Example usage for java.lang Class getConstructors

Introduction

In this page you can find the example usage for java.lang Class getConstructors.

Prototype

@CallerSensitive
public Constructor<?>[] getConstructors() throws SecurityException 

Source Link

Document

Returns an array containing Constructor objects reflecting all the public constructors of the class represented by this Class object.

Usage

From source file:com.oltpbenchmark.util.ClassUtil.java

/**
 * //from w ww  .  j av  a 2s.  co  m
 * @param <T>
 * @param target_class
 * @param params
 * @return
 */
@SuppressWarnings("unchecked")
public static <T> Constructor<T> getConstructor(Class<T> target_class, Class<?>... params) {
    NoSuchMethodException error = null;
    try {
        return (target_class.getConstructor(params));
    } catch (NoSuchMethodException ex) {
        // The first time we get this it can be ignored
        // We'll try to be nice and find a match for them
        error = ex;
    }
    assert (error != null);

    if (LOG.isDebugEnabled()) {
        LOG.debug("TARGET CLASS:  " + target_class);
        LOG.debug("TARGET PARAMS: " + Arrays.toString(params));
    }

    List<Class<?>> paramSuper[] = (List<Class<?>>[]) new List[params.length];
    for (int i = 0; i < params.length; i++) {
        paramSuper[i] = ClassUtil.getSuperClasses(params[i]);
        if (LOG.isDebugEnabled())
            LOG.debug("  SUPER[" + params[i].getSimpleName() + "] => " + paramSuper[i]);
    } // FOR

    for (Constructor<?> c : target_class.getConstructors()) {
        Class<?> cTypes[] = c.getParameterTypes();
        if (LOG.isDebugEnabled()) {
            LOG.debug("CANDIDATE: " + c);
            LOG.debug("CANDIDATE PARAMS: " + Arrays.toString(cTypes));
        }
        if (params.length != cTypes.length)
            continue;

        for (int i = 0; i < params.length; i++) {
            List<Class<?>> cSuper = ClassUtil.getSuperClasses(cTypes[i]);
            if (LOG.isDebugEnabled())
                LOG.debug("  SUPER[" + cTypes[i].getSimpleName() + "] => " + cSuper);
            if (CollectionUtils.intersection(paramSuper[i], cSuper).isEmpty() == false) {
                return ((Constructor<T>) c);
            }
        } // FOR (param)
    } // FOR (constructors)
    throw new RuntimeException("Failed to retrieve constructor for " + target_class.getSimpleName(), error);
}

---

From source file:ch.algotrader.config.ConfigBeanFactory.java

@SuppressWarnings("unchecked")
public <T> T create(final ConfigParams configParams, final Class<T> clazz) {

    Validate.notNull(configParams, "ConfigParams is null");
    Validate.notNull(clazz, "Target class is null");

    Constructor<?>[] constructors = clazz.getConstructors();
    if (constructors.length != 1) {

        throw new ConfigBeanCreationException(
                clazz.getName() + " config bean class is expected to declare one constructor only");
    }//  ww w  .j a v  a  2  s  .c  o  m

    Constructor<?> constructor = constructors[0];
    Annotation[][] parameterAnnotations = constructor.getParameterAnnotations();
    Class<?>[] parameterTypes = constructor.getParameterTypes();
    if (parameterTypes.length != parameterAnnotations.length) {

        throw new ConfigBeanCreationException(clazz.getName() + " config bean metadata is inconsistent");
    }

    Object[] paramValues = new Object[parameterTypes.length];
    for (int i = 0; i < parameterTypes.length; i++) {

        Class<?> paramType = parameterTypes[i];
        Annotation[] annotations = parameterAnnotations[i];
        ConfigName configName = null;
        for (Annotation annotation : annotations) {
            if (annotation.annotationType().equals(ConfigName.class)) {
                configName = (ConfigName) annotation;
                break;
            }
        }
        if (configName == null) {

            throw new ConfigBeanCreationException(
                    clazz.getName() + " config bean parameter does not have mandatory metadata");
        }
        Object paramValue = configParams.getParameter(configName.value(), paramType);
        if (paramValue == null && !configName.optional()) {
            throw new ConfigBeanCreationException("Config parameter '" + configName.value() + "' is undefined");

