jaxws/src/share/classes/com/sun/xml/internal/bind/v2/model/nav/ReflectionNavigator.java - platform/libcore - Git at Google

 /*
  * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Sun designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Sun in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  */
 package com.sun.xml.internal.bind.v2.model.nav;

 import java.lang.reflect.Array;
 import java.lang.reflect.Field;
 import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.GenericDeclaration;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
 import java.lang.reflect.WildcardType;
 import java.util.Arrays;
 import java.util.Collection;

 import com.sun.xml.internal.bind.v2.runtime.Location;

 /**
  * {@link Navigator} implementation for {@code java.lang.reflect}.
  *
  */
 public final class ReflectionNavigator implements Navigator<Type,Class,Field,Method> {
     /**
      * Singleton.
      *
      * Use {@link Navigator#REFLECTION}
      */
     ReflectionNavigator() {}

     public Class getSuperClass(Class clazz) {
         if(clazz==Object.class) return null;
         Class sc = clazz.getSuperclass();
         if(sc==null)    sc=Object.class;        // error recovery
         return sc;
     }

     private static final TypeVisitor<Type,Class> baseClassFinder = new TypeVisitor<Type,Class>() {
         public Type onClass(Class c, Class sup) {
             // t is a raw type
             if(sup==c)
                 return sup;

             Type r;

             Type sc = c.getGenericSuperclass();
             if(sc!=null) {
                 r = visit(sc,sup);
                 if(r!=null)     return r;
             }

             for( Type i : c.getGenericInterfaces() ) {
                 r = visit(i,sup);
                 if(r!=null)  return r;
             }

             return null;
         }

         public Type onParameterizdType(ParameterizedType p, Class sup) {
             Class raw = (Class) p.getRawType();
             if(raw==sup) {
                 // p is of the form sup<...>
                 return p;
             } else {
                 // recursively visit super class/interfaces
                 Type r = raw.getGenericSuperclass();
                 if(r!=null)
                     r = visit(bind(r,raw,p),sup);
                 if(r!=null)
                     return r;
                 for( Type i : raw.getGenericInterfaces() ) {
                     r = visit(bind(i,raw,p),sup);
                     if(r!=null)  return r;
                 }
                 return null;
             }
         }

         public Type onGenericArray(GenericArrayType g, Class sup) {
             // not clear what I should do here
             return null;
         }

         public Type onVariable(TypeVariable v, Class sup) {
             return visit(v.getBounds()[0],sup);
         }

         public Type onWildcard(WildcardType w, Class sup) {
             // not clear what I should do here
             return null;
         }

         /**
          * Replaces the type variables in {@code t} by its actual arguments.
          *
          * @param decl
          *      provides a list of type variables. See {@link GenericDeclaration#getTypeParameters()}
          * @param args
          *      actual arguments. See {@link ParameterizedType#getActualTypeArguments()}
          */
         private Type bind( Type t, GenericDeclaration decl, ParameterizedType args ) {
             return binder.visit(t,new BinderArg(decl,args.getActualTypeArguments()));
         }
     };

     private static class BinderArg {
         final TypeVariable[] params;
         final Type[] args;

         BinderArg(TypeVariable[] params, Type[] args) {
             this.params = params;
             this.args = args;
             assert params.length==args.length;
         }

         public BinderArg( GenericDeclaration decl, Type[] args ) {
             this(decl.getTypeParameters(),args);
         }

         Type replace( TypeVariable v ) {
             for(int i=0; i<params.length; i++)
                 if(params[i]==v)
                     return args[i];
             return v;   // this is a free variable
         }
     }
     private static final TypeVisitor<Type,BinderArg> binder = new TypeVisitor<Type,BinderArg>() {
         public Type onClass(Class c, BinderArg args) {
             return c;
         }

         public Type onParameterizdType(ParameterizedType p, BinderArg args) {
             Type[] params = p.getActualTypeArguments();

             boolean different = false;
             for( int i=0; i<params.length; i++ ) {
                 Type t = params[i];
                 params[i] = visit(t,args);
                 different |= t!=params[i];
             }

