// Copyright 2006, 2007 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry.ioc.internal.services;
import static java.lang.String.format;
import static org.apache.tapestry.ioc.internal.util.CollectionFactory.newMap;
import static org.apache.tapestry.ioc.internal.util.CollectionFactory.newSet;
import java.lang.reflect.Modifier;
import java.util.Formatter;
import java.util.Map;
import java.util.Set;
import javassist.CannotCompileException;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.CtField;
import javassist.CtMethod;
import javassist.NotFoundException;
import org.apache.tapestry.ioc.internal.util.Defense;
import org.apache.tapestry.ioc.internal.util.InternalUtils;
import org.apache.tapestry.ioc.services.ClassFab;
import org.apache.tapestry.ioc.services.ClassFabUtils;
import org.apache.tapestry.ioc.services.MethodIterator;
import org.apache.tapestry.ioc.services.MethodSignature;
import org.slf4j.Logger;
/**
* Implementation of {@link org.apache.tapestry.ioc.services.ClassFab}. Hides, as much as possible,
* the underlying library (Javassist).
*/
public class ClassFabImpl extends AbstractFab implements ClassFab
{
private static final Map<Class, String> DEFAULT_RETURN = newMap();
static
{
DEFAULT_RETURN.put(boolean.class, "false");
DEFAULT_RETURN.put(long.class, "0L");
DEFAULT_RETURN.put(float.class, "0.0f");
DEFAULT_RETURN.put(double.class, "0.0d");
}
/**
* Add fields, methods, and constructors are added, their psuedo-code is appended to this
* description, which is used by toString().
*/
private final StringBuilder _description = new StringBuilder();
private final Formatter _formatter = new Formatter(_description);
private final Set<MethodSignature> _addedSignatures = newSet();
public ClassFabImpl(CtClassSource source, CtClass ctClass, Logger logger)
{
super(source, ctClass, logger);
}
/**
* Returns a representation of the fabricated class, including inheritance, fields,
* constructors, methods and method bodies.
*
* @since 1.1
*/
@Override
public String toString()
{
StringBuilder buffer = new StringBuilder("ClassFab[\n");
try
{
buffer.append(buildClassAndInheritance());
buffer.append(_description.toString());
}
catch (Exception ex)
{
buffer.append(" *** ");
buffer.append(ex);
}
buffer.append("\n]");
return buffer.toString();
}
private String buildClassAndInheritance() throws NotFoundException
{
StringBuilder buffer = new StringBuilder();
buffer.append(Modifier.toString(getCtClass().getModifiers()));
buffer.append(" class ");
buffer.append(getName());
buffer.append(" extends ");
buffer.append(getCtClass().getSuperclass().getName());
buffer.append("\n");
CtClass[] interfaces = getCtClass().getInterfaces();
if (interfaces.length > 0)
{
buffer.append(" implements ");
for (int i = 0; i < interfaces.length; i++)
{
if (i > 0) buffer.append(", ");
buffer.append(interfaces[i].getName());
}
buffer.append("\n\n");
}
return buffer.toString();
}
/**
* Returns the name of the class fabricated by this instance.
*/
String getName()
{
return getCtClass().getName();
}
public void addField(String name, Class type)
{
addField(name, Modifier.PRIVATE, type);
}
public void addField(String name, int modifiers, Class type)
{
_lock.check();
CtClass ctType = convertClass(type);
try
{
CtField field = new CtField(ctType, name, getCtClass());
field.setModifiers(modifiers);
getCtClass().addField(field);
}
catch (CannotCompileException ex)
{
// Have yet to find a way to make this happen!
throw new RuntimeException(ServiceMessages.unableToAddField(name, getCtClass(), ex), ex);
}
_formatter.format("%s %s %s;\n\n", Modifier.toString(modifiers), ClassFabUtils
.toJavaClassName(type), name);
}
public void proxyMethodsToDelegate(Class serviceInterface, String delegateExpression,
String toString)
{
_lock.check();
addInterface(serviceInterface);
MethodIterator mi = new MethodIterator(serviceInterface);
while (mi.hasNext())
{
MethodSignature sig = mi.next();
// ($r) properly handles void methods for us, which keeps this simple.