        }
        paramValues[i] = paramValue;
    }
    try {
        return (T) constructor.newInstance(paramValues);
    } catch (InstantiationException | InvocationTargetException | IllegalAccessException ex) {
        throw new ConfigBeanCreationException(ex);
    }
}

---

From source file:sx.blah.discord.SpoofBot.java

/**
 * Randomly constructs an object./*w w  w. j a  v a  2s.  c  om*/
 *
 * @param client The discord client.
 * @param clazz The class to construct.
 * @param <T> The type of object to construct.
 * @return The constructed object (or null if not possible).
 *
 * @throws IllegalAccessException
 * @throws InvocationTargetException
 * @throws InstantiationException
 */
public static <T> T randomizeObject(IDiscordClient client, Class<T> clazz)
        throws IllegalAccessException, InvocationTargetException, InstantiationException {
    if (canBeRandomized(clazz)) {
        if (String.class.isAssignableFrom(clazz))
            return (T) getRandString();
        else if (Character.class.isAssignableFrom(clazz))
            return (T) getRandCharacter();
        else if (Boolean.class.isAssignableFrom(clazz))
            return (T) getRandBoolean();
        else if (Number.class.isAssignableFrom(clazz))
            return (T) getRandNumber((Class<? extends Number>) clazz);
        else if (Void.class.isAssignableFrom(clazz))
            return null;
        else if (IDiscordClient.class.isAssignableFrom(clazz))
            return (T) client;

    } else {
        outer: for (Constructor constructor : clazz.getConstructors()) {
            Object[] parameters = new Object[constructor.getParameterCount()];
            for (Class<?> param : constructor.getParameterTypes()) {
                if (!canBeRandomized(param))
                    continue outer;
            }
            if (parameters.length > 0) {
                for (int i = 0; i < parameters.length; i++) {
                    parameters[i] = randomizeObject(client, constructor.getParameterTypes()[i]);
                }
                return (T) constructor.newInstance(parameters);
            } else {
                return (T) constructor.newInstance();
            }
        }
    }
    return null;
}

---

From source file:org.jbpm.formModeler.core.model.PojoDataHolder.java

protected Object createInstance(Class pojoClass) throws Exception {
    for (Constructor constructor : pojoClass.getConstructors()) {
        if (constructor.getParameterTypes().length == 0) {
            return constructor.newInstance();
        }//from  ww  w . j a v a2  s .c  o m
    }
    return null;
}

---

From source file:de.xirp.plugin.PluginManager.java

/**
 * Gets an instance of a plugin which is specified by the
 * PluginInfo Object by using a class loader for this plugin.
 * //from w  w  w  . ja v  a  2  s  .  com
 * @param info
 *            Information about the plugin
 * @param robotName
 *            name of the robot this plugin is for
 * @return Instance of the requested plugin
 * @throws Exception
 *             exception when loading the plugin
 */
@SuppressWarnings("unchecked")
protected static SecurePluginView getInstance(PluginInfo info, String robotName) throws Exception {
    // try {
    URLClassLoader classLoader = getClassLoader(info);
    Class<IPlugable> claas = (Class<IPlugable>) Class.forName(info.getMainClass(), true, classLoader);
    Constructor[] constructors = claas.getConstructors();
    Constructor useConstructor = null;
    for (Constructor constructor : constructors) {
        Class[] types = constructor.getParameterTypes();
        if (types.length == 2) {
            // Locale locale = new Locale("");
            if ((types[0] == String.class) && (types[1] == PluginInfo.class)) {
                useConstructor = constructor;
                break;
            }
        } else if (types.length == 2) {
            if ((types[0] == PluginInfo.class)) {
                useConstructor = constructor;
                break;
            }
        }
    }
    if (useConstructor == null) {
        logClass.error(I18n.getString("PluginManager.log.pluginCouldNotBeInstanciatedNoConstructorFound", //$NON-NLS-1$
                info.getMainClass()));
    } else {
        Object[] arglist = new Object[useConstructor.getParameterTypes().length];
        if (arglist.length == 2) {
            arglist[0] = robotName;
            arglist[1] = info;
        } else if (arglist.length == 1) {
            arglist[0] = info;
        }
        IPlugable plugin = (IPlugable) useConstructor.newInstance(arglist);
        return new SecurePluginView(plugin);
    }
    return null;
}

