Example usage for java.lang.reflect Constructor newInstance

Introduction

In this page you can find the example usage for java.lang.reflect Constructor newInstance.

Prototype

@CallerSensitive
@ForceInline 
public T newInstance(Object... initargs) throws InstantiationException, IllegalAccessException,
        IllegalArgumentException, InvocationTargetException 

Source Link

Document

Uses the constructor represented by this Constructor object to create and initialize a new instance of the constructor's declaring class, with the specified initialization parameters.

Usage

From source file:TimeLib.java

/**
 * Get a new Date instance of the specified subclass and given long value.
 * @param type the concrete subclass of the Date instance, must be an
 * instance of subclass of java.util.Date
 * @param d the date/time value as a long
 * @return the new Date instance, or null if the class type is not valid
 *///w w  w .java 2 s .c  om
public static Date getDate(Class type, long d) {
    try {
        Constructor c = type.getConstructor(new Class[] { long.class });
        return (Date) c.newInstance(new Object[] { new Long(d) });
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}

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From source file:info.novatec.testit.livingdoc.util.ClassUtils.java

public static <C> C createInstanceFromClassNameWithArguments(ClassLoader classLoader, String classWithArguments,
        Class<C> expectedType) throws UndeclaredThrowableException {
    try {//  w w  w.  j a  v a2s .c  o  m
        List<String> parameters = toList(escapeValues(classWithArguments.split(";")));
        Class<?> klass = ClassUtils.loadClass(classLoader, shift(parameters));

        if (!expectedType.isAssignableFrom(klass)) {
            throw new IllegalArgumentException(
                    "Class " + expectedType.getName() + " is not assignable from " + klass.getName());
        }

        if (parameters.size() == 0) {
            return expectedType.cast(klass.newInstance());
        }

        String[] args = parameters.toArray(new String[parameters.size()]);
        Constructor<?> constructor = klass.getConstructor(args.getClass());
        return expectedType.cast(constructor.newInstance(new Object[] { args }));
    } catch (ClassNotFoundException e) {
        throw new UndeclaredThrowableException(e);
    } catch (InstantiationException e) {
        throw new UndeclaredThrowableException(e);
    } catch (IllegalAccessException e) {
        throw new UndeclaredThrowableException(e);
    } catch (NoSuchMethodException e) {
        throw new UndeclaredThrowableException(e);
    } catch (InvocationTargetException e) {
        throw new UndeclaredThrowableException(e);
    }
}

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From source file:eu.esdihumboldt.hale.io.geoserver.ResourceBuilder.java

public static <T extends DataStore> ResourceBuilder dataStore(String name, Class<T> dataStoreType) {
    if (dataStoreType == null) {
        throw new IllegalArgumentException("DataStore type not specified");
    }/*from   w w w. jav  a 2 s.c om*/

    Constructor<T> constructor;
    try {
        // TODO: this code assumes a constructor taking a single String
        // parameter exists
        constructor = dataStoreType.getConstructor(String.class);

        return new ResourceBuilder(constructor.newInstance(name));
    } catch (Exception e) {
        throw new RuntimeException("Cannot instantiate DataStore type: " + dataStoreType.getName());
    }
}

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From source file:org.jamwiki.utils.ResourceUtil.java

/**
 * Given a String representation of a class name (for example, org.jamwiki.db.AnsiDataHandler)
 * return an instance of the class.  The constructor for the class being instantiated must
 * not take any arguments.// w  ww  .j  a va  2 s.com
 *
 * @param className The name of the class being instantiated.
 * @return A Java Object representing an instance of the specified class.
 */
public static Object instantiateClass(String className) {
    if (StringUtils.isBlank(className)) {
        throw new IllegalArgumentException("Cannot call instantiateClass with an empty class name");
    }
    if (logger.isDebugEnabled()) {
        logger.debug("Instantiating class: " + className);
    }
    try {
        Class clazz = ClassUtils.forName(className, ClassUtils.getDefaultClassLoader());
        Class[] parameterTypes = new Class[0];
        Constructor constructor = clazz.getConstructor(parameterTypes);
        Object[] initArgs = new Object[0];
        return constructor.newInstance(initArgs);
    } catch (ClassNotFoundException e) {
        throw new IllegalStateException("Invalid class name specified: " + className, e);
    } catch (NoSuchMethodException e) {
        throw new IllegalStateException("Specified class does not have a valid constructor: " + className, e);
    } catch (IllegalAccessException e) {
        throw new IllegalStateException("Specified class does not have a valid constructor: " + className, e);
    } catch (InvocationTargetException e) {
        throw new IllegalStateException("Specified class does not have a valid constructor: " + className, e);
    } catch (InstantiationException e) {
        throw new IllegalStateException("Specified class could not be instantiated: " + className, e);
    }
}