             Type newOwner = p.getOwnerType();
             if(newOwner!=null)
                 newOwner = visit(newOwner,args);
             different |= p.getOwnerType()!=newOwner;

             if(!different)  return p;

             return new ParameterizedTypeImpl( (Class<?>)p.getRawType(), params, newOwner );
         }

         public Type onGenericArray(GenericArrayType g, BinderArg types) {
             Type c = visit(g.getGenericComponentType(),types);
             if(c==g.getGenericComponentType())  return g;

             return new GenericArrayTypeImpl(c);
         }

         public Type onVariable(TypeVariable v, BinderArg types) {
             return types.replace(v);
         }

         public Type onWildcard(WildcardType w, BinderArg types) {
             // TODO: this is probably still incorrect
             // bind( "? extends T" ) with T= "? extends Foo" should be "? extends Foo",
             // not "? extends (? extends Foo)"
             Type[] lb = w.getLowerBounds();
             Type[] ub = w.getUpperBounds();
             boolean diff = false;

             for( int i=0; i<lb.length; i++ ) {
                 Type t = lb[i];
                 lb[i] = visit(t,types);
                 diff |= (t!=lb[i]);
             }

             for( int i=0; i<ub.length; i++ ) {
                 Type t = ub[i];
                 ub[i] = visit(t,types);
                 diff |= (t!=ub[i]);
             }

             if(!diff)       return w;

             return new WildcardTypeImpl(lb,ub);
         }
     };


     public Type getBaseClass(Type t, Class sup) {
         return baseClassFinder.visit(t,sup);
     }

     public String getClassName(Class clazz) {
         return clazz.getName();
     }

     public String getTypeName(Type type) {
         if (type instanceof Class) {
             Class c = (Class) type;
             if(c.isArray())
                 return getTypeName(c.getComponentType())+"[]";
             return c.getName();
         }
         return type.toString();
     }

     public String getClassShortName(Class clazz) {
         return clazz.getSimpleName();
     }

     public Collection<? extends Field> getDeclaredFields(Class clazz) {
         return Arrays.asList(clazz.getDeclaredFields());
     }

     public Field getDeclaredField(Class clazz, String fieldName) {
         try {
             return clazz.getDeclaredField(fieldName);
         } catch (NoSuchFieldException e) {
             return null;
         }
     }

     public Collection<? extends Method> getDeclaredMethods(Class clazz) {
         return Arrays.asList(clazz.getDeclaredMethods());
     }

     public Class getDeclaringClassForField(Field field) {
         return field.getDeclaringClass();
     }

     public Class getDeclaringClassForMethod(Method method) {
         return method.getDeclaringClass();
     }

     public Type getFieldType(Field field) {
         return fix(field.getGenericType());
     }

     public String getFieldName(Field field) {
         return field.getName();
     }

     public String getMethodName(Method method) {
         return method.getName();
     }

     public Type getReturnType(Method method) {
         return fix(method.getGenericReturnType());
     }

     public Type[] getMethodParameters(Method method) {
         return method.getGenericParameterTypes();
     }

     public boolean isStaticMethod(Method method) {
         return Modifier.isStatic(method.getModifiers());
     }

     public boolean isSubClassOf(Type sub, Type sup) {
         return erasure(sup).isAssignableFrom(erasure(sub));
     }

     public Class ref(Class c) {
         return c;
     }

     public Class use(Class c) {
         return c;
     }

     public Class asDecl(Type t) {
         return erasure(t);
     }

     public Class asDecl(Class c) {
         return c;
     }


     /**
      * Implements the logic for {@link #erasure(Type)}.
      */
     private static final TypeVisitor<Class,Void> eraser = new TypeVisitor<Class,Void>() {
         public Class onClass(Class c,Void _) {
             return c;
         }

         public Class onParameterizdType(ParameterizedType p,Void _) {
             // TODO: why getRawType returns Type? not Class?
             return visit(p.getRawType(),null);
         }

         public Class onGenericArray(GenericArrayType g,Void _) {
             return Array.newInstance(
                 visit(g.getGenericComponentType(),null),
                 0 ).getClass();
         }

         public Class onVariable(TypeVariable v,Void _) {
             return visit(v.getBounds()[0],null);
         }

         public Class onWildcard(WildcardType w,Void _) {
             return visit(w.getUpperBounds()[0],null);
         }
     };

