Example usage for java.lang Class getConstructor

Introduction

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

Prototype

@CallerSensitive
public Constructor<T> getConstructor(Class<?>... parameterTypes)
        throws NoSuchMethodException, SecurityException 

Source Link

Document

Returns a Constructor object that reflects the specified public constructor of the class represented by this Class object.

Usage

From source file:Main.java

/**
 * Because of a BUG of Android (API 13-),
 * get signature info by using "getPackageArchiveInfo" of "PackageManager"
 * always causes "NullPointerException".
 * Lack of code in method "getPackageArchiveInfo":
 *     if ((flags & GET_SIGNATURES) != 0)
 *     {/*www. j a  v a  2s  .  c om*/
 *         packageParser.collectCertificates(pkg, 0);
 *     }
 */
@SuppressWarnings("unchecked")
public static PackageInfo getPackageArchiveInfo(String archiveFilePath, int flags) {
    try {
        Class packageParserClass = Class.forName("android.content.pm.PackageParser");
        Class[] innerClasses = packageParserClass.getDeclaredClasses();
        Class packageParserPackageClass = null;
        for (Class innerClass : innerClasses) {
            if (0 == innerClass.getName().compareTo("android.content.pm.PackageParser$Package")) {
                packageParserPackageClass = innerClass;
                break;
            }
        }
        Constructor packageParserConstructor = packageParserClass.getConstructor(String.class);
        Method parsePackageMethod = packageParserClass.getDeclaredMethod("parsePackage", File.class,
                String.class, DisplayMetrics.class, int.class);
        Method collectCertificatesMethod = packageParserClass.getDeclaredMethod("collectCertificates",
                packageParserPackageClass, int.class);
        Method generatePackageInfoMethod = packageParserClass.getDeclaredMethod("generatePackageInfo",
                packageParserPackageClass, int[].class, int.class, long.class, long.class);
        packageParserConstructor.setAccessible(true);
        parsePackageMethod.setAccessible(true);
        collectCertificatesMethod.setAccessible(true);
        generatePackageInfoMethod.setAccessible(true);

        Object packageParser = packageParserConstructor.newInstance(archiveFilePath);

        DisplayMetrics displayMetrics = new DisplayMetrics();
        displayMetrics.setToDefaults();

        final File sourceFile = new File(archiveFilePath);

        Object pkg = parsePackageMethod.invoke(packageParser, sourceFile, archiveFilePath, displayMetrics, 0);
        if (pkg == null) {
            return null;
        }

        if ((flags & PackageManager.GET_SIGNATURES) != 0) {
            collectCertificatesMethod.invoke(packageParser, pkg, 0);
        }

        return (PackageInfo) generatePackageInfoMethod.invoke(null, pkg, null, flags, 0, 0);
    } catch (Exception e) {
        e.printStackTrace();
    }

    return null;
}

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From source file:azkaban.common.utils.Utils.java

/**
 * Call the class constructor with the given arguments
 * //from   w w  w.  j  av a 2  s . c o  m
 * @param c The class
 * @param args The arguments
 * @return The constructed object
 */
public static Object callConstructor(Class<?> c, Class<?>[] argTypes, Object[] args) {
    try {
        Constructor<?> cons = c.getConstructor(argTypes);
        return cons.newInstance(args);
    } catch (InvocationTargetException e) {
        throw getCause(e);
    } catch (IllegalAccessException e) {
        throw new IllegalStateException(e);
    } catch (NoSuchMethodException e) {
        throw new IllegalStateException(e);
    } catch (InstantiationException e) {
        throw new IllegalStateException(e);
    }
}

---

From source file:net.buffalo.protocal.util.ClassUtil.java

public static Object convertValue(Object value, Class targetType) {

    if (value.getClass().equals(targetType))
        return value;

    if (targetType.isPrimitive()) {
        targetType = getWrapperClass(targetType);
    }// ww w. ja v a2s. co  m

    if (targetType.isAssignableFrom(value.getClass()))
        return value;

    if ((value instanceof String || value instanceof Number) && Number.class.isAssignableFrom(targetType)) {
        try {
            Constructor ctor = targetType.getConstructor(new Class[] { String.class });
            return ctor.newInstance(new Object[] { value.toString() });
        } catch (Exception e) {
            LOGGER.error("convert type error", e);
            throw new RuntimeException(
                    "Cannot convert from " + value.getClass().getName() + " to " + targetType, e);
        }
    }

    if (targetType.isArray() && Collection.class.isAssignableFrom(value.getClass())) {
        Collection collection = (Collection) value;
        Object array = Array.newInstance(targetType.getComponentType(), collection.size());
        int i = 0;
        for (Iterator iter = collection.iterator(); iter.hasNext();) {
            Object val = iter.next();
            Array.set(array, i++, val);
        }

        return array;
    }

    if (Collection.class.isAssignableFrom(targetType) && value.getClass().isArray()) {
        return Arrays.asList((Object[]) value);
    }

    throw new IllegalArgumentException(
            "Cannot convert from " + value.getClass().getName() + " to " + targetType);
}

