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Add usage examples
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‎msgpack-core/src/main/java/org/msgpack/core/example/MessagePackExample.java‎

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package org.msgpack.core.example;
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import org.msgpack.core.*;
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import org.msgpack.core.buffer.MessageBuffer;
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import org.msgpack.value.*;
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import org.msgpack.value.holder.FloatHolder;
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import org.msgpack.value.holder.IntegerHolder;
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import org.msgpack.value.holder.ValueHolder;
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import java.io.*;
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import java.math.BigInteger;
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import java.nio.ByteBuffer;
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import java.nio.charset.CodingErrorAction;
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import java.util.Random;
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/**
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* This class describes the usage of MessagePack v07
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*/
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public class MessagePackExample {
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/**
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* Basic usage example
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* @throws IOException
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*/
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public static void basicUsage() throws IOException {
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// Serialize with MessagePacker
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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MessagePacker packer = MessagePackFactory.newDefaultPacker(out);
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packer
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.packInt(1)
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.packString("leo")
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.packArrayHeader(2)
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.packString("xxx-xxxx")
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.packString("yyy-yyyy");
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packer.close();
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// Deserialize with MessageUnpacker
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MessageUnpacker unpacker = MessagePackFactory.newDefaultUnpacker(out.toByteArray());
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int id = unpacker.unpackInt(); // 1
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String name = unpacker.unpackString(); // "leo"
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int numPhones = unpacker.unpackArrayHeader(); // 2
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String[] phones = new String[numPhones];
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for(int i=0; i < numPhones; ++i) {
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phones[i] = unpacker.unpackString(); // phones = {"xxx-xxxx", "yyy-yyyy"}
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}
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unpacker.close();
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System.out.println(String.format("id:%d, name:%s, phone:[%s]", id, name, join(phones)));
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}
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private static String join(String[] in) {
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StringBuilder s = new StringBuilder();
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for(int i=0; i<in.length; ++i) {
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if(i > 0) {
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s.append(", ");
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}
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s.append(in[i]);
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}
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return s.toString();
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}
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/**
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* Packing various types of data
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* @throws IOException
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*/
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public static void packer() throws IOException {
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// Create a MesagePacker (encoder) instance
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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MessagePacker packer = MessagePackFactory.newDefaultPacker(out);
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// pack (encode) primitive values in message pack format
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packer.packBoolean(true);
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packer.packShort((short) 34);
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packer.packInt(1);
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packer.packLong(33000000000L);
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packer.packFloat(0.1f);
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packer.packDouble(3.14159263);
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packer.packByte((byte) 0x80);
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packer.packNil();
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// pack strings (in UTF-8)
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packer.packString("hello message pack!");
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// [Advanced] write a raw UTF-8 string
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byte[] s = "utf-8 strings".getBytes(MessagePack.UTF8);
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packer.packRawStringHeader(s.length);
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packer.writePayload(s);
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// pack arrays
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int[] arr = new int[]{3, 5, 1, 0, -1, 255};
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packer.packArrayHeader(arr.length);
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for(int v : arr) {
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packer.packInt(v);
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}
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// pack map (key -> value) elements
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packer.packMapHeader(2); // the number of (key, value) pairs
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// Put "apple" -> 1
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packer.packString("apple");
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packer.packInt(1);
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// Put "banana" -> 2
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packer.packString("banana");
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packer.packInt(2);
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// pack binary data
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byte[] ba = new byte[]{1, 2, 3, 4};
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packer.packBinaryHeader(ba.length);
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packer.writePayload(ba);
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// Write ext type data: https://github.com/msgpack/msgpack/blob/master/spec.md#ext-format-family
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byte[] extData = "custom data type".getBytes(MessagePack.UTF8);
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packer.packExtendedTypeHeader(1, 10); // type number [0, 127], data byte length
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packer.writePayload(extData);
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// Succinct syntax for packing
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packer
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.packInt(1)
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.packString("leo")
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.packArrayHeader(2)
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.packString("xxx-xxxx")
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.packString("yyy-yyyy");
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// [Advanced] ByteBuffer
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ByteBuffer.wrap(new byte[] {'b', 'i', 'n', 'a', 'r', 'y', 'd', 'a', 't', 'a'});
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}
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/**
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* An example of reading and writing MessagePack data
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* @throws IOException
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*/
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public static void readAndWriteFile() throws IOException {
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File tempFile = File.createTempFile("target/tmp", ".txt");
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tempFile.deleteOnExit();
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// Write packed data to a file. No need exists to wrap the file stream with BufferedOutputStream, since MessagePacker has its own buffer
