org.springframework.util.ClassUtils#getConstructorIfAvailable ( )源码实例Demo

/**
 * Attempt to create a copy of the supplied {@code TestContext} using its
 * <em>copy constructor</em>.
 */
private static TestContext copyTestContext(TestContext testContext) {
	Constructor<? extends TestContext> constructor =
			ClassUtils.getConstructorIfAvailable(testContext.getClass(), testContext.getClass());

	if (constructor != null) {
		try {
			ReflectionUtils.makeAccessible(constructor);
			return constructor.newInstance(testContext);
		}
		catch (Exception ex) {
			if (logger.isInfoEnabled()) {
				logger.info(String.format("Failed to invoke copy constructor for [%s]; " +
						"concurrent test execution is therefore likely not supported.",
						testContext), ex);
			}
		}
	}

	// Fallback to original instance
	return testContext;
}
 

/**
 * Attempt to create a copy of the supplied {@code TestContext} using its
 * <em>copy constructor</em>.
 */
private static TestContext copyTestContext(TestContext testContext) {
	Constructor<? extends TestContext> constructor =
			ClassUtils.getConstructorIfAvailable(testContext.getClass(), testContext.getClass());

	if (constructor != null) {
		try {
			ReflectionUtils.makeAccessible(constructor);
			return constructor.newInstance(testContext);
		}
		catch (Exception ex) {
			if (logger.isInfoEnabled()) {
				logger.info(String.format("Failed to invoke copy constructor for [%s]; " +
						"concurrent test execution is therefore likely not supported.",
						testContext), ex);
			}
		}
	}

	// Fallback to original instance
	return testContext;
}
 

private static SolrClient cloneCloudSolrClient(SolrClient solrClient, String core) {
	if (VersionUtil.isSolr3XAvailable() || solrClient == null) {
		return null;
	}

	CloudSolrClient cloudServer = (CloudSolrClient) solrClient;
	String zkHost = readField(solrClient, "zkHost");

	Constructor<? extends SolrClient> constructor = (Constructor<? extends SolrClient>) ClassUtils
			.getConstructorIfAvailable(solrClient.getClass(), String.class, LBHttpSolrClient.class);

	CloudSolrClient clone = (CloudSolrClient) BeanUtils.instantiateClass(constructor, zkHost,
			cloneLBHttpSolrClient(cloudServer.getLbClient(), core));

	if (org.springframework.util.StringUtils.hasText(core)) {
		clone.setDefaultCollection(core);
	}
	return clone;
}
 

private static HttpClient cloneHttpClient(HttpClient sourceClient)
		throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {

	if (sourceClient == null) {
		return null;
	}

	Class<?> clientType = ClassUtils.getUserClass(sourceClient);
	Constructor<?> constructor = ClassUtils.getConstructorIfAvailable(clientType, HttpParams.class);
	if (constructor != null) {

		HttpClient targetClient = (HttpClient) constructor.newInstance(sourceClient.getParams());
		BeanUtils.copyProperties(sourceClient, targetClient);
		return targetClient;
	} else {
		return new DefaultHttpClient(sourceClient.getParams());
	}

}
 

@Override
public Object clone(Object entity) {

    Class clazz = entity.getClass();
    Constructor copyCtor = ClassUtils.getConstructorIfAvailable(clazz, clazz);
    if (copyCtor == null) {
        throw new LockingAndVersioningException(format("no copy constructor: %s", clazz.getCanonicalName()));
    }

    Object newInstance = null;
    try {
        newInstance = copyCtor.newInstance(entity);
    } catch (Exception e) {
        throw new LockingAndVersioningException("copy constructor failed", e);
    }
    return newInstance;
}
 

@Override
public MimeMessage createMimeMessage() {

	// We have to use reflection as SmartMimeMessage is not package-private
	if (ClassUtils.isPresent(SMART_MIME_MESSAGE_CLASS_NAME,
			ClassUtils.getDefaultClassLoader())) {
		Class<?> smartMimeMessage = ClassUtils.resolveClassName(
				SMART_MIME_MESSAGE_CLASS_NAME, ClassUtils.getDefaultClassLoader());
		Constructor<?> constructor = ClassUtils.getConstructorIfAvailable(
				smartMimeMessage, Session.class, String.class, FileTypeMap.class);
		if (constructor != null) {
			Object mimeMessage = BeanUtils.instantiateClass(constructor, getSession(),
					this.defaultEncoding, this.defaultFileTypeMap);
			return (MimeMessage) mimeMessage;
		}
	}

	return new MimeMessage(getSession());
}
 

@Override
@SuppressWarnings("unchecked")
public RepositoryQuery resolveQuery(Method method, RepositoryMetadata metadata, ProjectionFactory factory,
		NamedQueries namedQueries) {

	QueryMethod queryMethod = new QueryMethod(method, metadata, factory);

	Constructor<? extends KeyValuePartTreeQuery> constructor = (Constructor<? extends KeyValuePartTreeQuery>) ClassUtils
			.getConstructorIfAvailable(this.repositoryQueryType, QueryMethod.class,
					QueryMethodEvaluationContextProvider.class, KeyValueOperations.class, Class.class);

	Assert.state(constructor != null,
			String.format(
					"Constructor %s(QueryMethod, EvaluationContextProvider, KeyValueOperations, Class) not available!",
					ClassUtils.getShortName(this.repositoryQueryType)));

	return BeanUtils.instantiateClass(constructor, queryMethod, evaluationContextProvider, this.keyValueOperations,
			this.queryCreator);
}
 

