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:demo.config.PropertyConverter.java

/**
 * Tries to convert the specified object into a number object. This method
 * is used by the conversion methods for number types. Note that the return
 * value is not in always of the specified target class, but only if a new
 * object has to be created./*from   w  ww . j a  va2s  .c  om*/
 * 
 * @param value
 *            the value to be converted (must not be <b>null</b>)
 * @param targetClass
 *            the target class of the conversion (must be derived from
 *            {@code java.lang.Number})
 * @return the converted number
 * @throws ConversionException
 *             if the object cannot be converted
 */
static Number toNumber(Object value, Class<?> targetClass) throws ConversionException {
    if (value instanceof Number) {
        return (Number) value;
    } else {
        String str = value.toString();
        if (str.startsWith(HEX_PREFIX)) {
            try {
                return new BigInteger(str.substring(HEX_PREFIX.length()), HEX_RADIX);
            } catch (NumberFormatException nex) {
                throw new ConversionException(
                        "Could not convert " + str + " to " + targetClass.getName() + "! Invalid hex number.",
                        nex);
            }
        }

        if (str.startsWith(BIN_PREFIX)) {
            try {
                return new BigInteger(str.substring(BIN_PREFIX.length()), BIN_RADIX);
            } catch (NumberFormatException nex) {
                throw new ConversionException("Could not convert " + str + " to " + targetClass.getName()
                        + "! Invalid binary number.", nex);
            }
        }

        try {
            Constructor<?> constr = targetClass.getConstructor(CONSTR_ARGS);
            return (Number) constr.newInstance(new Object[] { str });
        } catch (InvocationTargetException itex) {
            throw new ConversionException("Could not convert " + str + " to " + targetClass.getName(),
                    itex.getTargetException());
        } catch (Exception ex) {
            // Treat all possible exceptions the same way
            throw new ConversionException(
                    "Conversion error when trying to convert " + str + " to " + targetClass.getName(), ex);
        }
    }
}

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From source file:com.asual.summer.core.util.ClassUtils.java

public static Object newInstance(String clazz, Object... parameters)
        throws SecurityException, ClassNotFoundException {
    Class<?>[] classParameters = new Class[parameters == null ? 0 : parameters.length];
    for (int i = 0; i < classParameters.length; i++) {
        classParameters[i] = parameters[i].getClass();
    }/*from  w  w  w.j a v a2s. co  m*/
    Object instance = null;
    try {
        instance = Class.forName(clazz).getConstructor(classParameters)
                .newInstance(parameters == null ? new Object[] {} : parameters.length);
    } catch (Exception e) {
        Constructor<?>[] constructors = Class.forName(clazz).getConstructors();
        for (Constructor<?> constructor : constructors) {
            Class<?>[] types = constructor.getParameterTypes();
            if (types.length == parameters.length) {
                Object[] params = new Object[parameters.length];
                for (int i = 0; i < parameters.length; i++) {
                    if (types[i] == boolean.class || types[i] == Boolean.class) {
                        params[i] = Boolean.valueOf(parameters[i].toString());
                    } else if (types[i] == int.class || types[i] == Integer.class) {
                        params[i] = Integer.valueOf(parameters[i].toString());
                    } else {
                        params[i] = types[i].cast(parameters[i]);
                    }
                }
                try {
                    instance = constructor.newInstance(params);
                    break;
                } catch (Exception ex) {
                    continue;
                }
            }
        }
    }
    return instance;
}

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From source file:com.helpinput.utils.Utils.java

public static <T> T constructorNewInstance(Class<T> classType, Object... agrs) {
    if (agrs == null) {
        try {/*from  ww w .j  a v  a  2s. co m*/
            return classType.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }
    Constructor<?> cst = findConstructor(classType, agrs);
    if (cst != null) {
        try {
            @SuppressWarnings("unchecked")
            T instance = (T) cst.newInstance(agrs);
            return instance;
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    return null;
}

---

From source file:demo.config.PropertyConverter.java

/**
 * Convert the specified value into an email address.
 * //from   w ww.j  a  v a  2 s . com
 * @param value
 *            the value to convert
 * @return the converted value
 * @throws ConversionException
 *             thrown if the value cannot be converted to an email address
 * 
 * @since 1.5
 */
static Object toInternetAddress(Object value) throws ConversionException {
    if (value.getClass().getName().equals(INTERNET_ADDRESS_CLASSNAME)) {
        return value;
    } else if (value instanceof String) {
        try {
            Constructor<?> ctor = Class.forName(INTERNET_ADDRESS_CLASSNAME)
                    .getConstructor(new Class[] { String.class });
            return ctor.newInstance(new Object[] { value });
        } catch (Exception e) {
            throw new ConversionException("The value " + value + " can't be converted to a InternetAddress", e);
        }
    } else {
        throw new ConversionException("The value " + value + " can't be converted to a InternetAddress");
    }
}

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From source file:com.helpinput.core.Utils.java

public static <T> T newInstance(Class<T> classType, Object... args) {
    if (!hasLength(args)) {
        try {/*from w  ww. j  av  a2 s . c  o m*/
            return classType.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }
    Constructor<?> cst = findConstructor(classType, args);
    if (cst != null) {
        try {
            @SuppressWarnings("unchecked")
            T instance = (T) cst.newInstance(args);
            return instance;
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    return null;
}

