how to serialize map to byte array by protostuff - protostuff

Question

is any method to serialize java.util.Map to byte array when using protostuff,
I saw there is a MapSchema in the protostuff-collectionsschema.jar file, but don't know how to use it.
can anyone give me some sample code,
thanks in advance.

Answer 1

If you need to serialize and deserialize Map, then you should wrap it as a field into a wrapper class (to create schema).
After that you can serialize/deserialize data to a binary format (or json, if you want human-readable text) with RuntimeSchema.
public class Foo {
private Map<Integer, String> map;
Serialization and deserialization code might look like this:
private final LinkedBuffer BUFFER = LinkedBuffer.allocate();
private final Schema<Foo> SCHEMA = RuntimeSchema.getSchema(Foo.class);
#Test
public void serializeAndDeserialize() throws Exception {
Foo foo = createFooInstance();
byte[] bytes = serialize(foo);
Foo x = deserialize(bytes);
Assert.assertEquals(foo, x);
}
private byte[] serialize(Foo foo) throws java.io.IOException {
return ProtobufIOUtil.toByteArray(foo, SCHEMA, BUFFER);
}
private Foo deserialize(byte[] bytes) {
Foo tmp = SCHEMA.newMessage();
ProtobufIOUtil.mergeFrom(bytes, tmp, SCHEMA);
return tmp;
}
Full source code for this example: RuntimeSchemaUsage.java

Answer 2

You can be in protostuff - collectionschema found in the test code.
public class StringMapSchema<V> extends MapSchema<String,V>
{
/**
* The schema for Map<String,String>
*/
public static final StringMapSchema<String> VALUE_STRING = new StringMapSchema<String>(null)
{
protected void putValueFrom(Input input, MapWrapper<String,String> wrapper,
String key) throws IOException
{
wrapper.put(key, input.readString());
}
protected void writeValueTo(Output output, int fieldNumber, String value,
boolean repeated) throws IOException
{
output.writeString(fieldNumber, value, repeated);
}
protected void transferValue(Pipe pipe, Input input, Output output, int number,
boolean repeated) throws IOException
{
input.transferByteRangeTo(output, true, number, repeated);
}
};
/**
* The schema of the message value.
*/
public final Schema<V> vSchema;
/**
* The pipe schema of the message value.
*/
public final Pipe.Schema<V> vPipeSchema;
public StringMapSchema(Schema<V> vSchema)
{
this(vSchema, null);
}
public StringMapSchema(Schema<V> vSchema, Pipe.Schema<V> vPipeSchema)
{
this.vSchema = vSchema;
this.vPipeSchema = vPipeSchema;
}
protected final String readKeyFrom(Input input, MapWrapper<String,V> wrapper)
throws IOException
{
return input.readString();
}
protected void putValueFrom(Input input, MapWrapper<String,V> wrapper, String key)
throws IOException
{
wrapper.put(key, input.mergeObject(null, vSchema));
}
protected final void writeKeyTo(Output output, int fieldNumber, String value,
boolean repeated) throws IOException
{
output.writeString(fieldNumber, value, repeated);
}
protected void writeValueTo(Output output, int fieldNumber, V value,
boolean repeated) throws IOException
{
output.writeObject(fieldNumber, value, vSchema, repeated);
}
protected void transferKey(Pipe pipe, Input input, Output output, int number,
boolean repeated) throws IOException
{
input.transferByteRangeTo(output, true, number, repeated);
}
protected void transferValue(Pipe pipe, Input input, Output output, int number,
boolean repeated) throws IOException
{
if(vPipeSchema == null)
{
throw new RuntimeException("No pipe schema for value: " +
vSchema.typeClass().getName());
}
output.writeObject(number, pipe, vPipeSchema, repeated);
}
}