List of usage examples for org.springframework.beans BeanUtils findPrimaryConstructor
@SuppressWarnings("unchecked") @Nullable public static <T> Constructor<T> findPrimaryConstructor(Class<T> clazz)
From source file:org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.java
@Override @Nullable//from w w w . java 2 s .c om public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, final String beanName) throws BeanCreationException { // Let's check for lookup methods here.. if (!this.lookupMethodsChecked.contains(beanName)) { try { ReflectionUtils.doWithMethods(beanClass, method -> { Lookup lookup = method.getAnnotation(Lookup.class); if (lookup != null) { Assert.state(beanFactory != null, "No BeanFactory available"); LookupOverride override = new LookupOverride(method, lookup.value()); try { RootBeanDefinition mbd = (RootBeanDefinition) beanFactory .getMergedBeanDefinition(beanName); mbd.getMethodOverrides().addOverride(override); } catch (NoSuchBeanDefinitionException ex) { throw new BeanCreationException(beanName, "Cannot apply @Lookup to beans without corresponding bean definition"); } } }); } catch (IllegalStateException ex) { throw new BeanCreationException(beanName, "Lookup method resolution failed", ex); } this.lookupMethodsChecked.add(beanName); } // Quick check on the concurrent map first, with minimal locking. Constructor<?>[] candidateConstructors = this.candidateConstructorsCache.get(beanClass); if (candidateConstructors == null) { // Fully synchronized resolution now... synchronized (this.candidateConstructorsCache) { candidateConstructors = this.candidateConstructorsCache.get(beanClass); if (candidateConstructors == null) { Constructor<?>[] rawCandidates; try { rawCandidates = beanClass.getDeclaredConstructors(); } catch (Throwable ex) { throw new BeanCreationException(beanName, "Resolution of declared constructors on bean Class [" + beanClass.getName() + "] from ClassLoader [" + beanClass.getClassLoader() + "] failed", ex); } List<Constructor<?>> candidates = new ArrayList<>(rawCandidates.length); Constructor<?> requiredConstructor = null; Constructor<?> defaultConstructor = null; Constructor<?> primaryConstructor = BeanUtils.findPrimaryConstructor(beanClass); int nonSyntheticConstructors = 0; for (Constructor<?> candidate : rawCandidates) { if (!candidate.isSynthetic()) { nonSyntheticConstructors++; } else if (primaryConstructor != null) { continue; } AnnotationAttributes ann = findAutowiredAnnotation(candidate); if (ann == null) { Class<?> userClass = ClassUtils.getUserClass(beanClass); if (userClass != beanClass) { try { Constructor<?> superCtor = userClass .getDeclaredConstructor(candidate.getParameterTypes()); ann = findAutowiredAnnotation(superCtor); } catch (NoSuchMethodException ex) { // Simply proceed, no equivalent superclass constructor found... } } } if (ann != null) { if (requiredConstructor != null) { throw new BeanCreationException(beanName, "Invalid autowire-marked constructor: " + candidate + ". Found constructor with 'required' Autowired annotation already: " + requiredConstructor); } boolean required = determineRequiredStatus(ann); if (required) { if (!candidates.isEmpty()) { throw new BeanCreationException(beanName, "Invalid autowire-marked constructors: " + candidates + ". Found constructor with 'required' Autowired annotation: " + candidate); } requiredConstructor = candidate; } candidates.add(candidate); } else if (candidate.getParameterCount() == 0) { defaultConstructor = candidate; } } if (!candidates.isEmpty()) { // Add default constructor to list of optional constructors, as fallback. if (requiredConstructor == null) { if (defaultConstructor != null) { candidates.add(defaultConstructor); } else if (candidates.size() == 1 && logger.isWarnEnabled()) { logger.warn("Inconsistent constructor declaration on bean with name '" + beanName + "': single autowire-marked constructor flagged as optional - " + "this constructor is effectively required since there is no " + "default constructor to fall back to: " + candidates.get(0)); } } candidateConstructors = candidates.toArray(new Constructor<?>[candidates.size()]); } else if (rawCandidates.length == 1 && rawCandidates[0].getParameterCount() > 0) { candidateConstructors = new Constructor<?>[] { rawCandidates[0] }; } else if (nonSyntheticConstructors == 2 && primaryConstructor != null && defaultConstructor != null && !primaryConstructor.equals(defaultConstructor)) { candidateConstructors = new Constructor<?>[] { primaryConstructor, defaultConstructor }; } else if (nonSyntheticConstructors == 1 && primaryConstructor != null) { candidateConstructors = new Constructor<?>[] { primaryConstructor }; } else { candidateConstructors = new Constructor<?>[0]; } this.candidateConstructorsCache.put(beanClass, candidateConstructors); } } } return (candidateConstructors.length > 0 ? candidateConstructors : null); }
From source file:org.springframework.web.method.annotation.ModelAttributeMethodProcessor.java
/** * Extension point to create the model attribute if not found in the model, * with subsequent parameter binding through bean properties (unless suppressed). * <p>The default implementation typically uses the unique public no-arg constructor * if available but also handles a "primary constructor" approach for data classes: * It understands the JavaBeans {@link ConstructorProperties} annotation as well as * runtime-retained parameter names in the bytecode, associating request parameters * with constructor arguments by name. If no such constructor is found, the default * constructor will be used (even if not public), assuming subsequent bean property * bindings through setter methods./* w w w.j av a2 s . c om*/ * @param attributeName the name of the attribute (never {@code null}) * @param parameter the method parameter declaration * @param binderFactory for creating WebDataBinder instance * @param webRequest the current request * @return the created model attribute (never {@code null}) * @throws BindException in case of constructor argument binding failure * @throws Exception in case of constructor invocation failure * @see #constructAttribute(Constructor, String, WebDataBinderFactory, NativeWebRequest) * @see BeanUtils#findPrimaryConstructor(Class) */ protected Object createAttribute(String attributeName, MethodParameter parameter, WebDataBinderFactory binderFactory, NativeWebRequest webRequest) throws Exception { MethodParameter nestedParameter = parameter.nestedIfOptional(); Class<?> clazz = nestedParameter.getNestedParameterType(); Constructor<?> ctor = BeanUtils.findPrimaryConstructor(clazz); if (ctor == null) { Constructor<?>[] ctors = clazz.getConstructors(); if (ctors.length == 1) { ctor = ctors[0]; } else { try { ctor = clazz.getDeclaredConstructor(); } catch (NoSuchMethodException ex) { throw new IllegalStateException("No primary or default constructor found for " + clazz, ex); } } } Object attribute = constructAttribute(ctor, attributeName, binderFactory, webRequest); if (parameter != nestedParameter) { attribute = Optional.of(attribute); } return attribute; }