Add Object allocators #3

Author: Bethibande

core/src/main/java/de/bethibande/serial/Deserializer.java

@@ -1,11 +1,21 @@
 package de.bethibande.serial;
 
+import de.bethibande.serial.allocation.ObjectAllocator;
+
 public interface Deserializer<T> {
 
     boolean isBound();
 
     Deserializer<T> bind(final Reader reader);
 
+    Deserializer<T> withAllocator(final ObjectAllocator<T> allocator);
+
+    ObjectAllocator<T> allocator();
+
+    default T read() {
+        return read(allocator().allocate());
+    }
+
     T read(final T target);
 
 }

core/src/main/java/de/bethibande/serial/allocation/ObjectAllocator.java

@@ -0,0 +1,12 @@
+package de.bethibande.serial.allocation;
+
+@FunctionalInterface
+public interface ObjectAllocator<T> {
+
+    static <T> ObjectAllocator<T> ofStaticValue(final T instance) {
+        return () -> instance;
+    }
+
+    T allocate();
+
+}

core/src/main/java/de/bethibande/serial/allocation/ThreadLocalObjectAllocator.java

@@ -0,0 +1,22 @@
+package de.bethibande.serial.allocation;
+
+/**
+ * A thread-safe object allocator implementation that uses {@link ThreadLocal} to provide
+ * a unique instance of the allocated object per thread.
+ *
+ * @param <T> the type of object to be allocated
+ */
+public class ThreadLocalObjectAllocator<T> implements ObjectAllocator<T> {
+
+    private final ThreadLocal<T> holder;
+
+    public ThreadLocalObjectAllocator(final ObjectAllocator<T> allocator) {
+        this.holder = ThreadLocal.withInitial(allocator::allocate);
+    }
+
+    @Override
+    public T allocate() {
+        return holder.get();
+    }
+
+}

core/src/main/java/de/bethibande/serial/impl/AbstractDeserializer.java

@@ -2,10 +2,12 @@
 
 import de.bethibande.serial.Deserializer;
 import de.bethibande.serial.Reader;
+import de.bethibande.serial.allocation.ObjectAllocator;
 
 public abstract class AbstractDeserializer<T> implements Deserializer<T> {
 
     protected Reader reader;
+    protected ObjectAllocator<T> allocator;
 
     @Override
     public boolean isBound() {
@@ -17,4 +19,15 @@ public Deserializer<T> bind(final Reader reader) {
         this.reader = reader;
         return this;
     }
+
+    @Override
+    public Deserializer<T> withAllocator(final ObjectAllocator<T> allocator) {
+        this.allocator = allocator;
+        return this;
+    }
+
+    @Override
+    public ObjectAllocator<T> allocator() {
+        return allocator;
+    }
 }