org.iternine.jeppetto.enhance.TemplateHelper Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2014 Jeppetto and Jonathan Thompson
*
* 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.iternine.jeppetto.enhance;
import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.CtField;
import javassist.CtMethod;
import javassist.CtNewConstructor;
import javassist.CtNewMethod;
import javassist.NotFoundException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
public class TemplateHelper {
//-------------------------------------------------------------
// Variables - Private
//-------------------------------------------------------------
private static AtomicInteger COUNT = new AtomicInteger(1); // A counter to uniquify enhanced class names, starts at 1.
private static Map, Class> PRIMITIVE_WRAPPERS;
private String className;
private String superClassName;
private List interfaceNames = new ArrayList();
private CtClass thisClass;
private ClassPool pool;
private static Logger logger = LoggerFactory.getLogger(TemplateHelper.class);
//-------------------------------------------------------------
// Constructors
//-------------------------------------------------------------
static {
PRIMITIVE_WRAPPERS = new HashMap, Class>();
PRIMITIVE_WRAPPERS.put(boolean.class, Boolean.class);
PRIMITIVE_WRAPPERS.put(byte.class, Byte.class);
PRIMITIVE_WRAPPERS.put(short.class, Short.class);
PRIMITIVE_WRAPPERS.put(int.class, Integer.class);
PRIMITIVE_WRAPPERS.put(long.class, Long.class);
PRIMITIVE_WRAPPERS.put(float.class, Float.class);
PRIMITIVE_WRAPPERS.put(double.class, Double.class);
PRIMITIVE_WRAPPERS.put(void.class, Void.class);
}
public TemplateHelper(ClassPool pool) {
this.pool = pool;
}
//-------------------------------------------------------------
// Methods - Public
//-------------------------------------------------------------
public TemplateHelper cls(String name) {
String newClassName = name + "$" + COUNT.getAndIncrement();
thisClass = pool.makeClass(newClassName);
className = thisClass.getSimpleName();
return this;
}
public String clsName() {
return className;
}
public TemplateHelper ext(CtClass superClass)
throws CannotCompileException {
superClassName = superClass.getName();
thisClass.setSuperclass(superClass);
return this;
}
public TemplateHelper impl(String interfaceName)
throws NotFoundException {
interfaceNames.add(interfaceName);
thisClass.addInterface(pool.get(interfaceName));
return this;
}
public String field(String code)
throws CannotCompileException {
CtField field;
try {
field = CtField.make(code, thisClass);
} catch (CannotCompileException e) {
logger.error("Unable to compile this code:\n" + code);
throw e;
}
thisClass.addField(field);
return code;
}
public String ctor(String code)
throws CannotCompileException {
CtConstructor constructor;
try {
constructor = CtNewConstructor.make(code, thisClass);
} catch (CannotCompileException e) {
logger.error("Unable to compile this code:\n" + code);
throw e;
}
thisClass.addConstructor(constructor);
return code;
}
public String method(String code)
throws CannotCompileException {
CtMethod m;
try {
m = CtNewMethod.make(code, thisClass);
} catch (CannotCompileException e) {
logger.error("Unable to compile this code:\n" + code);
throw e;
}
thisClass.addMethod(m);
return code;
}
public String asSetter(String field) {
return String.format("set%s%s", Character.toUpperCase(field.charAt(0)), field.substring(1));
}
public String fieldFor(String getterName) {
String sub;
if (getterName.startsWith("is")) {
sub = getterName.substring(2);
} else if (getterName.startsWith("get")) {
sub = getterName.substring(3);
} else {
throw new RuntimeException("Unexpected getter: " + getterName);
}
return sub.substring(0, 1).toLowerCase().concat(sub.substring(1));
}
public Class returnTypeOf(CtMethod method)
throws ClassNotFoundException, NoSuchMethodException {
Method rawMethod = getRawMethod(method);
Pair, Class[]> genericTypePair = getGenericTypePair(rawMethod.getGenericReturnType());
return genericTypePair.getFirst();
}
public Class collectionType(CtMethod method)
throws ClassNotFoundException, NoSuchMethodException {
Method rawMethod = getRawMethod(method);
Pair, Class[]> genericTypePair = getGenericTypePair(rawMethod.getGenericReturnType());
Class[] returnTypeParams = genericTypePair.getSecond();
if (returnTypeParams.length == 0) {
return null;
}
// return either the only (if there is one) or the 2nd (if there are two) type parameters.
return returnTypeParams[returnTypeParams.length - 1];
}
public String wrapperNameFor(Class cls) {
assert cls.isPrimitive() : "Don't call this with a non-primitive type.";
for (Class primitive : PRIMITIVE_WRAPPERS.keySet()) {
if (primitive.getName().equals(cls.getName())) {
return PRIMITIVE_WRAPPERS.get(primitive).getName();
}
}
throw new RuntimeException("No primitive type found for " + cls);
}
public CtClass compile() {
return thisClass;
}
//-------------------------------------------------------------
// Override - Object
//-------------------------------------------------------------
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("class ").append(className);
if (superClassName != null) {
sb.append(" extends ").append(superClassName);
}
if (!interfaceNames.isEmpty()) {
sb.append(" implements ");
for (int i = 0; i < interfaceNames.size(); i++) {
if (i > 0) {
sb.append(", ");
}
sb.append(interfaceNames.get(i));
}
}
return sb.toString();
}
//-------------------------------------------------------------
// Methods - Private
//-------------------------------------------------------------
@SuppressWarnings({"ConstantConditions"})
private Pair, Class[]> getGenericTypePair(Type type) {
if (ParameterizedType.class.isAssignableFrom(type.getClass())) {
Class[] optionalValueTypes = null;
@SuppressWarnings({"ConstantConditions"})
ParameterizedType ptype = (ParameterizedType) type;
if (Map.class.isAssignableFrom((Class) ptype.getRawType())) {
optionalValueTypes = new Class[] { (Class) ptype.getActualTypeArguments()[0],
(Class) ptype.getActualTypeArguments()[1] };
} else if (Iterable.class.isAssignableFrom((Class) ptype.getRawType())) {
optionalValueTypes = new Class[] { (Class) ptype.getActualTypeArguments()[0] };
}
return new Pair, Class[]>((Class) ptype.getRawType(), optionalValueTypes);
} else {
return new Pair, Class[]>((Class) type, new Class[]{});
}
}
private Method getRawMethod(CtMethod method)
throws ClassNotFoundException, NoSuchMethodException {
Class rawClass = Class.forName(method.getDeclaringClass().getName());
return rawClass.getMethod(method.getName());
}
//-------------------------------------------------------------
// Inner Classes
//-------------------------------------------------------------
public class Pair {
//-------------------------------------------------------------
// Variables - Private
//-------------------------------------------------------------
private E first;
private F second;
//-------------------------------------------------------------
// Constructors
//-------------------------------------------------------------
public Pair(E first, F second) {
this.first = first;
this.second = second;
}
//-------------------------------------------------------------
// Methods - Getter/Setter
//-------------------------------------------------------------
public E getFirst() {
return first;
}
public F getSecond() {
return second;
}
}
}
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