Add JdkIdGenerator and use it in SockJS client

Issue: SPR-12658

Author: rstoyanchev

spring-core/src/main/java/org/springframework/util/AlternativeJdkIdGenerator.java

@@ -22,9 +22,11 @@
 import java.util.UUID;
 
 /**
- * A variation of {@link UUID#randomUUID()} that uses {@link SecureRandom} only for the
- * initial seed and {@link Random} thereafter. This provides better performance in
- * exchange for less securely random id's.
+ * An {@link org.springframework.util.IdGenerator IdGenerator} that uses
+ * {@link SecureRandom} for the initial seed and {@link Random} thereafter
+ * instead of calling {@link UUID#randomUUID()} every time as
+ * {@link org.springframework.util.JdkIdGenerator JdkIdGenerator} does.
+ * This provides a better balance between securely random id's and performance.
  *
  * @author Rossen Stoyanchev
  * @author Rob Winch

spring-core/src/main/java/org/springframework/util/JdkIdGenerator.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2002-2013 the original author or authors.
+ *
+ * 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.
+ */
+
+package org.springframework.util;
+
+import java.util.UUID;
+
+/**
+ * An IdGenerator that calls {@link java.util.UUID#randomUUID()}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.2
+ */
+public class JdkIdGenerator implements IdGenerator {
+
+
+	public UUID generateId() {
+		return UUID.randomUUID();
+	}
+
+}

spring-core/src/main/java/org/springframework/util/SimpleIdGenerator.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2002-2013 the original author or authors.
+ *
+ * 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.
+ */
+
+package org.springframework.util;
+
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * An simple IdGenerator that starts at 1 and increments by 1 with each call.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.2
+ */
+public class SimpleIdGenerator implements IdGenerator {
+
+	private final AtomicLong mostSigBits = new AtomicLong(0);
+
+	private final AtomicLong leastSigBits = new AtomicLong(0);
+
+
+	@Override
+	public UUID generateId() {
+		long leastSigBits = this.leastSigBits.incrementAndGet();
+		if (leastSigBits == 0) {
+			this.mostSigBits.incrementAndGet();
+		}
+		return new UUID(this.mostSigBits.get(), leastSigBits);
+	}
+
+}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/SockJsUrlInfo.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,8 +19,8 @@
 import java.net.URI;
 import java.util.UUID;
 
-import org.springframework.util.AlternativeJdkIdGenerator;
 import org.springframework.util.IdGenerator;
+import org.springframework.util.JdkIdGenerator;
 import org.springframework.web.socket.sockjs.transport.TransportType;
 import org.springframework.web.util.UriComponentsBuilder;
 
@@ -33,7 +33,7 @@
  */
 public class SockJsUrlInfo {
 
-	private static final IdGenerator idGenerator = new AlternativeJdkIdGenerator();
+	private static final IdGenerator idGenerator = new JdkIdGenerator();
 
 
 	private final URI sockJsUrl;