     /**
      * Returns the runtime representation of the given type.
      *
      * This corresponds to the notion of the erasure in JSR-14.
      *
      * <p>
      * Because of the difference in the way APT and the Java reflection
      * treats primitive type and array type, we can't define this method
      * on {@link Navigator}.
      *
      * <p>
      * It made me realize how difficult it is to define the common navigation
      * layer for two different underlying reflection library. The other way
      * is to throw away the entire parameterization and go to the wrapper approach.
      */
     public <T> Class<T> erasure(Type t) {
         return eraser.visit(t,null);
     }

     public boolean isAbstract(Class clazz) {
         return Modifier.isAbstract(clazz.getModifiers());
     }

     public boolean isFinal(Class clazz) {
         return Modifier.isFinal(clazz.getModifiers());
     }

     /**
      * Returns the {@link Type} object that represents {@code clazz&lt;T1,T2,T3>}.
      */
     public Type createParameterizedType( Class rawType, Type... arguments ) {
         return new ParameterizedTypeImpl(rawType,arguments,null);
     }

     public boolean isArray(Type t) {
         if (t instanceof Class) {
             Class c = (Class) t;
             return c.isArray();
         }
         if(t instanceof GenericArrayType)
             return true;
         return false;
     }

     public boolean isArrayButNotByteArray(Type t) {
         if (t instanceof Class) {
             Class c = (Class) t;
             return c.isArray() && c!=byte[].class;
         }
         if(t instanceof GenericArrayType) {
             t = ((GenericArrayType)t).getGenericComponentType();
             return t!=Byte.TYPE;
         }
         return false;
     }


     public Type getComponentType(Type t) {
         if (t instanceof Class) {
             Class c = (Class) t;
             return c.getComponentType();
         }
         if(t instanceof GenericArrayType)
             return ((GenericArrayType)t).getGenericComponentType();

         throw new IllegalArgumentException();
     }

     public Type getTypeArgument(Type type, int i) {
         if (type instanceof ParameterizedType) {
             ParameterizedType p = (ParameterizedType) type;
             return fix(p.getActualTypeArguments()[i]);
         } else
             throw new IllegalArgumentException();
     }

     public boolean isParameterizedType(Type type) {
         return type instanceof ParameterizedType;
     }

     public boolean isPrimitive(Type type) {
         if (type instanceof Class) {
             Class c = (Class) type;
             return c.isPrimitive();
         }
         return false;
     }

     public Type getPrimitive(Class primitiveType) {
         assert primitiveType.isPrimitive();
         return primitiveType;
     }

     public Location getClassLocation(final Class clazz) {
         return new Location() {
             public String toString() {
                 return clazz.getName();
             }
         };
     }

     public Location getFieldLocation(final Field field) {
         return new Location() {
             public String toString() {
                 return field.toString();
             }
         };
     }

     public Location getMethodLocation(final Method method) {
         return new Location() {
             public String toString() {
                 return method.toString();
             }
         };
     }

     public boolean hasDefaultConstructor(Class c) {
         try {
             c.getDeclaredConstructor();
             return true;
         } catch (NoSuchMethodException e) {
             return false;
         }
     }

     public boolean isStaticField(Field field) {
         return Modifier.isStatic(field.getModifiers());
     }

     public boolean isPublicMethod(Method method) {
         return Modifier.isPublic(method.getModifiers());
     }

     public boolean isPublicField(Field field) {
         return Modifier.isPublic(field.getModifiers());
     }

     public boolean isEnum(Class c) {
         return Enum.class.isAssignableFrom(c);
     }

     public Field[] getEnumConstants(Class clazz) {
         try {
             Object[] values = clazz.getEnumConstants();
             Field[] fields = new Field[values.length];
             for( int i=0; i<values.length; i++ ) {
                 fields[i] = clazz.getField(((Enum)values[i]).name());
             }
             return fields;
         } catch (NoSuchFieldException e) {
             // impossible
             throw new NoSuchFieldError(e.getMessage());
         }
     }

