Class java.util.Vector
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Class java.util.Vector
java.lang.Object
|
+----java.util.Vector
- public class Vector
- extends Object
- implements Cloneable
Vector class (a growable array).
Each vector tries to optimize storage management by maintaining
a capacity and a capacityIncrement. The capacity is always at
least as large as the vector size; it is usually larger because
as elements are added to the vector, the vector's
storage increases in chunks the size of capacityIncrement. Setting
the capacity to what you want before inserting a large number of
objects will reduce the amount of incremental reallocation.
You can safely ignore the capacity and the vector will still work
correctly.
-
capacityIncrement
- The size of the increment.
-
elementCount
- The number of elements in the buffer.
-
elementData
- The buffer where elements are stored.
-
Vector(int, int)
- Constructs an empty vector with the specified storage
capacity and the specified capacityIncrement.
-
Vector(int)
- Constructs an empty vector with the specified storage capacity.
-
Vector()
- Constructs an empty vector.
-
addElement(Object)
- Adds the specified object as the last element of the vector.
-
capacity()
- Returns the current capacity of the vector.
-
clone()
- Clones this vector.
-
contains(Object)
- Returns true if the specified object is a value of the
collection.
-
copyInto(Object[])
- Copies the elements of this vector into the specified array.
-
elementAt(int)
- Returns the element at the specified index.
-
elements()
- Returns an enumeration of the elements.
-
ensureCapacity(int)
- Ensures that the vector has at least the specified capacity.
-
firstElement()
- Returns the first element of the sequence.
-
indexOf(Object)
- Searches for the specified object, starting from the first position
and returns an index to it.
-
indexOf(Object, int)
- Searches for the specified object, starting at the specified
position and returns an index to it.
-
insertElementAt(Object, int)
- Inserts the specified object as an element at the specified index.
-
isEmpty()
- Returns true if the collection contains no values.
-
lastElement()
- Returns the last element of the sequence.
-
lastIndexOf(Object)
- Searches backwards for the specified object, starting from the last
position and returns an index to it.
-
lastIndexOf(Object, int)
- Searches backwards for the specified object, starting from the specified
position and returns an index to it.
-
removeAllElements()
- Removes all elements of the vector.
-
removeElement(Object)
- Removes the element from the vector.
-
removeElementAt(int)
- Deletes the element at the specified index.
-
setElementAt(Object, int)
- Sets the element at the specified index to be the specified object.
-
setSize(int)
- Sets the size of the vector.
-
size()
- Returns the number of elements in the vector.
-
toString()
- Converts the vector to a string.
-
trimToSize()
- Trims the vector's capacity down to size.
elementData
protected Object elementData[]
- The buffer where elements are stored.
elementCount
protected int elementCount
- The number of elements in the buffer.
capacityIncrement
protected int capacityIncrement
- The size of the increment. If it is 0 the size of the
the buffer is doubled everytime it needs to grow.
Vector
public Vector(int initialCapacity,
int capacityIncrement)
- Constructs an empty vector with the specified storage
capacity and the specified capacityIncrement.
- Parameters:
- initialCapacity - the initial storage capacity of the vector
- capacityIncrement - how much to increase the element's
size by.
Vector
public Vector(int initialCapacity)
- Constructs an empty vector with the specified storage capacity.
- Parameters:
- initialCapacity - the initial storage capacity of the vector
Vector
public Vector()
- Constructs an empty vector.
copyInto
public final synchronized void copyInto(Object anArray[])
- Copies the elements of this vector into the specified array.
- Parameters:
- anArray - the array where elements get copied into
trimToSize
public final synchronized void trimToSize()
- Trims the vector's capacity down to size. Use this operation to
minimize the storage of a vector. Subsequent insertions will
cause reallocation.
ensureCapacity
public final synchronized void ensureCapacity(int minCapacity)
- Ensures that the vector has at least the specified capacity.