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From source file:com.nickandjerry.dynamiclayoutinflator.DynamicLayoutInflator.java

private static View getViewForName(Context context, String name) {
    try {/*w ww  .  j  ava 2s .  co  m*/
        if (!name.contains(".")) {
            name = "android.widget." + name;
        }
        Class<?> clazz = Class.forName(name);
        Constructor<?> constructor = clazz.getConstructor(Context.class);
        return (View) constructor.newInstance(context);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return null;
}

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From source file:net.sf.ehcache.config.BeanHandler.java

/**
 * Creates a child object.//from ww  w .j  ava2s .  c o m
 */
private static Object createInstance(Object parent, Class childClass) throws Exception {
    final Constructor[] constructors = childClass.getConstructors();
    ArrayList candidates = new ArrayList();
    for (int i = 0; i < constructors.length; i++) {
        final Constructor constructor = constructors[i];
        final Class[] params = constructor.getParameterTypes();
        if (params.length == 0) {
            candidates.add(constructor);
        } else if (params.length == 1 && params[0].isInstance(parent)) {
            candidates.add(constructor);
        }
    }
    switch (candidates.size()) {
    case 0:
        throw new Exception("No constructor for class " + childClass.getName());
    case 1:
        break;
    default:
        throw new Exception("Multiple constructors for class " + childClass.getName());
    }

    final Constructor constructor = (Constructor) candidates.remove(0);
    if (constructor.getParameterTypes().length == 0) {
        return constructor.newInstance(new Object[] {});
    } else {
        return constructor.newInstance(new Object[] { parent });
    }
}

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From source file:dk.netarkivet.archive.webinterface.BatchGUI.java

/**
 * Method for executing a batchjob./*from w  ww.  j a v  a2 s.com*/
 *
 * @param context The page context containing the needed information for executing the batchjob.
 */
@SuppressWarnings("rawtypes")
public static void execute(PageContext context) {
    try {
        ServletRequest request = context.getRequest();

        // get parameters
        String filetype = request.getParameter(Constants.FILETYPE_PARAMETER);
        String jobId = request.getParameter(Constants.JOB_ID_PARAMETER);
        String jobName = request.getParameter(Constants.BATCHJOB_PARAMETER);
        String repName = request.getParameter(Constants.REPLICA_PARAMETER);

        FileBatchJob batchjob;

        // Retrieve the list of arguments.
        List<String> args = new ArrayList<String>();
        String arg;
        Integer i = 1;
        // retrieve the constructor to find out how many arguments
        Class c = getBatchClass(jobName);
        Constructor con = findStringConstructor(c);

        // retrieve the arguments and put them into the list.
        while (i <= con.getParameterTypes().length) {
            arg = request.getParameter("arg" + i.toString());
            if (arg != null) {
                args.add(arg);
            } else {
                log.warn("Should contain argument number " + i + ", but "
                        + "found a null instead, indicating missing " + "argument. Use empty string instead.");
                args.add("");
            }
            i++;
        }

        File jarfile = getJarFile(jobName);
        if (jarfile == null) {
            // get the constructor and instantiate it.
            Constructor construct = findStringConstructor(getBatchClass(jobName));
            batchjob = (FileBatchJob) construct.newInstance(args.toArray());
        } else {
            batchjob = new LoadableJarBatchJob(jobName, args, jarfile);
        }

        // get the regular expression.
        String regex = jobId + "-";
        if (filetype.equals(BatchFileType.Metadata.toString())) {
            regex += Constants.REGEX_METADATA;
        } else if (filetype.equals(BatchFileType.Content.toString())) {
            // TODO fix this 'content' regex. (NAS-1394)
            regex += Constants.REGEX_CONTENT;
        } else {
            regex += Constants.REGEX_ALL;
        }

        // validate the regular expression (throws exception if wrong).
        Pattern.compile(regex);

        Replica rep = Replica.getReplicaFromName(repName);

        new BatchExecuter(batchjob, regex, rep).start();

        JspWriter out = context.getOut();
        out.write("Executing batchjob with the following parameters. " + "<br/>\n");
        out.write("BatchJob name: " + jobName + "<br/>\n");
        out.write("Replica: " + rep.getName() + "<br/>\n");
        out.write("Regular expression: " + regex + "<br/>\n");
    } catch (Exception e) {
        throw new IOFailure("Could not instantiate the batchjob.", e);
    }
}

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From source file:br.com.binarti.simplesearchexpr.converter.NumberSearchDataConverter.java

@SuppressWarnings("rawtypes")
@Override/*from w w w .ja  va 2  s  .c  o m*/
protected Object asSingleObject(SimpleSearchExpressionField field, String value, Map<String, Object> params,
        Class<?> targetType) {
    if (value == null)
        return null;
    if (targetType.isPrimitive()) {
        targetType = ClassUtils.primitiveToWrapper(targetType);
    }
    try {
        Constructor constructor = targetType.getConstructor(String.class);
        return constructor.newInstance(value.trim());
    } catch (Exception e) {
        throw new SimpleSearchDataConverterException(
                "Error converter " + value + " to " + targetType.getClass());
    }
}

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From source file:com.sequenceiq.ambari.shell.converter.AbstractConverter.java

@Override
public T convertFromText(String value, Class<?> clazz, String optionContext) {
    try {// w  w  w.j a  va2s  .c  o m
        Constructor<?> constructor = clazz.getDeclaredConstructor(String.class);
        return (T) constructor.newInstance(value);
    } catch (Exception e) {
        return null;
    }
}

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