     public Type getVoidType() {
         return Void.class;
     }

     public String getPackageName(Class clazz) {
         String name = clazz.getName();
         int idx = name.lastIndexOf('.');
         if(idx<0)   return "";
         else        return name.substring(0,idx);
     }

     public Class findClass(String className, Class referencePoint) {
         try {
         ClassLoader cl = referencePoint.getClassLoader();
         if(cl==null)  cl = ClassLoader.getSystemClassLoader();
             return cl.loadClass(className);
         } catch (ClassNotFoundException e) {
             return null;
         }
     }

     public boolean isBridgeMethod(Method method) {
         return method.isBridge();
     }

     public boolean isOverriding(Method method, Class base) {
         // this isn't actually correct,
         // as the JLS considers
         // class Derived extends Base<Integer> {
         //   Integer getX() { ... }
         // }
         // class Base<T> {
         //   T getX() { ... }
         // }
         // to be overrided. Handling this correctly needs a careful implementation

         String name = method.getName();
         Class[] params = method.getParameterTypes();

         while(base!=null) {
             try {
                 if(base.getDeclaredMethod(name,params)!=null)
                     return true;
             } catch (NoSuchMethodException e) {
                 // recursively go into the base class
             }

             base = base.getSuperclass();
         }

         return false;
     }

     public boolean isInterface(Class clazz) {
         return clazz.isInterface();
     }

     public boolean isTransient(Field f) {
         return Modifier.isTransient(f.getModifiers());
     }

     public boolean isInnerClass(Class clazz) {
         return clazz.getEnclosingClass()!=null;
     }


     /**
      * JDK 5.0 has a bug of createing {@link GenericArrayType} where it shouldn't.
      * fix that manually to work around the problem.
      *
      * See bug 6202725.
      */
     private Type fix(Type t) {
         if(!(t instanceof GenericArrayType))
             return t;

         GenericArrayType gat = (GenericArrayType) t;
         if(gat.getGenericComponentType() instanceof Class) {
             Class c = (Class) gat.getGenericComponentType();
             return Array.newInstance(c,0).getClass();
         }

         return t;
     }
 }
	/*
	* Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Sun designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Sun in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*/
	package com.sun.xml.internal.bind.v2.model.nav;

	import java.lang.reflect.Array;
	import java.lang.reflect.Field;
	import java.lang.reflect.GenericArrayType;
	import java.lang.reflect.GenericDeclaration;
	import java.lang.reflect.Method;
	import java.lang.reflect.Modifier;
	import java.lang.reflect.ParameterizedType;
	import java.lang.reflect.Type;
	import java.lang.reflect.TypeVariable;
	import java.lang.reflect.WildcardType;
	import java.util.Arrays;
	import java.util.Collection;

	import com.sun.xml.internal.bind.v2.runtime.Location;

	/**
	* {@link Navigator} implementation for {@code java.lang.reflect}.
	*
	*/
	public final class ReflectionNavigator implements Navigator<Type,Class,Field,Method> {
	/**
	* Singleton.
	*
	* Use {@link Navigator#REFLECTION}
	*/
	ReflectionNavigator() {}

	public Class getSuperClass(Class clazz) {
	if(clazz==Object.class) return null;
	Class sc = clazz.getSuperclass();
	if(sc==null) sc=Object.class; // error recovery
	return sc;
	}

	private static final TypeVisitor<Type,Class> baseClassFinder = new TypeVisitor<Type,Class>() {
	public Type onClass(Class c, Class sup) {
	// t is a raw type
	if(sup==c)
	return sup;

	Type r;

	Type sc = c.getGenericSuperclass();
	if(sc!=null) {
	r = visit(sc,sup);
	if(r!=null) return r;
	}

	for( Type i : c.getGenericInterfaces() ) {
	r = visit(i,sup);
	if(r!=null) return r;
	}

	return null;
	}

	public Type onParameterizdType(ParameterizedType p, Class sup) {
	Class raw = (Class) p.getRawType();
	if(raw==sup) {
	// p is of the form sup<...>
	return p;
	} else {
	// recursively visit super class/interfaces
	Type r = raw.getGenericSuperclass();
	if(r!=null)
	r = visit(bind(r,raw,p),sup);
	if(r!=null)
	return r;
	for( Type i : raw.getGenericInterfaces() ) {
	r = visit(bind(i,raw,p),sup);
	if(r!=null) return r;
	}
	return null;
	}
	}

	public Type onGenericArray(GenericArrayType g, Class sup) {
	// not clear what I should do here
	return null;
	}

	public Type onVariable(TypeVariable v, Class sup) {
	return visit(v.getBounds()[0],sup);
	}

	public Type onWildcard(WildcardType w, Class sup) {
	// not clear what I should do here
	return null;
	}