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MessagePacker packer = MessagePackFactory.newDefaultPacker(new FileOutputStream(tempFile));
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packer.packInt(1);
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packer.packString("Hello Message Pack!");
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packer.packArrayHeader(2).packFloat(0.1f).packDouble(0.342);
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packer.close();
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// Read packed data from a file. No need exists to wrap the file stream with an buffer
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MessageUnpacker unpacker = MessagePackFactory.newDefaultUnpacker(new FileInputStream(tempFile));
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while(unpacker.hasNext()) {
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// [Advanced] You can check the detailed data format with getNextFormat()
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// Here is a list of message pack data format: https://github.com/msgpack/msgpack/blob/master/spec.md#overview
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MessageFormat format = unpacker.getNextFormat();
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// Alternatively you can use ValueHolder to extract a value of any type
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// NOTE: Value interface is in a preliminary state, so the following code might change in future releases
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ValueHolder v = new ValueHolder();
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format = unpacker.unpackValue(v);
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switch(format.getValueType()) {
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case NIL:
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Value nil = v.get();
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nil.isNil(); // true
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System.out.println("read nil");
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break;
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case BOOLEAN:
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boolean b = v.get().asBoolean().toBoolean();
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System.out.println("read boolean: " + b);
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break;
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case INTEGER:
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IntegerHolder ih = v.getIntegerHolder();
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if(ih.isValidInt()) { // int range check [-2^31-1, 2^31-1]
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int i = ih.asInt();
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System.out.println("read int: " + i);
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}
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else {
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long l = ih.asLong();
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System.out.println("read long: " + l);
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}
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break;
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case FLOAT:
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FloatHolder fh = v.getFloatHolder();
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float f = fh.toFloat(); // read as float
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double d = fh.toDouble(); // read as double
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System.out.println("read float: " + d);
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break;
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case STRING:
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String s = v.get().asString().toString();
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System.out.println("read string: " + s);
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break;
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case BINARY:
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// Message buffer is an efficient byte buffer
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MessageBuffer mb = v.get().asBinary().toMessageBuffer();
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System.out.println("read binary: " + mb.toHexString(0, mb.size()));
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break;
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case ARRAY:
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ArrayValue arr = v.get().asArrayValue();
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for(ValueRef a : arr) {
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System.out.println("read array element: " + a);
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}
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break;
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case EXTENDED:
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ExtendedValue ev = v.get().asExtended();
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int extType = ev.getExtType();
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byte[] extValue = ev.toByteArray();
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break;
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}
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}
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}
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/**
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* Example of using custom MessagePack configuration
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* @throws IOException
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*/
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public static void configuration() throws IOException {
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// Build a conifiguration
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MessagePack.Config config = new MessagePack.ConfigBuilder()
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.onMalFormedInput(CodingErrorAction.REPLACE) // Drop malformed and unmappable UTF-8 characters
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.onUnmappableCharacter(CodingErrorAction.REPLACE)
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.packerBufferSize(8192 * 2)
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.build();
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// Create a factory that uses this configuration
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MessagePackFactory mf = new MessagePackFactory(config);
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// Pack data
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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MessagePacker packer = mf.newPacker(out);
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packer.packInt(10);
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packer.packBoolean(true);
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packer.close();
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// Unpack data
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byte[] packedData = out.toByteArray();
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MessageUnpacker unpacker = mf.newUnpacker(packedData);
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int i = unpacker.unpackInt(); // 10
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boolean b = unpacker.unpackBoolean(); // true
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unpacker.close();
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}
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}

‎msgpack-core/src/test/scala/org/msgpack/core/example/MessagePackExampleTest.scala‎

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package org.msgpack.core.example
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import org.msgpack.core.MessagePackSpec
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import org.scalatest.FunSuite
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/**
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*
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*/
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class MessagePackExampleTest extends MessagePackSpec {
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"example" should {
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"have basic usage" in {
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MessagePackExample.basicUsage()
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}
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"have packer usage" in {
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MessagePackExample.packer()
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}
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"have file read/write example" in {
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MessagePackExample.readAndWriteFile();
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}
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"have configuration example" in {
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MessagePackExample.configuration();
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}
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}
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}

‎version.sbt‎

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version in ThisBuild := "0.7.0-M5-SNAPSHOT"
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version in ThisBuild := "0.7.0-p1"

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