implemented JASSIST-170

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@639 30ef5769-5b8d-40dd-aea6-55b5d6557bb3

1 files changed, 84 insertions, 0 deletions

diff --git a/src/main/javassist/CtClass.java b/src/main/javassist/CtClass.java
index 7f115d0d..bcf61e41 100644
--- a/src/main/javassist/CtClass.java
+++ b/src/main/javassist/CtClass.java
@@ -29,6 +29,7 @@ import java.util.Collection;
 import javassist.bytecode.ClassFile;
 import javassist.bytecode.Descriptor;
 import javassist.bytecode.Opcode;
+import javassist.bytecode.SignatureAttribute;
 import javassist.expr.ExprEditor;
 
 /* Note:
@@ -388,6 +389,89 @@ public abstract class CtClass {
     }
 
     /**
+     * Returns the generic signature of the class.
+     *
+     * <p>The generics of Java is implemented by the erasure technique.
+     * After compilation, all type parameters are dropped off from the
+     * main part of a class file.  However, for reflection, the type
+     * parameters are encoded into generic signatures and attached
+     * to a class file.
+     *
+     * @return null if the generic signature is not included.
+     * @see javassist.bytecode.SignatureAttribute#toClassSignature(String)
+     * @see CtMember#getGenericSignature()
+     * @since 3.17
+     */
+    public String getGenericSignature() { return null; }
+
+    /**
+     * Sets the generic signature of the class.
+     *
+     * <p>The generics of Java is implemented by the erasure technique.
+     * After compilation, all type parameters are dropped off from the
+     * main part of a class file.  However, for reflection, the type
+     * parameters must be encoded into generic signatures and attached
+     * to a class file.
+     *
+     * <p>For example,
+     *
+     * <pre>class List<T> {
+     *     T value;
+     *     T get() { return value; }
+     *     void set(T v) { value = v; }
+     * }
+     * </pre>
+     *
+     * <p>this class is generated by the following code:
+     *
+     * <pre>
+     * ClassPool pool = ClassPool.getDefault();
+     * CtClass cc = pool.makeClass("List");
+     * CtClass objectClass = pool.get(CtClass.javaLangObject);
+     * ClassSignature cs = new ClassSignature(
+     *                         new TypeParameter[] { new TypeParameter("T") });
+     * cc.setGenericSignature(cs.encode());    // &lt;T:Ljava/lang/Object;&gt;Ljava/lang/Object;
+     *
+     * CtField f = new CtField(objClass, "value", cc);
+     * TypeVariable tvar = new TypeVariable("T");
+     * f.setGenericSignature(tvar.encode());   // TT;
+     * cc.addField(f);
+     *
+     * CtMethod m = CtNewMethod.make("public Object get(){return value;}", cc);
+     * MethodSignature ms = new MethodSignature(null, null, tvar, null);
+     * m.setGenericSignature(ms.encode());     // ()TT;
+     * cc.addMethod(m);
+     *
+     * CtMethod m2 = CtNewMethod.make("public void set(Object v){value = v;}", cc);
+     * MethodSignature ms2 = new MethodSignature(null, new Type[] { tvar },
+     *                                           new BaseType("void"), null);
+     * m2.setGenericSignature(ms2.encode());   // (TT;)V;
+     * cc.addMethod(m2);
+     *
+     * cc.writeFile();
+     * </pre>
+     *
+     * <p>The generated class file is equivalent to the following:
+     *
+     * <pre>class List {
+     *     Object value;
+     *     Object get() { return value; }
+     *     void set(Object v) { value = v; }
+     * }</pre>
+     *
+     * <p>but it includes generic signatures for the class, the field,
+     * and the methods so that the type variable <code>T</code> can be
+     * accessible through reflection.
+     *
+     * @param sig       a generic signature.
+     * @see javassist.bytecode.SignatureAttribute.ClassSignature#encode()
+     * @see javassist.bytecode.SignatureAttribute.MethodSignature#encode()
+     * @see CtMember#setGenericSignature(String)
+     * @since 3.17
+     */
+    public void setGenericSignature(String sig) { checkModify(); }
+
+    /**
      * Substitutes <code>newName</code> for all occurrences of a class
      * name <code>oldName</code> in the class file.
      *