---

From source file:org.jsonschema2pojo.integration.config.UseInnerClassBuildersIT.java

/**
 * This method confirms that by default the only constructor available to a builder is the empty argument constructor
 *//*from w ww. java2s .  c  om*/
@Test
public void innerBuilderExtraConstructorsRequireConfig() throws ClassNotFoundException {
    ClassLoader resultsClassLoader = schemaRule.generateAndCompile("/schema.useInnerClassBuilders/child.json",
            "com.example", config("generateBuilders", true, "useInnerClassBuilders", true));

    Class<?> builderClass = resultsClassLoader.loadClass("com.example.Child$ChildBuilder");
    assertEquals(1, builderClass.getConstructors().length);

    Constructor<?> constructor = builderClass.getConstructors()[0];
    assertEquals(0, constructor.getParameterCount());
}

---

From source file:jetbrains.buildServer.server.rest.util.BeanFactory.java

@Nullable
private <T> Constructor<T> findConstructor(@NotNull final Class<T> clazz, Class<?>[] argTypes) {
    try {/*from  ww w .j a  va 2  s  . co  m*/
        return clazz.getConstructor(argTypes);
    } catch (NoSuchMethodException e) {
        //NOP
    }

    for (Constructor c : clazz.getConstructors()) {
        final Class[] reqTypes = c.getParameterTypes();
        if (checkParametersMatch(argTypes, reqTypes)) {
            //noinspection unchecked
            return (Constructor<T>) c;
        }
    }
    return null;
}

---

From source file:fitnesse.slim.StatementExecutor.java

private Object createInstanceOfConstructor(String className, Object[] args) throws IllegalArgumentException,
        InstantiationException, IllegalAccessException, InvocationTargetException {
    Class<?> k = searchPathsForClass(className);
    Constructor<?> constructor = getConstructor(k.getConstructors(), args);
    if (constructor == null)
        throw new SlimError(String.format("message:<<NO_CONSTRUCTOR %s>>", className));

    Object newInstance = newInstance(args, constructor);
    if (newInstance instanceof StatementExecutorConsumer) {
        ((StatementExecutorConsumer) newInstance).setStatementExecutor(this);
    }/*from  ww w.j  a va  2s  . c o  m*/
    return newInstance;

}

---

From source file:org.jdto.impl.AnnotationBeanInspector.java

@Override
Constructor findAppropiateConstructor(Class beanClass) {
    Constructor[] beanConstructors = beanClass.getConstructors();

    for (Constructor constructor : beanConstructors) {
        if (constructor.isAnnotationPresent(DTOConstructor.class)) {
            return constructor;
        }/*from  w w w  . java2 s  .  co m*/
    }

    if (beanConstructors != null && beanConstructors.length > 0) {
        //return the last constructor.
        return beanConstructors[beanConstructors.length - 1];
    } else {
        return null;
    }

}

---

From source file:com.cloudera.livy.client.common.TestHttpMessages.java

/**
 * Tests that all defined messages can be serialized and deserialized using Jackson.
 *//*from  ww  w  .ja  v  a  2 s  . c  om*/
@Test
public void testMessageSerialization() throws Exception {
    ObjectMapper mapper = new ObjectMapper();

    for (Class<?> msg : HttpMessages.class.getClasses()) {
        if (msg.isInterface()) {
            continue;
        }

        String name = msg.getSimpleName();

        Constructor c = msg.getConstructors()[0];
        Object[] params = new Object[c.getParameterTypes().length];
        Type[] genericTypes = c.getGenericParameterTypes();
        for (int i = 0; i < params.length; i++) {
            params[i] = dummyValue(c.getParameterTypes()[i], genericTypes[i]);
        }

        Object o1 = c.newInstance(params);
        byte[] serialized = mapper.writeValueAsBytes(o1);
        Object o2 = mapper.readValue(serialized, msg);

        assertNotNull("could not deserialize " + name, o2);
        for (Field f : msg.getFields()) {
            checkEquals(name, f, o1, o2);
        }
    }

}

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