com.schooner.MemCached.command.RetrievalCommand Maven / Gradle / Ivy
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package com.schooner.MemCached.command;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Arrays;
import com.schooner.MemCached.AscIIUDPClient;
import com.schooner.MemCached.MemcachedItem;
import com.schooner.MemCached.NativeHandler;
import com.schooner.MemCached.SchoonerSockIO;
import com.schooner.MemCached.TransCoder;
import com.weicoder.extend.Logs;
/**
* Retrieve a item from memcached server.
*
* @author Meng Li
* @since 2.5.0
* @see com.schooner.MemCached.command.RetrievalCommand
*/
public class RetrievalCommand extends Command {
private static final byte[] B_END = "END\r\n".getBytes();
private static final byte[] B_VALUE = "VALUE ".getBytes();
private String key;
private String cmd;
/**
* request: "get *\r\n" or "gets *\r\n" response: "[item]*END\r\n" item: "VALUE []\r\n\r\n"
*
* @param get or gets
* @param key
* @param hashCode
*/
public RetrievalCommand(String cmd, String key) {
this.key = key;
this.cmd = cmd;
StringBuilder command = new StringBuilder(cmd).append(DELIMITER).append(key).append(RETURN);
textLine = command.toString().getBytes();
}
public class Value {
public int flags;
public int bytes;
public long casUnique;
public byte[] dataBlock;
}
public class ResponseParser {
public Value retvalue = null;
public void exec(byte[] res) throws IOException {
ByteArrayInputStream stream = new ByteArrayInputStream(res);
StringBuilder sb = new StringBuilder();
byte[] end = new byte[5];
byte next;
int length = 0;
// check if it is the end.
stream.mark(0);
stream.read(end);
if (Arrays.equals(end, B_END)) {
return;
}
stream.reset();
Value value = new Value();
// skip "VALUE "
stream.skip(B_VALUE.length + key.length() + 1);
// get the length of and build it.
length = 0;
while ((next = (byte) stream.read()) != AscIIUDPClient.B_DELIMITER) {
length++;
sb.append((char) next);
}
try {
value.flags = Integer.valueOf(sb.toString());
} catch (NumberFormatException e) {
retvalue = null;
return;
}
sb.delete(0, length);
// get the length of and build it.
length = 0;
while (((next = (byte) stream.read()) != AscIIUDPClient.B_DELIMITER) && (next != B_RETURN)) {
length++;
sb.append((char) next);
}
try {
value.bytes = Integer.valueOf(sb.toString());
} catch (NumberFormatException e) {
retvalue = null;
return;
}
sb.delete(0, length);
if (cmd.equals("gets")) {
// if gets then get the length of and build it.
length = 0;
while ((next = (byte) stream.read()) != B_RETURN) {
length++;
sb.append((char) next);
}
try {
value.casUnique = Long.valueOf(sb.toString());
} catch (NumberFormatException e) {
retvalue = null;
return;
}
sb.delete(0, length);
}
// skip "\n"
stream.skip(1);
// build datablock
value.dataBlock = new byte[value.bytes];
stream.read(value.dataBlock);
// skip "\r\n"
stream.skip(2);
// check if it is the end.
stream.mark(0);
stream.read(end);
if (Arrays.equals(end, B_END)) {
retvalue = value;
}
}
}
public MemcachedItem response(SchoonerSockIO sock, TransCoder transCoder, short rid) throws IOException {
byte[] res = sock.getResponse(rid);
MemcachedItem item = new MemcachedItem();
if (res == null)
return item;
ResponseParser parser = new ResponseParser();
parser.exec(res);
if (parser.retvalue != null) {
Value value = parser.retvalue;
if (cmd.equals("gets")) {
item.casUnique = value.casUnique;
}
try {
if (NativeHandler.isHandled(value.flags)) {
item.value = NativeHandler.decode(value.dataBlock, value.flags);
} else if (transCoder != null) {
// decode object with default transcoder.
item.value = transCoder.decode(new ByteArrayInputStream(value.dataBlock));
}
} catch (IOException e) {
Logs.error("error happend in decoding the object");
throw e;
}
return item;
}
// TODO: for get multi only.
return item;
}
}