1 package org.eclipse.aether.util.graph.visitor;
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22 import java.util.AbstractList;
23 import java.util.NoSuchElementException;
24 import java.util.RandomAccess;
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30 class Stack<E>
31 extends AbstractList<E>
32 implements RandomAccess
33 {
34
35 @SuppressWarnings( "unchecked" )
36 private E[] elements = (E[]) new Object[96];
37
38 private int size;
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40 public void push( E element )
41 {
42 if ( size >= elements.length )
43 {
44 @SuppressWarnings( "unchecked" )
45 E[] tmp = (E[]) new Object[size + 64];
46 System.arraycopy( elements, 0, tmp, 0, elements.length );
47 elements = tmp;
48 }
49 elements[size++] = element;
50 }
51
52 public E pop()
53 {
54 if ( size <= 0 )
55 {
56 throw new NoSuchElementException();
57 }
58 return elements[--size];
59 }
60
61 public E peek()
62 {
63 if ( size <= 0 )
64 {
65 return null;
66 }
67 return elements[size - 1];
68 }
69
70 @Override
71 public E get( int index )
72 {
73 if ( index < 0 || index >= size )
74 {
75 throw new IndexOutOfBoundsException( "Index: " + index + ", Size: " + size );
76 }
77 return elements[size - index - 1];
78 }
79
80 @Override
81 public int size()
82 {
83 return size;
84 }
85
86 }