GwtDotCreateProviderPatcher.java

package com.googlecode.gwt.test.internal.patchers;

import com.google.gwt.core.client.GWT;
import com.google.gwt.inject.rebind.adapter.GwtDotCreateProvider;
import com.google.inject.Binding;
import com.google.inject.Inject;
import com.google.inject.binder.LinkedBindingBuilder;
import com.google.inject.binder.ScopedBindingBuilder;
import com.google.inject.internal.AbstractBindingBuilder;
import com.googlecode.gwt.test.gin.GwtTestGinException;
import com.googlecode.gwt.test.patchers.InitMethod;
import com.googlecode.gwt.test.patchers.PatchClass;
import com.googlecode.gwt.test.patchers.PatchMethod;
import com.googlecode.gwt.test.utils.GwtReflectionUtils;
import javassist.CannotCompileException;
import javassist.CtClass;
import javassist.CtField;

import java.lang.reflect.Constructor;
import java.lang.reflect.Type;

@SuppressWarnings("unchecked")
@PatchClass(target = "com.google.gwt.inject.rebind.adapter.GwtDotCreateProvider")
class GwtDotCreateProviderPatcher {

    private static final String BINDED_CLASS_FIELD = "gwtTestUtilsBindedClass";

    @PatchMethod
    static <T> ScopedBindingBuilder bind(LinkedBindingBuilder<T> builder) {

        if (!(builder instanceof AbstractBindingBuilder)) {
            throw new GwtTestGinException("Not managed " + LinkedBindingBuilder.class.getSimpleName()
                    + " implementation : " + builder.getClass().getName());
        }

        Binding<T> binding = GwtReflectionUtils.<Binding<T>>getPrivateFieldValue(builder, "binding");

        Type type = binding.getKey().getTypeLiteral().getType();

        if (!(type instanceof Class)) {
            throw new GwtTestGinException("Not managed binded type : " + type);
        }

        Constructor<T> atInjectConstructor = getAtInjectConstructor((Class<T>) type);
        if (atInjectConstructor != null) {
            return builder.toConstructor(atInjectConstructor);
        }

        GwtDotCreateProvider<T> gwtDotCreateProvider = GwtReflectionUtils.instantiateClass(GwtDotCreateProvider.class);

        GwtReflectionUtils.setPrivateFieldValue(gwtDotCreateProvider, BINDED_CLASS_FIELD, type);

        return builder.toProvider(gwtDotCreateProvider);
    }

    @PatchMethod
    static <T> T get(GwtDotCreateProvider<?> gwtDotCreateProvider) {
        Class<T> bindedType = GwtReflectionUtils.<Class<T>>getPrivateFieldValue(
                gwtDotCreateProvider, BINDED_CLASS_FIELD);

        return GWT.<T>create(bindedType);
    }

    @InitMethod
    static void initClass(CtClass ctClass) throws CannotCompileException {
        CtField field = CtField.make("private Class " + BINDED_CLASS_FIELD + ";", ctClass);
        ctClass.addField(field);
    }

    private static <T> Constructor<T> getAtInjectConstructor(Class<T> toInstanciate) {
        for (Constructor<?> cons : toInstanciate.getDeclaredConstructors()) {
            if (cons.getAnnotation(Inject.class) != null) {
                return (Constructor<T>) cons;
            }
        }
        return null;
    }

}