- Parameters:
- minCapacity - the desired minimum capacity
setSize
public final synchronized void setSize(int newSize)
- Sets the size of the vector. If the size shrinks, the extra elements
(at the end of the vector) are lost; if the size increases, the
new elements are set to null.
- Parameters:
- newSize - the new size of the vector
capacity
public final int capacity()
- Returns the current capacity of the vector.
size
public final int size()
- Returns the number of elements in the vector.
Note that this is not the same as the vector's capacity.
isEmpty
public final boolean isEmpty()
- Returns true if the collection contains no values.
elements
public final synchronized Enumeration elements()
- Returns an enumeration of the elements. Use the Enumeration methods on
the returned object to fetch the elements sequentially.
contains
public final boolean contains(Object elem)
- Returns true if the specified object is a value of the
collection.
- Parameters:
- elem - the desired element
indexOf
public final int indexOf(Object elem)
- Searches for the specified object, starting from the first position
and returns an index to it.
- Parameters:
- elem - the desired element
- Returns:
- the index of the element, or -1 if it was not found.
indexOf
public final synchronized int indexOf(Object elem,
int index)
- Searches for the specified object, starting at the specified
position and returns an index to it.
- Parameters:
- elem - the desired element
- index - the index where to start searching
- Returns:
- the index of the element, or -1 if it was not found.
lastIndexOf
public final int lastIndexOf(Object elem)
- Searches backwards for the specified object, starting from the last
position and returns an index to it.
- Parameters:
- elem - the desired element
- Returns:
- the index of the element, or -1 if it was not found.
lastIndexOf
public final synchronized int lastIndexOf(Object elem,
int index)
- Searches backwards for the specified object, starting from the specified
position and returns an index to it.
- Parameters:
- elem - the desired element
- index - the index where to start searching
- Returns:
- the index of the element, or -1 if it was not found.
elementAt
public final synchronized Object elementAt(int index)
- Returns the element at the specified index.
- Parameters:
- index - the index of the desired element
- Throws: ArrayIndexOutOfBoundsException
- If an invalid
index was given.
firstElement
public final synchronized Object firstElement()
- Returns the first element of the sequence.
- Throws: NoSuchElementException
- If the sequence is empty.
lastElement
public final synchronized Object lastElement()
- Returns the last element of the sequence.
- Throws: NoSuchElementException
- If the sequence is empty.
setElementAt
public final synchronized void setElementAt(Object obj,
int index)
- Sets the element at the specified index to be the specified object.
The previous element at that position is discarded.
- Parameters:
- obj - what the element is to be set to
- index - the specified index
- Throws: ArrayIndexOutOfBoundsException
- If the index was
invalid.
removeElementAt
public final synchronized void removeElementAt(int index)
- Deletes the element at the specified index. Elements with an index
greater than the current index are moved down.
- Parameters:
- index - the element to remove
- Throws: ArrayIndexOutOfBoundsException
- If the index was invalid.
insertElementAt
public final synchronized void insertElementAt(Object obj,
int index)
- Inserts the specified object as an element at the specified index.
Elements with an index greater or equal to the current index
are shifted up.
- Parameters:
- obj - the element to insert
- index - where to insert the new element
- Throws: ArrayIndexOutOfBoundsException
- If the index was invalid.
addElement
public final synchronized void addElement(Object obj)
- Adds the specified object as the last element of the vector.
- Parameters:
- obj - the element to be added
removeElement
public final synchronized boolean removeElement(Object obj)
- Removes the element from the vector. If the object occurs more
than once, only the first is removed. If the object is not an
element, returns false.
- Parameters:
- obj - the element to be removed
- Returns:
- true if the element was actually removed; false otherwise.
removeAllElements
public final synchronized void removeAllElements()
- Removes all elements of the vector. The vector becomes empty.
clone
public synchronized Object clone()
- Clones this vector. The elements are not cloned.
- Overrides:
- clone in class Object
toString
public final synchronized String toString()
- Converts the vector to a string. Useful for debugging.
- Overrides:
- toString in class Object
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