| /* |
| * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code 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 Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package nsk.share.gc; |
| |
| import java.io.*; |
| import java.util.*; |
| |
| import nsk.share.test.ExecutionController; |
| |
| /** |
| * <tt>NonbranchyTree</tt> defines a tree structure. Each node of the tree |
| * always has one son. A node may have the second son with probability |
| * <tt>branchiness</tt>. |
| */ |
| public class NonbranchyTree { |
| |
| /** Minimal size of each node (in bytes) */ |
| public final static int MIN_NODE_SIZE = 20; |
| private Node root; |
| private Random random; |
| private int numberOfNodes; |
| private float branchiness; |
| private int size; |
| private ExecutionController controller; |
| |
| /** |
| * Creates a new tree with number of nodes not more than |
| * <tt>numberOfNodes</tt>. The implementation uses recursion to build the |
| * tree, so if <tt>StackOverflowError</tt> or <tt>OutOfMemoryError</tt> is |
| * thrown, the recursion is stopped and the method finishes building of the |
| * tree. Each node consists of <tt>byte[]</tt> of length <tt>size</tt>. |
| * |
| * @param numberOfNodes maximum number of nodes for the tree. |
| * @param branchiness probability for each node to have the second son. |
| * @param size number of bytes to store in a node. |
| * |
| * @throws <i>IllegalArgumentException</i> if <tt>numberOfNodes</tt> is |
| * less than 1; or <tt>branchiness</tt> is greater than 1, or less |
| * or equal than 0; or <tt>size</tt> is less than 1. |
| * |
| */ |
| public NonbranchyTree(int numberOfNodes, float branchiness, int size) { |
| this(numberOfNodes, branchiness, size, new Random(System.currentTimeMillis()), null); |
| initTree(); |
| } |
| |
| public NonbranchyTree(int numberOfNodes, float branchiness, int size, ExecutionController controller) { |
| this(numberOfNodes, branchiness, size, new Random(System.currentTimeMillis()), controller); |
| initTree(); |
| } |
| |
| private NonbranchyTree(int numberOfNodes, float branchiness, int size, Random random, ExecutionController controller) { |
| this.numberOfNodes = numberOfNodes; |
| this.branchiness = branchiness; |
| this.size = size; |
| this.random = random; |
| this.controller = controller; |
| } |
| |
| private void initTree() { |
| if (numberOfNodes < 1) { |
| throw new IllegalArgumentException("Illegal number of nodes: " |
| + numberOfNodes + ", must be at " |
| + "least 1."); |
| } |
| if ( (branchiness >= 1) || (branchiness <= 0) ) { |
| throw new IllegalArgumentException("Illegal value of branchiness: " |
| + numberOfNodes + ", must be at " |
| + "greater than 0 and less than " |
| + " 1."); |
| } |
| if (size < 1) { |
| throw new IllegalArgumentException("Illegal size of nodes: " |
| + size + ", must be at least 1."); |
| } |
| root = createTree(numberOfNodes, size); |
| } |
| |
| // Create a new tree with specified number of nodes and size of each node |
| private Node createTree(int numberOfNodes, int size) { |
| // Make sure we respect the controller and stop test after |
| // given time. |
| if (controller != null && !controller.continueExecution()) { |
| return null; |
| } |
| |
| Node node = new Node(size); |
| try { |
| if (numberOfNodes == 0) { |
| // No more nodes need to be built |
| return null; |
| } else if (numberOfNodes == 1) { |
| return node; |
| } else if (numberOfNodes == 2) { |
| node.left = createTree(1, size); |
| return node; |
| } else { |
| // Create a few nodes |
| if (makeRightNode()) { |
| // The node will have two sons |
| int leftNodes = 1 + random.nextInt(numberOfNodes - 2); |
| int rightNodes = numberOfNodes - 1 - leftNodes; |
| |
| node.left = createTree(leftNodes, size); |
| node.right = createTree(rightNodes, size); |
| } else { |
| // The node will have just one son |
| Node leftTree = createTree(numberOfNodes - 1, size); |
| node.left = leftTree; |
| } |
| return node; |
| } // if |
| } catch(StackOverflowError e) { |
| // No more memory for such long tree |
| return node; |
| } catch(OutOfMemoryError e) { |
| // No more memory for such long tree |
| return node; |
| } // try |
| } // createTree() |
| |
| // Define the "branchiness" of the tree |
| private boolean makeRightNode() { |
| return (random.nextFloat() < branchiness); |
| } |
| |
| /** |
| * Bends the tree. A son of a leaf of the tree is set to the root node. |
| * |
| */ |
| public void bend() { |
| bend(root); |
| } |
| |
| // Bend the tree: make a reference from a leat of the tree to the specified |
| // node |
| private void bend(Node markedNode) { |
| Node node = root; |
| |
| while ( (node.left != null) || (node.right != null) ) |
| node = node.left; |
| node.right = markedNode; |
| } |
| |
| /** |
| * Prints the whole tree from the root to the defined PrintStream. |
| * |
| * @param out PrintStream to print the tree in |
| * |
| */ |
| public void print(PrintStream out) { |
| print(out, root); |
| } |
| |
| // Print the sub-tree from the specified node and down |
| private void print(PrintStream out, Node node) { |
| node.print(out); |
| if (node.left != null) |
| print(out, node.left); |
| if (node.right != null) |
| print(out, node.right); |
| } |
| } |
| |
| // The class defines a node of a tree |
| class Node { |
| Node left; |
| Node right; |
| byte[] core; |
| |
| Node(int size) { |
| left = null; |
| right = null; |
| core = new byte[size]; |
| |
| // Initizlize the core array |
| for (int i = 0; i < size; i++) |
| core[i] = (byte) i; |
| } |
| |
| // Print the node info |
| void print(PrintStream out) { |
| out.println("node = " + this + " (" + left + ", " + right + ")"); |
| } |
| } |