IPSectionKeyGenerator

sharding-jdbc-plugin/src/main/java/com/dangdang/ddframe/rdb/sharding/plugin/keygen/IPSectionKeyGenerator.java

+package com.dangdang.ddframe.rdb.sharding.plugin.keygen;
+
+import com.dangdang.ddframe.rdb.sharding.keygen.DefaultKeyGenerator;
+import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * 浏览 {@link IPKeyGenerator} workerId生成的规则后，感觉对服务器IP后10位（特别是IPV6）数值比较约束。
+ * 有以下优化思路：
+ * 因为workerId最大限制是2^10，我们生成的workerId只要满足小于最大workerId即可。
+ * 1.针对IPV4:
+ * ....IP最大 255.255.255.255。而（255+255+255+255) < 1024。
+ * ....因此采用IP段数值相加即可生成唯一的workerId，不受IP位限制。
+ * 2.针对IPV6:
+ * ....IP最大ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
+ * ....为了保证相加生成出的workerId < 1024,思路是将每个bit位的后6位相加。这样在一定程度上也可以满足workerId不重复的问题。
+ * <p/>
+ * <p/>
+ * 使用这种IP生成workerId的方法,必须保证IP段相加不能重复
+ *
+ * @author DogFc
+ */
+public class IPSectionKeyGenerator implements KeyGenerator {
+
+    private final DefaultKeyGenerator defaultKeyGenerator = new DefaultKeyGenerator();
+
+    static {
+        initWorkerId();
+    }
+
+    static void initWorkerId() {
+        InetAddress address;
+        try {
+            address = InetAddress.getLocalHost();
+        } catch (final UnknownHostException e) {
+            throw new IllegalStateException("Cannot get LocalHost InetAddress, please check your network!");
+        }
+        byte[] ipAddressByteArray = address.getAddress();
+        long workerId = 0L;
+        //IPV4
+        if (ipAddressByteArray.length == 4) {
+            for (byte byteNum : ipAddressByteArray) {
+                workerId += (byteNum & 0xFF);
+            }
+            //IPV6
+        } else if (ipAddressByteArray.length == 16) {
+            for (byte byteNum : ipAddressByteArray) {
+                workerId += (byteNum & 0B111111);
+            }
+        } else {
+            throw new IllegalStateException("Bad LocalHost InetAddress, please check your network!");
+        }
+        DefaultKeyGenerator.setWorkerId(workerId);
+    }
+
+    @Override
+    public Number generateKey() {
+        return defaultKeyGenerator.generateKey();
+    }
+}

sharding-jdbc-plugin/src/test/java/com/dangdang/ddframe/rdb/sharding/plugin/keygen/IPSectionKeyGeneratorTest.java

+/*
+ * Copyright 1999-2015 dangdang.com.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * </p>
+ */
+
+package com.dangdang.ddframe.rdb.sharding.plugin.keygen;
+
+import com.dangdang.ddframe.rdb.sharding.keygen.DefaultKeyGenerator;
+import org.junit.BeforeClass;
+import org.junit.FixMethodOrder;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.junit.runners.MethodSorters;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.lang.reflect.Field;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest(IPSectionKeyGenerator.class)
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+@SuppressWarnings("all")
+public class IPSectionKeyGeneratorTest {
+
+    private static InetAddress ipv4Address;
+
+    private static InetAddress ipv6Address;
+
+
+    @Rule
+    public ExpectedException exception = ExpectedException.none();
+
+    @BeforeClass
+    public static void init() throws UnknownHostException {
+        String ipv4 = "192.168.1.1";
+        byte[] ipv4Byte = new byte[4];
+        String[] ipv4StingArray = ipv4.split("\\.");
+        for (int i = 0; i < 4; i++) {
+            ipv4Byte[i] = (byte) Integer.valueOf(ipv4StingArray[i]).intValue();
+        }
+        ipv4Address = InetAddress.getByAddress("dangdang-db-sharding-dev-233", ipv4Byte);
+
+        String ipv6 = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
+        ipv6Address = InetAddress.getByName(ipv6);
+    }
+
+    @Test
+    public void testIPV4() throws UnknownHostException, NoSuchFieldException, IllegalAccessException {
+        PowerMockito.mockStatic(InetAddress.class);
+        PowerMockito.when(InetAddress.getLocalHost()).thenReturn(ipv4Address);
+        IPSectionKeyGenerator.initWorkerId();
+        Field workerIdField = DefaultKeyGenerator.class.getDeclaredField("workerId");
+        workerIdField.setAccessible(true);
+        assertThat(workerIdField.getLong(DefaultKeyGenerator.class), is(362L));
+    }
+
+    @Test
+    public void testIPV6() throws UnknownHostException, NoSuchFieldException, IllegalAccessException {
+        PowerMockito.mockStatic(InetAddress.class);
+        PowerMockito.when(InetAddress.getLocalHost()).thenReturn(ipv6Address);
+        IPSectionKeyGenerator.initWorkerId();
+        Field workerIdField = DefaultKeyGenerator.class.getDeclaredField("workerId");
+        workerIdField.setAccessible(true);
+        assertThat(workerIdField.getLong(DefaultKeyGenerator.class), is(1008L));
+    }
+
+    @Test
+    public void testUnknownHost() throws UnknownHostException {
+        PowerMockito.mockStatic(InetAddress.class);
+        PowerMockito.when(InetAddress.getLocalHost()).thenThrow(new UnknownHostException());
+        exception.expect(IllegalStateException.class);
+        exception.expectMessage("Cannot get LocalHost InetAddress, please check your network!");
+        IPSectionKeyGenerator.initWorkerId();
+    }
+
+    @Test
+    public void generateId() throws Exception {
+        PowerMockito.mockStatic(InetAddress.class);
+        PowerMockito.when(InetAddress.getLocalHost()).thenReturn(ipv4Address);
+        IPSectionKeyGenerator.initWorkerId();
+        int threadNumber = Runtime.getRuntime().availableProcessors() << 1;
+        ExecutorService executor = Executors.newFixedThreadPool(threadNumber);
+
+        final int taskNumber = threadNumber << 2;
+        final IPSectionKeyGenerator ipSectionKeyGenerator = new IPSectionKeyGenerator();
+        Set<Long> hashSet = new HashSet<>();
+        for (int i = 0; i < taskNumber; i++) {
+            hashSet.add(executor.submit(new Callable<Long>() {
+                @Override
+                public Long call() throws Exception {
+                    return (Long) ipSectionKeyGenerator.generateKey();
+                }
+            }).get());
+        }
+        assertThat(hashSet.size(), is(taskNumber));
+    }
+}