HashAlgorithm_locator entry algorithm-优快云博客

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class HashAlgorithmTest {

	static Random ran = new Random();
	
	/** key's count */
	private static final Integer EXE_TIMES = 100000;
	
	private static final Integer NODE_COUNT = 5;
	
	private static final Integer VIRTUAL_NODE_COUNT = 160;
	
	public static void main(String[] args) {
		HashAlgorithmTest test = new HashAlgorithmTest();
		
		/** Records the times of locating node*/
		Map<Node, Integer> nodeRecord = new HashMap<Node, Integer>();
		
		List<Node> allNodes = test.getNodes(NODE_COUNT);
		KetamaNodeLocator locator = new KetamaNodeLocator(allNodes, HashAlgorithm.KETAMA_HASH, VIRTUAL_NODE_COUNT);
		
		List<String> allKeys = test.getAllStrings();
		for (String key : allKeys) {
			Node node = locator.getPrimary(key);
			
			Integer times = nodeRecord.get(node);
			if (times == null) {
				nodeRecord.put(node, 1);
			} else {
				nodeRecord.put(node, times + 1);
			}
		}
		
		System.out.println("Nodes count : " + NODE_COUNT + ", Keys count : " + EXE_TIMES + ", Normal percent : " + (float) 100 / NODE_COUNT + "%");
		System.out.println("-------------------- boundary  ----------------------");
		for (Map.Entry<Node, Integer> entry : nodeRecord.entrySet()) {
			System.out.println("Node name :" + entry.getKey() + " - Times : " + entry.getValue() + " - Percent : " + (float)entry.getValue() / EXE_TIMES * 100 + "%");
		}
		
	}
	
	
	/**
	 * Gets the mock node by the material parameter
	 * 
	 * @param nodeCount 
	 * 		the count of node wanted
	 * @return
	 * 		the node list
	 */
	private List<Node> getNodes(int nodeCount) {
		List<Node> nodes = new ArrayList<Node>();
		
		for (int k = 1; k <= nodeCount; k++) {
			Node node = new Node("node" + k);
			nodes.add(node);
		}
		
		return nodes;
	}
	
	/**
	 *	All the keys	
	 */
	private List<String> getAllStrings() {
		List<String> allStrings = new ArrayList<String>(EXE_TIMES);
		
		for (int i = 0; i < EXE_TIMES; i++) {
			allStrings.add(generateRandomString(ran.nextInt(50)));
		}
		
		return allStrings;
	}
	
	/**
	 * To generate the random string by the random algorithm
	 * <br>
	 * The char between 32 and 127 is normal char
	 * 
	 * @param length
	 * @return
	 */
	private String generateRandomString(int length) {
		StringBuffer sb = new StringBuffer(length);
		
		for (int i = 0; i < length; i++) {
			sb.append((char) (ran.nextInt(95) + 32));
		}
		
		return sb.toString();
	}
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class HashAlgorithmPercentTest {

	static Random ran = new Random();
	
	/** key's count */
	private static final Integer EXE_TIMES = 100000;
	
	private static final Integer NODE_COUNT = 50;
	
	private static final Integer VIRTUAL_NODE_COUNT = 160;
	
	static List<String> allKeys = null;
	
	static {
		allKeys = getAllStrings();
	}
	
	public static void main(String[] args) {
		
		Map<String, List<Node>> map = generateRecord();
		
		List<Node> allNodes = getNodes(NODE_COUNT);
		System.out.println("Normal case : nodes count : " + allNodes.size());
		call(allNodes, map);
		
		allNodes = getNodes(NODE_COUNT + 8);
		System.out.println("Added case : nodes count : " + allNodes.size());
		call(allNodes, map);
		
		allNodes = getNodes(NODE_COUNT - 10);
		System.out.println("Reduced case : nodes count : " + allNodes.size());
		call(allNodes, map);
		
		int addCount = 0;
		int reduceCount = 0;
		for (Map.Entry<String, List<Node>> entry : map.entrySet()) {
			List<Node> list = entry.getValue();
			
			if (list.size() == 3) {
				if (list.get(0).equals(list.get(1))) {
					addCount++;
				}
				
				if (list.get(0).equals(list.get(2))) {
					reduceCount++;
				}
			} else {
				System.out.println("It's wrong size of list, key is " + entry.getKey() + ", size is " + list.size());
			}
		}
		
		System.out.println(addCount + "   ---   " + reduceCount);
		
		System.out.println("Same percent in added case : " + (float) addCount * 100/ EXE_TIMES + "%");
		System.out.println("Same percent in reduced case : " + (float) reduceCount * 100/ EXE_TIMES + "%");
		
