vector API
import java.util.*;
public class VectorImplement {
private Vector vector;
// Constructor to create an empty vector(internal array
// has size 10)
public VectorImplement() { vector = new Vector(); }
// Constructor to create a vector with it's element
// as specified in given collection
public VectorImplement(Collection c)
{
vector = new Vector(c);
}
// Constructor to create an empty vector with the given
// initial capacity .
public VectorImplement(int initialCapacity)
{
vector = new Vector(initialCapacity);
}
// Constructor to create an empty vector with the given
// initial capacity and capacity increment.
public VectorImplement(int initialCapacity,
int capacityIncrement)
{
vector = new Vector(initialCapacity,
capacityIncrement);
}
// method to append a specified element to the Vector.
public boolean add(E e) { return vector.add(e); }
// method to insert a given element at the specified
// position in the Vector.
public void add(int index, E element)
{
vector.add(index, element);
}
// method to append all of the elements to the Vector.
public boolean addAll(Collection c)
{
return vector.addAll(c);
}
// method to insert all of the elements of a Collection
// at a specified position.
public boolean addAll(int index,
Collection c)
{
return vector.addAll(index, c);
}
// method to append specific element to the vector.Size
// of vector increases by 1.
public void addElement(E obj)
{
vector.addElement(obj);
}
// method to returns the current capacity of vector.
public int capacity() { return vector.capacity(); }
// method to remove all of the elements of the Vector.
public void clear() { vector.clear(); }
// method to return a clone of this vector.
public Object clone() { return vector.clone(); }
// method to check vector contains a specific element.
public boolean contains(Object o)
{
return vector.contains(o);
}
// method to return true if Vector contains all of the
// elements in the specified Collection.
public boolean containsAll(Collection c)
{
return vector.containsAll(c);
}
// method to Copy the elements of this vector into a
// specific array.
public void copyInto(Object[] anArray)
{
vector.copyInto(anArray);
}
// method to return the element at the specified index.
// **/
public E elementAt(int index)
{
return vector.elementAt(index);
}
// method to return an enumeration of the element of the
// vector. **/
public Enumeration elements()
{
return vector.elements();
}
// method to increase the capacity of this vector to a
// minimum capacity.
public void ensureCapacity(int minCapacity)
{
vector.ensureCapacity(minCapacity);
}
// method to compare a specified elements with this
// Vector for equality.
public boolean equals(Object o)
{
return vector.equals(o);
}
// method to return the first element of the vector
public E firstElement()
{
return vector.firstElement();
}
// method to return the element at the specified index
// in the Vector.
public E get(int index) { return vector.get(index); }
// method to return the hash code value for the Vector
public int hashCode() { return vector.hashCode(); }
// method to return the index of the first occurrence of
// the specified element in
// this vector, or -1 if the vector does not contain the
// specified element.
public int indexOf(Object obj)
{
return vector.indexOf(obj);
}
// method to return the index of the last occurrence of
// a specific element in this
// vector, searching backwards from index, or returns
// -1 if the element is not found.
public int indexOf(Object obj, int index)
{
return vector.indexOf(obj, index);
}
// method to insert a specified object at a specified
// index
public void insertElementAt(E obj, int index)
{
vector.insertElementAt(obj, index);
}
// method to test if the vector has no elements.
public boolean isEmpty() { return vector.isEmpty(); }
// method to return an iterator over the elements in
// this list in proper sequence.
public Iterator iterator()
{
return vector.iterator();
}
// method to return the last element of the vector.
public E lastElement() { return vector.lastElement(); }
// method to return the index of the last occurrence of
// the specific element in the vector, else return -1 if
// the vector does not contain the element.
public int lastIndexOf(Object o)
{
return vector.lastIndexOf(o);
}
// method to return the index of the last occurrence of
// a specific element in the vector, searching backwards
// from index, else returns -1 if the element is not
// found.
public int lastIndexOf(Object o, int index)
{
return vector.lastIndexOf(o, index);
}
// method to return a list iterator over the elements in
// this list.
public ListIterator listIterator()
{
return vector.listIterator();
}
// method to return a list iterator over the elements in
// this list starting at the specific position in the
// list.
public ListIterator listIterator(int index)
{
return vector.listIterator(index);
}
// method to remove the element at the specified
// position in the Vector.
public E remove(int index)
{
return vector.remove(index);
}
// method to remove the first occurrence of a specific
// element in the Vector.
public boolean remove(Object o)
{
return vector.remove(o);
}
// method to remove from this Vector all of its elements
// that are contained in the specified Collection.
public boolean removeAll(Collection c)
{
return vector.removeAll(c);
}
// removes all elements from the vector and set size=0.
public void removeAllElements()
{
vector.removeAllElements();
}
// method to remove the first occurrence of the element
// from the vector. **/
public boolean removeElement(Object obj)
{
return vector.removeElement(obj);
}
// method to retain only the elements in Vector that
// are contained in specified Collection.
public boolean retainAll(Collection c)
{
return vector.removeAll(c);
}
// method to replace the element at the specified
// position in the Vector with another specified element.
public E set(int index, E element)
{
return vector.set(index, element);
}
// method to set the element at the specified index of
// vector
public void setElementAt(E obj, int index)
{
vector.setElementAt(obj, index);
}
// method to set the size of vector
public void setSize(int newSize)
{
vector.setSize(newSize);
}
// method to returns size of vector
public int size() { return vector.size(); }
// method to return a sub-vector between
// fromIndex(inclusive) and toIndex(exclusive).
public List subList(int fromIndex, int toIndex)
{
return vector.subList(fromIndex, toIndex);
}
// method to trim the capacity to the vector current
// size
public void trimToSize() { vector.trimToSize(); }
public static void main(String[] arg)
{
// creating a object of VectorImplement class
VectorImplement vector
= new VectorImplement();
// adding elements to vector
vector.add("one");
vector.add("three");
vector.add("five");
vector.add("ten");
vector.addElement("seven");
vector.addElement("six");
// printing the capacity of vector
System.out.println("The capacity of the vector is "
+ vector.capacity());
// printing the elements of vector
System.out.println("Elements of vector is ");
Enumeration elements = vector.elements();
while (elements.hasMoreElements()) {
System.out.print(elements.nextElement() + "\t");
}
System.out.println();
// checking if vector contains a specific element
System.out.println(
"checking if vector contains element - ten");
if (vector.contains("ten") == true) {
System.out.print(
"The vector contains element ten");
}
else {
System.out.print(
"The vector does not contains element ten");
}
System.out.println();
// printing first element of vector
System.out.println("The first element of vector is "
+ vector.firstElement());
// printing first element of vector
System.out.println("The last element of vector is "
+ vector.lastElement());
// removing an element from the vector
System.out.println("Removing element ten"
+ vector.remove("ten"));
// printing vector size
System.out.println("The size of the vector is "
+ vector.size());
}
} 输出
The capacity of the vector is 10
Elements of vector is
one three five ten seven six
checking if vector contains element - ten
The vector contains element ten
The first element of vector is one
The last element of vector is six
Removing element tentrue
The size of the vector is 5