package com.jsoniter;

import java.lang.reflect.ParameterizedType;

import java.lang.reflect.Type;

public class TypeLiteral<T> {

final Type type;

final String cacheKey;

/**

* Constructs a new type literal. Derives represented class from type parameter.

* <p>

* <p>Clients create an empty anonymous subclass. Doing so embeds the type parameter in the

* anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.

*/

@SuppressWarnings("unchecked")

protected TypeLiteral() {

this.type = getSuperclassTypeParameter(getClass());

cacheKey = generateCacheKey(type);

}

public static String generateCacheKey(Type type) {

StringBuilder decoderClassName = new StringBuilder("codegen.");

if (type instanceof Class) {

Class clazz = (Class) type;

decoderClassName.append(clazz.getName().replace("[", "array_"));

} else if (type instanceof ParameterizedType) {

ParameterizedType pType = (ParameterizedType) type;

Class clazz = (Class) pType.getRawType();

decoderClassName.append(clazz.getName().replace("[", "array_"));

for (int i = 0; i < pType.getActualTypeArguments().length; i++) {

Class typeArg = (Class) pType.getActualTypeArguments()[i];

decoderClassName.append('_');

decoderClassName.append(typeArg.getName());

}

} else {

throw new UnsupportedOperationException("do not know how to handle: " + type);

}

return decoderClassName.toString().replace("$", "_");

}

static Type getSuperclassTypeParameter(Class<?> subclass) {

Type superclass = subclass.getGenericSuperclass();

if (superclass instanceof Class) {

throw new RuntimeException("Missing type parameter.");

}

ParameterizedType parameterized = (ParameterizedType) superclass;

return parameterized.getActualTypeArguments()[0];

}

public Type getType() {

return type;

}

public String getCacheKey() {

return cacheKey;

}

}