	/**
	* Replaces the type variables in {@code t} by its actual arguments.
	*
	* @param decl
	* provides a list of type variables. See {@link GenericDeclaration#getTypeParameters()}
	* @param args
	* actual arguments. See {@link ParameterizedType#getActualTypeArguments()}
	*/
	private Type bind( Type t, GenericDeclaration decl, ParameterizedType args ) {
	return binder.visit(t,new BinderArg(decl,args.getActualTypeArguments()));
	}
	};

	private static class BinderArg {
	final TypeVariable[] params;
	final Type[] args;

	BinderArg(TypeVariable[] params, Type[] args) {
	this.params = params;
	this.args = args;
	assert params.length==args.length;
	}

	public BinderArg( GenericDeclaration decl, Type[] args ) {
	this(decl.getTypeParameters(),args);
	}

	Type replace( TypeVariable v ) {
	for(int i=0; i<params.length; i++)
	if(params[i]==v)
	return args[i];
	return v; // this is a free variable
	}
	}
	private static final TypeVisitor<Type,BinderArg> binder = new TypeVisitor<Type,BinderArg>() {
	public Type onClass(Class c, BinderArg args) {
	return c;
	}

	public Type onParameterizdType(ParameterizedType p, BinderArg args) {
	Type[] params = p.getActualTypeArguments();

	boolean different = false;
	for( int i=0; i<params.length; i++ ) {
	Type t = params[i];
	params[i] = visit(t,args);
	different \|= t!=params[i];
	}

	Type newOwner = p.getOwnerType();
	if(newOwner!=null)
	newOwner = visit(newOwner,args);
	different \|= p.getOwnerType()!=newOwner;

	if(!different) return p;

	return new ParameterizedTypeImpl( (Class<?>)p.getRawType(), params, newOwner );
	}

	public Type onGenericArray(GenericArrayType g, BinderArg types) {
	Type c = visit(g.getGenericComponentType(),types);
	if(c==g.getGenericComponentType()) return g;

	return new GenericArrayTypeImpl(c);
	}

	public Type onVariable(TypeVariable v, BinderArg types) {
	return types.replace(v);
	}

	public Type onWildcard(WildcardType w, BinderArg types) {
	// TODO: this is probably still incorrect
	// bind( "? extends T" ) with T= "? extends Foo" should be "? extends Foo",
	// not "? extends (? extends Foo)"
	Type[] lb = w.getLowerBounds();
	Type[] ub = w.getUpperBounds();
	boolean diff = false;

	for( int i=0; i<lb.length; i++ ) {
	Type t = lb[i];
	lb[i] = visit(t,types);
	diff \|= (t!=lb[i]);
	}

	for( int i=0; i<ub.length; i++ ) {
	Type t = ub[i];
	ub[i] = visit(t,types);
	diff \|= (t!=ub[i]);
	}

	if(!diff) return w;

	return new WildcardTypeImpl(lb,ub);
	}
	};


	public Type getBaseClass(Type t, Class sup) {
	return baseClassFinder.visit(t,sup);
	}

	public String getClassName(Class clazz) {
	return clazz.getName();
	}

	public String getTypeName(Type type) {
	if (type instanceof Class) {
	Class c = (Class) type;
	if(c.isArray())
	return getTypeName(c.getComponentType())+"[]";
	return c.getName();
	}
	return type.toString();
	}

	public String getClassShortName(Class clazz) {
	return clazz.getSimpleName();
	}

	public Collection<? extends Field> getDeclaredFields(Class clazz) {
	return Arrays.asList(clazz.getDeclaredFields());
	}

