refactor: rename InvokeConfig to RunnableConfig

work on #20

core-jdk8/src/main/java/org/bsc/langgraph4j/serializer/MapSerializer.java

@@ -0,0 +1,73 @@
+package org.bsc.langgraph4j.serializer;
+
+import lombok.extern.slf4j.Slf4j;
+
+import java.io.*;
+import java.util.HashMap;
+import java.util.Map;
+
+@Slf4j
+public class StateSerializer implements Serializer<Map<String,Object>> {
+    public static final StateSerializer INSTANCE = new StateSerializer();
+    private StateSerializer() {}
+
+    @Override
+    public void write(Map<String,Object> object, ObjectOutput out) throws IOException {
+        try( ByteArrayOutputStream baos = new ByteArrayOutputStream() ) {
+            int actualSize = 0;
+
+            final ObjectOutputStream tupleStream = new ObjectOutputStream( baos );
+            for( Map.Entry<String,Object> e : object.entrySet() ) {
+                try {
+                    tupleStream.writeUTF(e.getKey());
+                    tupleStream.writeObject(e.getValue());
+                    ++actualSize;
+                } catch (IOException ex) {
+                    log.error( "Error writing state key '{}' - {}", e.getKey(), ex.getMessage() );
+                    throw ex;
+                }
+            }
+
+            out.writeInt( object.size() );
+            out.writeInt( actualSize ); // actual size
+            byte[] data = baos.toByteArray();
+            out.writeInt( data.length );
+            out.write( data );
+
+        }
+
+    }
+
+    @Override
+    public Map<String, Object> read(ObjectInput in) throws IOException, ClassNotFoundException {
+        Map<String, Object> data = new HashMap<>();
+
+        int expectedSize = in.readInt();
+        int actualSize = in.readInt();
+        if( expectedSize > 0 && actualSize > 0 ) {
+
+            if( expectedSize != actualSize ) {
+                final String message = String.format( "Deserialize State: Expected size %d and actual size %d do not match!", expectedSize, actualSize ) ;
+                log.error( message ) ;
+                throw new IOException( message ) ;
+            }
+
+            int byteLen = in.readInt();
+            byte[] bytes = new byte[byteLen];
+            in.readFully(bytes);
+
+            try( ByteArrayInputStream bais = new ByteArrayInputStream( bytes ) ) {
+                ObjectInputStream ois = new ObjectInputStream( bais );
+
+                for( int i = 0; i < actualSize; i++ ) {
+                    String key = ois.readUTF();
+                    Object value = ois.readObject();
+                    data.put(key, value);
+                }
+            }
+
+        }
+        return data;
+    }
+
+}

core-jdk8/src/main/java/org/bsc/langgraph4j/state/StateSnapshot.java

@@ -0,0 +1,2 @@
+package org.bsc.langgraph4j.state;public class StateSnapshot {
+}