	}
	
	private static void call(List<Node> nodes, Map<String, List<Node>> map) {
		KetamaNodeLocator locator = new KetamaNodeLocator(nodes, HashAlgorithm.KETAMA_HASH, VIRTUAL_NODE_COUNT);
		
		for (Map.Entry<String, List<Node>> entry : map.entrySet()) {
			Node node = locator.getPrimary(entry.getKey());
			
			if (node != null) {
				List<Node> list = entry.getValue();
				list.add(node);
			}
		}
	}
	
	private static Map<String, List<Node>> generateRecord() {
		Map<String, List<Node>> record = new HashMap<String, List<Node>>(EXE_TIMES);
		
		for (String key : allKeys) {
			List<Node> list = record.get(key);
			if (list == null) {
				list = new ArrayList<Node>();
				record.put(key, list);
			}
		}
		
		return record;
	}
	
	
	/**
	 * Gets the mock node by the material parameter
	 * 
	 * @param nodeCount 
	 * 		the count of node wanted
	 * @return
	 * 		the node list
	 */
	private static List<Node> getNodes(int nodeCount) {
		List<Node> nodes = new ArrayList<Node>();
		
		for (int k = 1; k <= nodeCount; k++) {
			Node node = new Node("node" + k);
			nodes.add(node);
		}
		
		return nodes;
	}
	
	/**
	 *	All the keys	
	 */
	private static List<String> getAllStrings() {
		List<String> allStrings = new ArrayList<String>(EXE_TIMES);
		
		for (int i = 0; i < EXE_TIMES; i++) {
			allStrings.add(generateRandomString(ran.nextInt(50)));
		}
		
		return allStrings;
	}
	
	/**
	 * To generate the random string by the random algorithm
	 * <br>
	 * The char between 32 and 127 is normal char
	 * 
	 * @param length
	 * @return
	 */
	private static String generateRandomString(int length) {
		StringBuffer sb = new StringBuffer(length);
		
		for (int i = 0; i < length; i++) {
			sb.append((char) (ran.nextInt(95) + 32));
		}
		
		return sb.toString();
	}
}

import java.util.List;import java.util.SortedMap;import java.util.TreeMap;public final class KetamaNodeLocator {private TreeMap<Long, Node> ketamaNodes;private HashAlgorithm hashAlg;private int numReps = 160; public KetamaNodeLocator(List<Node> nodes, HashAlgorithm alg, int nodeCopies) {hashAlg = alg;ketamaNodes=new TreeMap<Long, Node>(); numReps= nodeCopies; for (Node node : nodes) {for (int i = 0; i < numReps / 4; i++) {byte[] digest = hashAlg.computeMd5(node.getName() + i);for(int h = 0; h < 4; h++) {long m = hashAlg.hash(digest, h);ketamaNodes.put(m, node);}}} }public Node getPrimary(final String k) {byte[] digest = hashAlg.computeMd5(k);Node rv=getNodeForKey(hashAlg.hash(digest, 0));return rv;}Node getNodeForKey(long hash) {final Node rv;Long key = hash;if(!ketamaNodes.containsKey(key)) {SortedMap<Long, Node> tailMap=ketamaNodes.tailMap(key);if(tailMap.isEmpty()) {key=ketamaNodes.firstKey();} else {key=tailMap.firstKey();}//For JDK1.6 version// key = ketamaNodes.ceilingKey(key);// if (key == null) {// key = ketamaNodes.firstKey();// }}rv=ketamaNodes.get(key);return rv;}}

import java.io.UnsupportedEncodingException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public enum HashAlgorithm {/** * MD5-based hash algorithm used by ketama. */KETAMA_HASH;public long hash(byte[] digest, int nTime) {long rv = ((long) (digest[3+nTime*4] & 0xFF) << 24)| ((long) (digest[2+nTime*4] & 0xFF) << 16)| ((long) (digest[1+nTime*4] & 0xFF) << 8)| (digest[0+nTime*4] & 0xFF);return rv & 0xffffffffL; /* Truncate to 32-bits */}/** * Get the md5 of the given key. */public byte[] computeMd5(String k) {MessageDigest md5;try {md5 = MessageDigest.getInstance("MD5");} catch (NoSuchAlgorithmException e) {throw new RuntimeException("MD5 not supported", e);}md5.reset();byte[] keyBytes = null;try {keyBytes = k.getBytes("UTF-8");} catch (UnsupportedEncodingException e) {throw new RuntimeException("Unknown string :" + k, e);}md5.update(keyBytes);return md5.digest();}}