	public Field getDeclaredField(Class clazz, String fieldName) {
	try {
	return clazz.getDeclaredField(fieldName);
	} catch (NoSuchFieldException e) {
	return null;
	}
	}

	public Collection<? extends Method> getDeclaredMethods(Class clazz) {
	return Arrays.asList(clazz.getDeclaredMethods());
	}

	public Class getDeclaringClassForField(Field field) {
	return field.getDeclaringClass();
	}

	public Class getDeclaringClassForMethod(Method method) {
	return method.getDeclaringClass();
	}

	public Type getFieldType(Field field) {
	return fix(field.getGenericType());
	}

	public String getFieldName(Field field) {
	return field.getName();
	}

	public String getMethodName(Method method) {
	return method.getName();
	}

	public Type getReturnType(Method method) {
	return fix(method.getGenericReturnType());
	}

	public Type[] getMethodParameters(Method method) {
	return method.getGenericParameterTypes();
	}

	public boolean isStaticMethod(Method method) {
	return Modifier.isStatic(method.getModifiers());
	}

	public boolean isSubClassOf(Type sub, Type sup) {
	return erasure(sup).isAssignableFrom(erasure(sub));
	}

	public Class ref(Class c) {
	return c;
	}

	public Class use(Class c) {
	return c;
	}

	public Class asDecl(Type t) {
	return erasure(t);
	}

	public Class asDecl(Class c) {
	return c;
	}


	/**
	* Implements the logic for {@link #erasure(Type)}.
	*/
	private static final TypeVisitor<Class,Void> eraser = new TypeVisitor<Class,Void>() {
	public Class onClass(Class c,Void _) {
	return c;
	}

	public Class onParameterizdType(ParameterizedType p,Void _) {
	// TODO: why getRawType returns Type? not Class?
	return visit(p.getRawType(),null);
	}

	public Class onGenericArray(GenericArrayType g,Void _) {
	return Array.newInstance(
	visit(g.getGenericComponentType(),null),
	0 ).getClass();
	}

	public Class onVariable(TypeVariable v,Void _) {
	return visit(v.getBounds()[0],null);
	}

	public Class onWildcard(WildcardType w,Void _) {
	return visit(w.getUpperBounds()[0],null);
	}
	};

	/**
	* Returns the runtime representation of the given type.
	*
	* This corresponds to the notion of the erasure in JSR-14.
	*
	* <p>
	* Because of the difference in the way APT and the Java reflection
	* treats primitive type and array type, we can't define this method
	* on {@link Navigator}.
	*
	* <p>
	* It made me realize how difficult it is to define the common navigation
	* layer for two different underlying reflection library. The other way
	* is to throw away the entire parameterization and go to the wrapper approach.
	*/
	public <T> Class<T> erasure(Type t) {
	return eraser.visit(t,null);
	}

	public boolean isAbstract(Class clazz) {
	return Modifier.isAbstract(clazz.getModifiers());
	}

	public boolean isFinal(Class clazz) {
	return Modifier.isFinal(clazz.getModifiers());
	}

	/**
	* Returns the {@link Type} object that represents {@code clazz<T1,T2,T3>}.
	*/
	public Type createParameterizedType( Class rawType, Type... arguments ) {
	return new ParameterizedTypeImpl(rawType,arguments,null);
	}

	public boolean isArray(Type t) {
	if (t instanceof Class) {
	Class c = (Class) t;
	return c.isArray();
	}
	if(t instanceof GenericArrayType)
	return true;
	return false;
	}

	public boolean isArrayButNotByteArray(Type t) {
	if (t instanceof Class) {
	Class c = (Class) t;
	return c.isArray() && c!=byte[].class;
	}
	if(t instanceof GenericArrayType) {
	t = ((GenericArrayType)t).getGenericComponentType();
	return t!=Byte.TYPE;
	}
	return false;
	}


	public Type getComponentType(Type t) {
	if (t instanceof Class) {
	Class c = (Class) t;
	return c.getComponentType();
	}
	if(t instanceof GenericArrayType)
	return ((GenericArrayType)t).getGenericComponentType();

