File	Doc	Category	Size	Date	Package
CharQueue.java	API Doc	Glassfish v2 API	2716	Wed Aug 30 15:34:04 BST 2006	persistence.antlr

CharQueue

• java.lang.Object

Fields Summary
protected char[]	buffer Physical circular buffer of tokens
private int	sizeLessOne buffer.length-1 for quick modulos
private int	offset physical index of front token
protected int	nbrEntries number of tokens in the queue

Constructors Summary
public CharQueue(int minSize) // Find first power of 2 >= to requested size int size; if ( minSize<0 ) { init(16); // pick some value for them return; } // check for overflow if ( minSize>=(Integer.MAX_VALUE/2) ) { init(Integer.MAX_VALUE); // wow that's big. return; } for (size = 2; size < minSize; size *= 2) { } init(size);

Methods Summary
public final void	append(char tok) Add token to end of the queue param tok The token to add if (nbrEntries == buffer.length) { expand(); } buffer[(offset + nbrEntries) & sizeLessOne] = tok; nbrEntries++;
public final char	elementAt(int idx) Fetch a token from the queue by index param idx The index of the token to fetch, where zero is the token at the front of the queue return buffer[(offset + idx) & sizeLessOne];
private final void	expand() Expand the token buffer by doubling its capacity char[] newBuffer = new char[buffer.length * 2]; // Copy the contents to the new buffer // Note that this will store the first logical item in the // first physical array element. for (int i = 0; i < buffer.length; i++) { newBuffer[i] = elementAt(i); } // Re-initialize with new contents, keep old nbrEntries buffer = newBuffer; sizeLessOne = buffer.length - 1; offset = 0;
public void	init(int size) Initialize the queue. param size The initial size of the queue // Allocate buffer buffer = new char[size]; // Other initialization sizeLessOne = size - 1; offset = 0; nbrEntries = 0;
public final void	removeFirst() Remove char from front of queue offset = (offset + 1) & sizeLessOne; nbrEntries--;
public final void	reset() Clear the queue. Leaving the previous buffer alone. offset = 0; nbrEntries = 0;