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From source file:fr.opensagres.xdocreport.core.logging.LogUtils.java

/**
 * Create a logger/*w w w.j  av a  2  s . c om*/
 */
protected static Logger createLogger(String loggerName) {
    if (loggerClass != null) {

        try {

            Constructor<? extends AbstractDelegatingLogger> cns = loggerClass.getConstructor(String.class);
            return cns.newInstance(loggerName);

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    return Logger.getLogger(loggerName, null);

}

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From source file:edu.cwru.sepia.Main.java

private static Agent[] getAgents(HierarchicalConfiguration config) {
    String[] participatingAgents = config.getStringArray("agents.ParticipatingAgents");
    Agent[] agents = new Agent[participatingAgents.length];

    for (int i = 0; i < participatingAgents.length; i++) {
        String key = "agents." + participatingAgents[i];
        HierarchicalConfiguration agentConfig = config.configurationAt(key);
        String className = agentConfig.getString("ClassName");
        int playerId = agentConfig.getInt("PlayerId");
        String[] arguments = agentConfig.getStringArray("ConstructorArguments");
        try {//from  w w w .  java2s  . co m
            Class<?> classDef = Class.forName(className);
            Agent agent = null;
            try {
                if (arguments != null && arguments.length != 0)
                    agent = (Agent) classDef.getConstructor(int.class, String[].class).newInstance(playerId,
                            arguments);
            } catch (Exception e) {
            }
            if (agent == null) {
                @SuppressWarnings("unchecked")
                Constructor<? extends Agent> constructor = (Constructor<? extends Agent>) classDef
                        .getConstructor(int.class);
                agent = (Agent) constructor.newInstance(playerId);
            }
            agents[i] = agent;
        } catch (Exception ex) {
            String errorMessage = String.format("Unable to instantiate %s with playerId %d%s.", className,
                    playerId,
                    (arguments == null ? "" : " and additional arguments " + Arrays.toString(arguments)));
            logger.log(Level.SEVERE, errorMessage, ex);
            throw new RuntimeException(ex);//make sure the program fails and the error gets propagated
        }
        agents[i].setConfiguration(agentConfig);
    }

    return agents;
}

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From source file:net.big_oh.common.web.filters.ipaddress.IPAddressFilter.java

private static IPAddressFilterRule instantiateIPAddressFilterRule(String className, String constructorParam) {

    IPAddressFilterRule newIPAddressFilterRule = null;

    try {/*from   w w w . j ava  2  s.  co  m*/
        // Get the class declared in the FilterConfig parameter.
        Class<?> filterRuleClass = Class.forName(className);

        // Try to instantiate an instance of the IPAddressFilterRule class
        // Look for an appropriate constructor that takes a single
        // java.lang.String
        Constructor<?> constructor = filterRuleClass.getConstructor(String.class);

        newIPAddressFilterRule = (IPAddressFilterRule) constructor.newInstance(constructorParam);
    } catch (ClassNotFoundException cnfe) {
        logger.error("Could not find a class named " + className);
    } catch (NoSuchMethodException e) {
        logger.error("Could not instantiate an instance of class " + className + ".");
        logger.error(e);
    } catch (InstantiationException e) {
        logger.error("Could not instantiate an instance of class " + className + ".");
        logger.error(e);
    } catch (IllegalAccessException e) {
        logger.error("Could not instantiate an instance of class " + className + ".");
        logger.error(e);
    } catch (InvocationTargetException e) {
        logger.error("Could not instantiate an instance of class " + className + ".");
        logger.error(e);
    } catch (RuntimeException e) {
        logger.error("Could not instantiate an instance of class " + className + ".");
        logger.error(e);
    }

    return newIPAddressFilterRule;

}

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From source file:eu.stratosphere.nephele.profiling.ProfilingUtils.java

