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Extract IdGenerator into a top-level class

This commit is contained in:
Rossen Stoyanchev 2013-11-25 20:59:51 -05:00
parent a5d87fffd9
commit ce3e55743f
3 changed files with 99 additions and 39 deletions
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62
spring-core/src/main/java/org/springframework/util/AlternativeJdkIdGenerator.java Normal file
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@ -0,0 +1,62 @@
/*
* 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.math.BigInteger;
import java.security.SecureRandom;
import java.util.Random;
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.
*
* @author Rossen Stoyanchev
* @author Rob Winch
* @since 4.0
*/
public class AlternativeJdkIdGenerator implements IdGenerator {
private final Random random;
public AlternativeJdkIdGenerator() {
byte[] seed = new SecureRandom().generateSeed(8);
this.random = new Random(new BigInteger(seed).longValue());
}
public UUID generateId() {
byte[] randomBytes = new byte[16];
this.random.nextBytes(randomBytes);
long mostSigBits = 0;
for (int i = 0; i < 8; i++) {
mostSigBits = (mostSigBits << 8) | (randomBytes[i] & 0xff);
}
long leastSigBits = 0;
for (int i = 8; i < 16; i++) {
leastSigBits = (leastSigBits << 8) | (randomBytes[i] & 0xff);
}
return new UUID(mostSigBits, leastSigBits);
}
}

35
spring-core/src/main/java/org/springframework/util/IdGenerator.java Normal file
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@ -0,0 +1,35 @@
/*
* 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;
/**
* Contract for generating {@link UUID} identifiers.
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public interface IdGenerator {
/**
* Generate a new identifier.
* @return the generated identifier
*/
UUID generateId();
}

41
spring-messaging/src/main/java/org/springframework/messaging/MessageHeaders.java
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@ -20,8 +20,6 @@ import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
@ -30,12 +28,13 @@ import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.UUID;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.AlternativeJdkIdGenerator;
import org.springframework.util.IdGenerator;
/**
* The headers for a {@link Message}
@ -243,40 +242,4 @@ public final class MessageHeaders implements Map<String, Object>, Serializable {
in.defaultReadObject();
}
public static interface IdGenerator {
UUID generateId();
}
/**
* A variation of {@link UUID#randomUUID()} that uses {@link SecureRandom} only for
* the initial seed and {@link Random} thereafter, which provides better performance
* in exchange for less securely random id's.
*/
public static class AlternativeJdkIdGenerator implements IdGenerator {
private final Random random;
public AlternativeJdkIdGenerator() {
byte[] seed = new SecureRandom().generateSeed(8);
this.random = new Random(new BigInteger(seed).longValue());
}
public UUID generateId() {
byte[] randomBytes = new byte[16];
this.random.nextBytes(randomBytes);
long mostSigBits = 0;
for (int i = 0; i < 8; i++) {
mostSigBits = (mostSigBits << 8) | (randomBytes[i] & 0xff);
}
long leastSigBits = 0;
for (int i = 8; i < 16; i++) {
leastSigBits = (leastSigBits << 8) | (randomBytes[i] & 0xff);
}
return new UUID(mostSigBits, leastSigBits);
}
}
}