qilin.util.queue.ChunkedQueue Maven / Gradle / Ivy
package qilin.util.queue;
/*-
* #%L
* Soot - a J*va Optimization Framework
* %%
* Copyright (C) 2003 Ondrej Lhotak
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
/**
* A queue of Object's. One can add objects to the queue, and they are later read by a QueueReader.
* One can create arbitrary numbers of QueueReader's for a queue, and each one receives all the
* Object's that are added. Only objects that have not been read by all the QueueReader's are kept.
* A QueueReader only receives the Object's added to the queue after the QueueReader was
* created.
*
* @author Ondrej Lhotak
*/
@SuppressWarnings("unchecked")
public class ChunkedQueue {
protected static final Object NULL_CONST = new Object();
protected static final Object DELETED_CONST = new Object();
protected static final int LENGTH = 60;
protected Object[] q;
protected int index;
public ChunkedQueue() {
q = new Object[LENGTH];
index = 0;
}
/** Add an object to the queue. */
public void add(E o) {
if (o == null) {
o = (E) NULL_CONST;
}
if (index == LENGTH - 1) {
Object[] temp = new Object[LENGTH];
q[index] = temp;
q = temp;
index = 0;
}
q[index++] = o;
}
/** Create reader which will read objects from the queue. */
public QueueReader reader() {
return new QueueReader((E[]) q, index);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("[");
boolean isFirst = true;
int idx = index;
Object[] curArray = q;
while (idx < curArray.length) {
Object curObj = curArray[idx];
if (curObj == null) {
break;
}
if (isFirst) {
isFirst = false;
} else {
sb.append(", ");
}
if (curObj instanceof Object[]) {
curArray = (Object[]) curObj;
idx = 0;
} else {
sb.append(curObj.toString());
idx++;
}
}
sb.append("]");
return sb.toString();
}
}