/**
 * Creates an instance of the job manager's profiling component.
 * /* w ww. j ava  2  s .c  om*/
 * @param profilerClassName
 *        the class name of the profiling component to load
 * @param jobManagerBindAddress
 *        the address the job manager's RPC server is bound to
 * @return an instance of the job manager profiling component or <code>null</code> if an error occurs
 */
@SuppressWarnings("unchecked")
public static JobManagerProfiler loadJobManagerProfiler(String profilerClassName,
        InetAddress jobManagerBindAddress) {

    final Class<? extends JobManagerProfiler> profilerClass;
    try {
        profilerClass = (Class<? extends JobManagerProfiler>) Class.forName(profilerClassName);
    } catch (ClassNotFoundException e) {
        LOG.error("Cannot find class " + profilerClassName + ": " + StringUtils.stringifyException(e));
        return null;
    }

    JobManagerProfiler profiler = null;

    try {

        final Constructor<JobManagerProfiler> constr = (Constructor<JobManagerProfiler>) profilerClass
                .getConstructor(InetAddress.class);
        profiler = constr.newInstance(jobManagerBindAddress);

    } catch (InvocationTargetException e) {
        LOG.error("Cannot create profiler: " + StringUtils.stringifyException(e));
        return null;
    } catch (NoSuchMethodException e) {
        LOG.error("Cannot create profiler: " + StringUtils.stringifyException(e));
        return null;
    } catch (InstantiationException e) {
        LOG.error("Cannot create profiler: " + StringUtils.stringifyException(e));
        return null;
    } catch (IllegalAccessException e) {
        LOG.error("Cannot create profiler: " + StringUtils.stringifyException(e));
        return null;
    } catch (IllegalArgumentException e) {
        LOG.error("Cannot create profiler: " + StringUtils.stringifyException(e));
        return null;
    }

    return profiler;
}

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From source file:fr.mby.saml2.sp.impl.helper.SecurityHelper.java

/**
 * Build a private Key from DER resource.
 * //from   w  ww .  j a v  a 2s.c  o  m
 * @param certificate
 *            the DER resource
 * @param pkSpecClass
 *            the java key specification class
 * @param type
 *            the certificate type
 * @return the java.security.cert.Certificate
 * @throws NoSuchMethodException
 * @throws SecurityException
 * @throws InvocationTargetException
 * @throws IllegalAccessException
 * @throws InstantiationException
 * @throws IllegalArgumentException
 * @throws NoSuchAlgorithmException
 * @throws InvalidKeySpecException
 * @throws IOException
 */
public static PrivateKey buildPrivateKey(final Resource privateKey, final Class<EncodedKeySpec> pkSpecClass,
        final String type) throws SecurityException, NoSuchMethodException, IllegalArgumentException,
        InstantiationException, IllegalAccessException, InvocationTargetException, NoSuchAlgorithmException,
        InvalidKeySpecException, IOException {
    PrivateKey result = null;

    final Constructor<EncodedKeySpec> keySpecConstructor = pkSpecClass.getConstructor(byte[].class);
    final byte[] keyBytes = SecurityHelper.readBytesFromFilePath(privateKey);
    if (keyBytes != null) {
        final EncodedKeySpec keySpec = keySpecConstructor.newInstance(keyBytes);
        final KeyFactory pkFactory = KeyFactory.getInstance(type);
        result = pkFactory.generatePrivate(keySpec);
    }

    return result;
}

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From source file:edu.brown.pools.TypedPoolableObjectFactory.java

/**
 * @param <X>//from  w ww.  ja v  a 2 s  .  c  o m
 * @param clazz
 * @param enable_tracking
 * @param args
 * @return
 */
public static <X extends Poolable> TypedPoolableObjectFactory<X> makeFactory(final Class<X> clazz,
        final boolean enable_tracking, final Object... args) {
    Class<?> argsClazz[] = new Class[args.length];
    for (int i = 0; i < args.length; i++) {
        assert (args[i] != null) : "[" + i + "]";
        argsClazz[i] = args[i].getClass();
    } // FOR
    final Constructor<X> constructor = ClassUtil.getConstructor(clazz, argsClazz);
    return new TypedPoolableObjectFactory<X>(enable_tracking) {
        @Override
        public X makeObjectImpl() throws Exception {
            return (constructor.newInstance(args));
        }
    };
}

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