	throw new IllegalArgumentException();
	}

	public Type getTypeArgument(Type type, int i) {
	if (type instanceof ParameterizedType) {
	ParameterizedType p = (ParameterizedType) type;
	return fix(p.getActualTypeArguments()[i]);
	} else
	throw new IllegalArgumentException();
	}

	public boolean isParameterizedType(Type type) {
	return type instanceof ParameterizedType;
	}

	public boolean isPrimitive(Type type) {
	if (type instanceof Class) {
	Class c = (Class) type;
	return c.isPrimitive();
	}
	return false;
	}

	public Type getPrimitive(Class primitiveType) {
	assert primitiveType.isPrimitive();
	return primitiveType;
	}

	public Location getClassLocation(final Class clazz) {
	return new Location() {
	public String toString() {
	return clazz.getName();
	}
	};
	}

	public Location getFieldLocation(final Field field) {
	return new Location() {
	public String toString() {
	return field.toString();
	}
	};
	}

	public Location getMethodLocation(final Method method) {
	return new Location() {
	public String toString() {
	return method.toString();
	}
	};
	}

	public boolean hasDefaultConstructor(Class c) {
	try {
	c.getDeclaredConstructor();
	return true;
	} catch (NoSuchMethodException e) {
	return false;
	}
	}

	public boolean isStaticField(Field field) {
	return Modifier.isStatic(field.getModifiers());
	}

	public boolean isPublicMethod(Method method) {
	return Modifier.isPublic(method.getModifiers());
	}

	public boolean isPublicField(Field field) {
	return Modifier.isPublic(field.getModifiers());
	}

	public boolean isEnum(Class c) {
	return Enum.class.isAssignableFrom(c);
	}

	public Field[] getEnumConstants(Class clazz) {
	try {
	Object[] values = clazz.getEnumConstants();
	Field[] fields = new Field[values.length];
	for( int i=0; i<values.length; i++ ) {
	fields[i] = clazz.getField(((Enum)values[i]).name());
	}
	return fields;
	} catch (NoSuchFieldException e) {
	// impossible
	throw new NoSuchFieldError(e.getMessage());
	}
	}

	public Type getVoidType() {
	return Void.class;
	}

	public String getPackageName(Class clazz) {
	String name = clazz.getName();
	int idx = name.lastIndexOf('.');
	if(idx<0) return "";
	else return name.substring(0,idx);
	}

	public Class findClass(String className, Class referencePoint) {
	try {
	ClassLoader cl = referencePoint.getClassLoader();
	if(cl==null) cl = ClassLoader.getSystemClassLoader();
	return cl.loadClass(className);
	} catch (ClassNotFoundException e) {
	return null;
	}
	}

	public boolean isBridgeMethod(Method method) {
	return method.isBridge();
	}

	public boolean isOverriding(Method method, Class base) {
	// this isn't actually correct,
	// as the JLS considers
	// class Derived extends Base<Integer> {
	// Integer getX() { ... }
	// }
	// class Base<T> {
	// T getX() { ... }
	// }
	// to be overrided. Handling this correctly needs a careful implementation

	String name = method.getName();
	Class[] params = method.getParameterTypes();

	while(base!=null) {
	try {
	if(base.getDeclaredMethod(name,params)!=null)
	return true;
	} catch (NoSuchMethodException e) {
	// recursively go into the base class
	}

	base = base.getSuperclass();
	}

	return false;
	}

	public boolean isInterface(Class clazz) {
	return clazz.isInterface();
	}

	public boolean isTransient(Field f) {
	return Modifier.isTransient(f.getModifiers());
	}

	public boolean isInnerClass(Class clazz) {
	return clazz.getEnclosingClass()!=null;
	}


	/**
	* JDK 5.0 has a bug of createing {@link GenericArrayType} where it shouldn't.
	* fix that manually to work around the problem.
	*
	* See bug 6202725.
	*/
	private Type fix(Type t) {
	if(!(t instanceof GenericArrayType))
	return t;

	GenericArrayType gat = (GenericArrayType) t;
	if(gat.getGenericComponentType() instanceof Class) {
	Class c = (Class) gat.getGenericComponentType();
	return Array.newInstance(c,0).getClass();
	}

	return t;
	}
	}