corejava第10版

corejava第10版/v2ch08/compiler/MapClassLoader.java

@@ -0,0 +1,28 @@
+package compiler;
+
+import java.util.*;
+
+/**
+ * A class loader that loads classes from a map whose keys are class names and whose values are byte
+ * code arrays.
+ * @version 1.00 2007-11-02
+ * @author Cay Horstmann
+ */
+public class MapClassLoader extends ClassLoader
+{
+   private Map<String, byte[]> classes;
+
+   public MapClassLoader(Map<String, byte[]> classes)
+   {
+      this.classes = classes;
+   }
+
+   protected Class<?> findClass(String name) throws ClassNotFoundException
+   {
+      byte[] classBytes = classes.get(name);
+      if (classBytes == null) throw new ClassNotFoundException(name);
+      Class<?> cl = defineClass(name, classBytes, 0, classBytes.length);
+      if (cl == null) throw new ClassNotFoundException(name);
+      return cl;
+   }
+}