/**
 * Creates a request control using the constructor parameters given in
 * <code>params</code>.
 * @param paramTypes Types of the constructor parameters
 * @param params Actual constructor parameters
 * @return Control to be used by the DirContextProcessor
 */
public Control createRequestControl(Class<?>[] paramTypes, Object[] params) {
	Constructor<?> constructor = ClassUtils.getConstructorIfAvailable(requestControlClass, paramTypes);
	if (constructor == null) {
		throw new IllegalArgumentException("Failed to find an appropriate RequestControl constructor");
	}

	Control result = null;
	try {
		result = (Control) constructor.newInstance(params);
	}
	catch (Exception e) {
		ReflectionUtils.handleReflectionException(e);
	}

	return result;
}
 

public Control createRequestControl() {
	byte[] actualCookie = null;
	if (cookie != null) {
		actualCookie = cookie.getCookie();
	}
	Constructor constructor = ClassUtils.getConstructorIfAvailable(requestControlClass, new Class[] { int.class,
			byte[].class, boolean.class });
	if (constructor == null) {
		throw new IllegalArgumentException("Failed to find an appropriate RequestControl constructor");
	}

	Control result = null;
	try {
		result = (Control) constructor.newInstance(pageSize, actualCookie,
                   critical);
	}
	catch (Exception e) {
		ReflectionUtils.handleReflectionException(e);
	}

	return result;
}
 

@SuppressWarnings({ "unchecked", "rawtypes" })
private static SolrClient cloneEmbeddedSolrServer(SolrClient solrClient, String core) {

	CoreContainer coreContainer = ((EmbeddedSolrServer) solrClient).getCoreContainer();
	try {
		Constructor constructor = ClassUtils.getConstructorIfAvailable(solrClient.getClass(), CoreContainer.class,
				String.class);
		return (SolrClient) BeanUtils.instantiateClass(constructor, coreContainer, core);
	} catch (Exception e) {
		throw new BeanInstantiationException(solrClient.getClass(),
				"Cannot create instace of " + solrClient.getClass() + ".", e);
	}
}
 

private Constructor<?> getCustomCtor(Class<?> type) {
    for (Constructor<?> ctor : type.getDeclaredConstructors()) {
        if (ctor.isAnnotationPresent(DynamicComponent.class) && !isJsonConstructor(ctor)) {
            return ctor;
        }
    }
    return ClassUtils.getConstructorIfAvailable(type);
}
 

/**
 * Create the BeanContainer to use.
 * @param beanClass bean type in container
 * @param data intial data.
 * @return a new BeanContainer
 */
protected Container createBeanContainer(Class<T> beanClass, List<T> data) {
	Constructor<?extends Container> ctor = 
			ClassUtils.getConstructorIfAvailable(this.containerClass, Class.class, Collection.class);
	
	if (ctor != null)
		return BeanUtils.instantiateClass(ctor, beanClass, data);
	
	return new BeanItemContainer<T>(beanClass, data);
}
 

@Nullable
private static Constructor<?> determineFactoryConstructor(Class<?> targetClass, Class<?> sourceClass) {
	return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
}
 

@Nullable
private static Constructor<?> determineFactoryConstructor(Class<?> targetClass, Class<?> sourceClass) {
	return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
}
 

private static Constructor<?> determineFactoryConstructor(Class<?> targetClass, Class<?> sourceClass) {
	return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
}
 

private static Constructor<?> determineFactoryConstructor(Class<?> targetClass, Class<?> sourceClass) {
	return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
}
 

public DashboardExtensionsPanel(
        final String id, final List<Class<? extends BaseExtWidget>> extWidgetClasses, final PageReference pageRef) {

    super(id);

    List<BaseExtWidget> instances = new ArrayList<>();

    for (final Class<? extends BaseExtWidget> clazz : extWidgetClasses) {
        final Constructor<? extends BaseExtWidget> constructor =
                ClassUtils.getConstructorIfAvailable(clazz, String.class, PageReference.class);
        if (constructor == null) {
            LOG.error("Could not find required construtor in {}, ignoring", clazz);
        } else {
            try {
                instances.add(constructor.newInstance("widget", pageRef));
            } catch (Exception e) {
                LOG.error("While creating instance of {}", clazz, e);
            }
        }
    }

    ListView<BaseExtWidget> widgets = new ListView<BaseExtWidget>("widgets", instances) {

        private static final long serialVersionUID = 4949588177564901031L;

        @Override
        protected void populateItem(final ListItem<BaseExtWidget> item) {
            WebMarkupContainer widgetContainer = new WebMarkupContainer("widgetContainer");
            widgetContainer.setOutputMarkupId(true);
            ExtWidget ann = item.getModelObject().getClass().getAnnotation(ExtWidget.class);
            if (ann != null) {
                widgetContainer.add(new AttributeModifier("class", ann.cssClass()));
            }
            item.add(widgetContainer);

            item.getModelObject().setOutputMarkupId(true);
            widgetContainer.add(item.getModelObject());
        }
    };
    add(widgets);
}
 

ConstructorCachingQueryCreatorFactory(Class<? extends AbstractQueryCreator<?, ?>> type) {

			this.type = type;
			this.constructor = ClassUtils.getConstructorIfAvailable(type, PartTree.class, ParameterAccessor.class);
		}
 

/**
 * Create {@link org.apache.solr.core.CoreContainer} via its constructor
 * (Solr 3.6.0 - 4.3.1)
 *
 * @param solrHomeDirectory
 * @param solrXmlFile
 * @return
 */
private CoreContainer createCoreContainerViaConstructor(String solrHomeDirectory, File solrXmlFile) {
	Constructor<CoreContainer> constructor = ClassUtils.getConstructorIfAvailable(CoreContainer.class, String.class,
			File.class);
	return BeanUtils.instantiateClass(constructor, solrHomeDirectory, solrXmlFile);
}