org.apache.cayenne.di.spi.FieldInjectingProvider Maven / Gradle / Ivy
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package org.apache.cayenne.di.spi;
import java.lang.reflect.Field;
import org.apache.cayenne.ConfigurationException;
import org.apache.cayenne.di.Inject;
import org.apache.cayenne.di.Key;
import org.apache.cayenne.di.Provider;
/**
* @since 3.1
*/
class FieldInjectingProvider implements Provider {
private DefaultInjector injector;
private Provider delegate;
FieldInjectingProvider(Provider delegate, DefaultInjector injector) {
this.delegate = delegate;
this.injector = injector;
}
public T get() throws ConfigurationException {
T object = delegate.get();
injectMembers(object, object.getClass());
return object;
}
private void injectMembers(T object, Class type) {
// bail on recursion stop condition
if (type == null) {
return;
}
for (Field field : type.getDeclaredFields()) {
Inject inject = field.getAnnotation(Inject.class);
if (inject != null) {
injectMember(object, field, inject.value());
}
}
injectMembers(object, type.getSuperclass());
}
private void injectMember(Object object, Field field, String bindingName) {
InjectionStack stack = injector.getInjectionStack();
Object value;
Class fieldType = field.getType();
if (Provider.class.equals(fieldType)) {
Class objectClass = DIUtil.parameterClass(field.getGenericType());
if (objectClass == null) {
throw new ConfigurationException(
"Provider field %s.%s of type %s must be "
+ "parameterized to be usable for injection",
field.getDeclaringClass().getName(),
field.getName(),
fieldType.getName());
}
value = injector.getProvider(Key.get(objectClass, bindingName));
}
else {
Key key = Key.get(fieldType, bindingName);
stack.push(key);
try {
value = injector.getInstance(key);
}
finally {
stack.pop();
}
}
field.setAccessible(true);
try {
field.set(object, value);
}
catch (Exception e) {
String message = String.format(
"Error injecting into field %s.%s of type %s",
field.getDeclaringClass().getName(),
field.getName(),
fieldType.getName());
throw new ConfigurationException(message, e);
}
}
}