ConcurrentBlockingQueue，自己写了一份增加理解，很久之前写代码，很地方不工整不要在意。
Java代码复习
date：2017-02-01 author：zhangjianxin
1. ConcurrentBlockingQueue
package me.firsh.tools;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
public class ConcurrentBlockingQueue<T extends Exchengeable> {
public long p1, p2, p3, p4, p5, p6, p7; // cache line padding
private volatile long proCursor = 0;
public long p8, p9, p10, p11, p12, p13, p14; // cache line padding
private volatile long comsumeCursor = 0;
private final AtomicLong produceSequence = new AtomicLong(0);
private final AtomicLong comsumeSequence = new AtomicLong(0);
private final Exchengeable[] entries;
private final int ringModMask;
private final int nextHighestPowerOfTwo(int v) {
v--;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
v++;
return v;
}
public ConcurrentBlockingQueue(final int size) {
int sizeAsPowerOfTwo = Math.max(nextHighestPowerOfTwo(size), 1);
ringModMask = sizeAsPowerOfTwo - 1;
entries = new Exchengeable[sizeAsPowerOfTwo];
}
@SuppressWarnings("unchecked")
private T getEntry(final long sequence) {
return (T) entries[(int) (sequence & ringModMask)];
}
private void setEntry(final long sequence, T t) {
final int index = (int) (sequence & ringModMask);
if (entries[index] == null) {
entries[index] = t;
} else {
entries[index].exchange(t);
}
}
private final long waitForNextProduce() {
while (true) {
if (produceSequence.get() - comsumeCursor < entries.length) {
return produceSequence.incrementAndGet();
} else {
try {
Thread.yield();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public void put(T t) {
long sequence = waitForNextProduce();
setEntry(sequence - 1, t);
proCursor = sequence;
}
private final long waitForComsume() {
while (true) {
long comsume = proCursor - comsumeSequence.get();
if (comsume > 0 && comsume <= entries.length) {
return comsumeSequence.incrementAndGet();
} else {
try {
Thread.yield();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public T take() {
long nextSequence = waitForComsume();
comsumeCursor = nextSequence;
return getEntry(nextSequence - 1);
}
public boolean put(T t, long time, TimeUnit unit) throws IOException {
put(t);
return true;
}
public T take(long time, TimeUnit unit) throws IOException {
return take();
}
}
2.LengthByteArrayEncoder
@Sharable
public class LengthByteArrayEncoder extends MessageToMessageEncoder<byte[]> {
@Override
protected void encode(ChannelHandlerContext ctx, byte[] msg,
List<Object> out) throws Exception {
byte[] b1 = toBytes(msg.length);
// out.add(Unpooled.wrappedBuffer(b1)); // length
// out.add(Unpooled.wrappedBuffer(msg)); // data
ByteBuf buf = Unpooled.wrappedBuffer(b1, msg); // length , data
out.add(buf);
}
static final byte[] N1 = { B2Type.INT_N1 };
static final byte[] I0 = { B2Type.INT_0 };
static final byte[] I1 = { B2Type.INT_1 };
static final byte[] I2 = { B2Type.INT_2 };
static final byte[] I3 = { B2Type.INT_3 };
static final byte[] I4 = { B2Type.INT_4 };
static final byte[] I5 = { B2Type.INT_5 };
static final byte[] I6 = { B2Type.INT_6 };
static final byte[] I7 = { B2Type.INT_7 };
static final byte[] I8 = { B2Type.INT_8 };
static final byte[] I9 = { B2Type.INT_9 };
static final byte[] I10 = { B2Type.INT_10 };
static final byte[] I11 = { B2Type.INT_11 };
static final byte[] I12 = { B2Type.INT_12 };
static final byte[] I13 = { B2Type.INT_13 };
static final byte[] I14 = { B2Type.INT_14 };
static final byte[] I15 = { B2Type.INT_15 };
static final byte[] I16 = { B2Type.INT_16 };
static final byte[] I17 = { B2Type.INT_17 };
static final byte[] I18 = { B2Type.INT_18 };
static final byte[] I19 = { B2Type.INT_19 };
static final byte[] I20 = { B2Type.INT_20 };
static final byte[] I21 = { B2Type.INT_21 };
static final byte[] I22 = { B2Type.INT_22 };
static final byte[] I23 = { B2Type.INT_23 };
static final byte[] I24 = { B2Type.INT_24 };
static final byte[] I25 = { B2Type.INT_25 };
static final byte[] I26 = { B2Type.INT_26 };
static final byte[] I27 = { B2Type.INT_27 };
static final byte[] I28 = { B2Type.INT_28 };
static final byte[] I29 = { B2Type.INT_29 };
static final byte[] I30 = { B2Type.INT_30 };
static final byte[] I31 = { B2Type.INT_31 };
static final byte[] I32 = { B2Type.INT_32 };
static final byte[] toBytes(int v) {
switch (v) {
case -1:
return N1;
case 0:
return I0;
case 1:
return I1;
case 2:
return I2;
case 3:
return I3;
case 4:
return I4;
case 5:
return I5;
case 6:
return I6;
case 7:
return I7;
case 8:
return I8;
case 9:
return I9;
case 10:
return I10;
case 11:
return I11;
case 12:
return I12;
case 13:
return I13;
case 14:
return I14;
case 15:
return I15;
case 16:
return I16;
case 17:
return I17;
case 18:
return I18;
case 19:
return I19;
case 20:
return I20;
case 21:
return I21;
case 22:
return I22;
case 23:
return I23;
case 24:
return I24;
case 25:
return I25;
case 26:
return I26;
case 27:
return I27;
case 28:
return I28;
case 29:
return I29;
case 30:
return I30;
case 31:
return I31;
case 32:
return I32;
default:
if (v >= NumEx.BYTE_MIN_VALUE && v <= NumEx.BYTE_MAX_VALUE) {
// byte[] r2 = new byte[2];
// r2[0] = B2Type.INT_8B;
byte[] r2 = { B2Type.INT_8B, 1 };
r2[1] = (byte) (v & 0xff);
return r2;
} else if (v >= NumEx.SHORT_MIN_VALUE && v <= NumEx.SHORT_MAX_VALUE) {
// byte[] r2 = new byte[3];
// r2[0] = B2Type.INT_16B;
byte[] r2 = { B2Type.INT_16B, 1, 2 };
r2[1] = (byte) ((v >> 8) & 0xff);
r2[2] = (byte) ((v >> 0) & 0xff);
return r2;
} else {
// byte[] r2 = new byte[5];
// r2[0] = B2Type.INT_32B;
byte[] r2 = { B2Type.INT_32B, 1, 2, 3, 4 };
r2[1] = (byte) ((v >> 24) & 0xff);
r2[2] = (byte) ((v >> 16) & 0xff);
r2[3] = (byte) ((v >> 8) & 0xff);
r2[4] = (byte) ((v >> 0) & 0xff);
return r2;
}
}
}
}
推荐在必要时候使用移位。
- 以上操作经过验证可以直接拿去。
- Owner
breakEval13 - https://github.com/breakEval13