Java Vector addAll(int index, Collection c) Method
Java VectoraddAll(int index, Collection c)The method is used to insert all elements in the specified collection intoVectorthe specified position of
The syntax of this method is as follows:
public boolean addAll(int index, Collection<? extends E> c)
Parameter Description
- index: The starting position (index) for inserting elements. The index starts from 0.
- c: The collection to be inserted, whose element types must be compatible with
Vectorthe element types of the Vector.
Return Value
- If
Vectorchanges as a result of calling this method, it returnstrue; otherwise, it returnsfalse。
Method Functionality
addAll(int index, Collection c)The main function of the method is to insert all elements in the collectioncin order into theVectorspecified position ofindex. After insertion, the originalVectorfrom theindexelements starting at that position are shifted backward to make room for the new elements.
Example
The following is a simple example demonstrating how to use theaddAll(int index, Collection c)method:
Example
import java.util.Vector;
import java.util.ArrayList;
public class VectorAddAllExample {
public static void main(String[] args) {
// Create a Vector
Vector<String> vector = new Vector<>();
vector.add("Apple");
vector.add("Banana");
vector.add("Cherry");
// Create an ArrayList
ArrayList<String> list = new ArrayList<>();
list.add("Date");
list.add("Elderberry");
// Insert all elements in the ArrayList into the Vector at index 1
vector.addAll(1, list);
// Output the contents of the Vector
System.out.println("Vector after addAll: " + vector);
}
}
import java.util.ArrayList;
public class VectorAddAllExample {
public static void main(String[] args) {
// Create a Vector
Vector<String> vector = new Vector<>();
vector.add("Apple");
vector.add("Banana");
vector.add("Cherry");
// Create an ArrayList
ArrayList<String> list = new ArrayList<>();
list.add("Date");
list.add("Elderberry");
// Insert all elements in the ArrayList into the Vector at index 1
vector.addAll(1, list);
// Output the contents of the Vector
System.out.println("Vector after addAll: " + vector);
}
}
Output Result
Vector after addAll: [Apple, Date, Elderberry, Banana, Cherry]
Code Explanation
- First, we created a
Vectorand added three elements:"Apple"、"Banana"and"Cherry"。 - Next, we created an
ArrayListand added two elements:"Date"and"Elderberry"。 - Then, we called the
addAll(1, list)method to insert theArrayListall elements in the collection into theVectorindex of the Vector at1. - Finally, we output
Vectorthe contents, and we can see that the new elements were successfully inserted, and the original elements moved backward.
Notes
- Index out of bounds: If the specified
indexexceeds the range of theVector(i.e.index < 0orindex > size()), an exception will be thrownIndexOutOfBoundsExceptionexception. - Empty collection: If the passed-in collection
cis empty (i.e.null), an exception will be thrownNullPointerExceptionexception. - Performance concerns: Since Vector
Vectoris implemented based on arrays, insert operations may lead to array reallocation and element copying, so performance needs to be considered when handling large amounts of data.