String body = format("return ($r) %s.%s($$);", delegateExpression, sig.getName());
addMethod(Modifier.PUBLIC, sig, body);
}
if (!mi.getToString()) addToString(toString);
}
public void addToString(String toString)
{
_lock.check();
MethodSignature sig = new MethodSignature(String.class, "toString", null, null);
// TODO: Very simple quoting here, will break down if the string itself contains
// double quotes or various other characters that need escaping.
addMethod(Modifier.PUBLIC, sig, format("return \"%s\";", toString));
}
public void addMethod(int modifiers, MethodSignature ms, String body)
{
_lock.check();
if (_addedSignatures.contains(ms))
throw new RuntimeException(ServiceMessages.duplicateMethodInClass(ms, this));
CtClass ctReturnType = convertClass(ms.getReturnType());
CtClass[] ctParameters = convertClasses(ms.getParameterTypes());
CtClass[] ctExceptions = convertClasses(ms.getExceptionTypes());
CtMethod method = new CtMethod(ctReturnType, ms.getName(), ctParameters, getCtClass());
try
{
method.setModifiers(modifiers);
method.setBody(body);
method.setExceptionTypes(ctExceptions);
getCtClass().addMethod(method);
}
catch (Exception ex)
{
throw new RuntimeException(ServiceMessages.unableToAddMethod(ms, getCtClass(), ex), ex);
}
_addedSignatures.add(ms);
// modifiers, return type, name
_formatter.format("%s %s %s", Modifier.toString(modifiers), ClassFabUtils
.toJavaClassName(ms.getReturnType()), ms.getName());
// parameters, exceptions and body from this:
addMethodDetailsToDescription(ms.getParameterTypes(), ms.getExceptionTypes(), body);
_description.append("\n\n");
}
public void addNoOpMethod(MethodSignature signature)
{
_lock.check();
Class returnType = signature.getReturnType();
if (returnType.equals(void.class))
{
addMethod(Modifier.PUBLIC, signature, "return;");
return;
}
String value = "null";
if (returnType.isPrimitive())
{
value = DEFAULT_RETURN.get(returnType);
if (value == null) value = "0";
}
addMethod(Modifier.PUBLIC, signature, "return " + value + ";");
}
public void addConstructor(Class[] parameterTypes, Class[] exceptions, String body)
{
Defense.notBlank(body, "body");
_lock.check();
CtClass[] ctParameters = convertClasses(parameterTypes);
CtClass[] ctExceptions = convertClasses(exceptions);
try
{
CtConstructor constructor = new CtConstructor(ctParameters, getCtClass());
constructor.setExceptionTypes(ctExceptions);
constructor.setBody(body);
getCtClass().addConstructor(constructor);
}
catch (Exception ex)
{
throw new RuntimeException(ServiceMessages.unableToAddConstructor(getCtClass(), ex), ex);
}
_description.append("public ");
// This isn't quite right; we should strip the package portion off of the name.
// However, fabricated classes are almost always in the "default" package, so
// this is OK.
_description.append(getName());
addMethodDetailsToDescription(parameterTypes, exceptions, body);
_description.append("\n\n");
}
/**
* Adds a listing of method (or constructor) parameters and thrown exceptions, and the body, to
* the description
*
* @param parameterTypes
* types of method parameters, or null
* @param exceptions
* types of throw exceptions, or null
* @param body
* body of method or constructor
*/
private void addMethodDetailsToDescription(Class[] parameterTypes, Class[] exceptions,
String body)
{
_description.append("(");
int count = InternalUtils.size(parameterTypes);
for (int i = 0; i < count; i++)
{
if (i > 0) _description.append(", ");
_description.append(ClassFabUtils.toJavaClassName(parameterTypes[i]));
_description.append(" $");
_description.append(i + 1);
}
_description.append(")");
count = InternalUtils.size(exceptions);
for (int i = 0; i < count; i++)
{
if (i == 0)
_description.append("\n throws ");
else
_description.append(", ");
// Since this can never be an array type, we don't need to use getJavaClassName
_description.append(exceptions[i].getName());
}
_description.append("\n");
_description.append(body);
}
}