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Use double-checked locking and volatile to make RecordHeader thread-safe.
This ensures that synchronization happens only during initialization, and once initialized, subsequent accesses do not acquire any locks.
Note that valueBuffer should also be declared volatile to reduce unnecessary synchronization attempts.
Before
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public class RecordHeader implements Header {
private ByteBuffer keyBuffer;
private String key;
private ByteBuffer valueBuffer;
private byte[] value;
...
public String key() {
if (key == null) {
key = Utils.utf8(keyBuffer, keyBuffer.remaining());
keyBuffer = null;
}
return key;
}
public byte[] value() {
if (value == null && valueBuffer != null) {
value = Utils.toArray(valueBuffer);
valueBuffer = null;
}
return value;
} |
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| Code Block | ||||||
|---|---|---|---|---|---|---|
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public class RecordHeader implements Header {
private ByteBuffer keyBuffer;
private volatile String key;
private volatile ByteBuffer valueBuffer;
private volatile byte[] value;
...
public String key() {
if (key == null) {
synchronized (this) {
if (key == null) {
key = Utils.utf8(keyBuffer, keyBuffer.remaining());
keyBuffer = null;
}
}
}
return key;
}
public byte[] value() {
if (value == nulll && valueBuffer != null) {
synchronized (this) {
if (value == null && valueBuffer != null) {
value = Utils.toArray(valueBuffer);
valueBuffer = null;
}
}
}
return value;
}
} |
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