---

From source file:com.google.gdt.eclipse.designer.mac.BrowserShellMacImplCocoa.java

private static Image createImageFromHandle(long imageHandle, int width, int height) throws Exception {
    if (imageHandle != 0) {
        Class<?> nsImageClass = Class.forName("org.eclipse.swt.internal.cocoa.NSImage");
        Object handleObject;//w w  w. j  a  va  2 s .co m
        Class<?> handleClass;
        if (SystemUtils.OS_ARCH.indexOf("64") != -1) {
            handleClass = long.class;
            handleObject = new Long(imageHandle);
        } else {
            handleClass = int.class;
            handleObject = new Integer((int) imageHandle);
        }
        Constructor<?> constructor = nsImageClass.getConstructor(handleClass);
        Object nsImage = constructor.newInstance(handleObject);
        // Create a temporary image using the captured image's handle
        Class<?> NSImageClass = Class.forName("org.eclipse.swt.internal.cocoa.NSImage");
        Method method = Image.class.getDeclaredMethod("cocoa_new",
                new Class[] { Device.class, int.class, NSImageClass });
        method.setAccessible(true);
        Image tempImage = (Image) method.invoke(null,
                new Object[] { Display.getCurrent(), new Integer(SWT.BITMAP), nsImage });
        // Create the result image
        Image image = new Image(Display.getCurrent(), width, height);
        // Manually copy because the image's data handle isn't available
        GC gc = new GC(tempImage);
        gc.copyArea(image, 0, 0);
        gc.dispose();
        // Dispose of the temporary image allocated in the native call
        tempImage.dispose();
        return image;
    }
    // prevent failing
    return new Image(Display.getCurrent(), 1, 1);
}

---

From source file:edu.usc.pgroup.floe.utils.Utils.java

/**
 * Use reflection to create an instance of the given class.
 * @param fqdnClassName the fully qualified class name.
 * @param params types of parameters to query for the constructor.
 * @return a new instance of the given class. NULL if there was an error
 * creating the instance.//from  ww w.j a v  a 2 s  .  co  m
 */
public static Constructor<?> getConstructor(final String fqdnClassName, final Class<?>... params) {
    try {
        Class<?> klass = Class.forName(fqdnClassName);

        return klass.getConstructor(params);

    } catch (ClassNotFoundException e) {
        LOGGER.error("Could not create an instance of {}, Exception:{}", fqdnClassName, e);
    } catch (NoSuchMethodException e) {
        LOGGER.error("No such constructor found, Exception:{}", fqdnClassName, e);
    }
    return null;
}

---

From source file:com.expressui.core.util.ReflectionUtil.java

/**
 * Converts object value to given type. Converts primitives to their wrappers.
 * Converts strings to numbers./*from  ww w. j a  va 2 s.c  om*/
 *
 * @param value value to convert
 * @param type  type to convert to
 * @param <T>   type
 * @return converted value
 * @throws InvocationTargetException
 * @throws IllegalAccessException
 * @throws InstantiationException
 * @throws NoSuchMethodException
 */
public static <T> T convertValue(Object value, Class<T> type) throws InvocationTargetException,
        IllegalAccessException, InstantiationException, NoSuchMethodException {
    Class clazz;
    if (type.isPrimitive()) {
        clazz = ClassUtils.primitiveToWrapper(type);
    } else {
        clazz = type;
    }

    if (null == value || clazz.isAssignableFrom(value.getClass())) {
        return (T) value;
    }

    Constructor<T> constructor = clazz.getConstructor(new Class[] { String.class });

    return constructor.newInstance(value.toString());
}

---

From source file:com.mobilyzer.util.MeasurementJsonConvertor.java

public static MeasurementTask makeMeasurementTaskFromJson(JSONObject json) throws IllegalArgumentException {
    try {// ww  w.  j  ava2 s  . c  om
        String type = String.valueOf(json.getString("type"));
        Class taskClass = MeasurementTask.getTaskClassForMeasurement(type);
        Method getDescMethod = taskClass.getMethod("getDescClass");
        // The getDescClassForMeasurement() is static and takes no arguments
        Class descClass = (Class) getDescMethod.invoke(null, (Object[]) null);
        MeasurementDesc measurementDesc = (MeasurementDesc) gson.fromJson(json.toString(), descClass);

        Object cstParam = measurementDesc;
        Constructor<MeasurementTask> constructor = taskClass.getConstructor(MeasurementDesc.class);
        return constructor.newInstance(cstParam);
    } catch (JSONException e) {
        throw new IllegalArgumentException(e);
    } catch (SecurityException e) {
        Logger.w(e.getMessage());
        throw new IllegalArgumentException(e);
    } catch (NoSuchMethodException e) {
        Logger.w(e.getMessage());
        throw new IllegalArgumentException(e);
    } catch (IllegalArgumentException e) {
        Logger.w(e.getMessage());
        throw new IllegalArgumentException(e);
    } catch (InstantiationException e) {
        Logger.w(e.getMessage());
        throw new IllegalArgumentException(e);
    } catch (IllegalAccessException e) {
        Logger.w(e.getMessage());
        throw new IllegalArgumentException(e);
    } catch (InvocationTargetException e) {
        Logger.w(e.toString());
        throw new IllegalArgumentException(e);
    }
}

---

From source file:com.austin.base.commons.util.ReflectUtil.java

/**
 * @param className ??/*from  ww w .  j  a v  a  2  s . co m*/
 * @param args 17?
 * @return 
 */
public static Object newInstance(String className, Object[] args)

{
    try {
        Class newoneClass = Class.forName(className);

        Class[] argsClass = new Class[args.length];

        for (int i = 0, j = args.length; i > j; i++) {
            argsClass[i] = args[i].getClass();
        }

        Constructor cons = newoneClass.getConstructor(argsClass);

        return cons.newInstance(args);
    } catch (Exception ex) {
        log.error(ex);
        return null;
    }

}

---

From source file:com.open.cas.shiro.util.ReflectionUtils.java

/**  
 *   /*from www .ja  v a  2s. com*/
 *  
 * @param className  
 *            ??  
 * @param args  
 *            ?  
 * @return   
 * @throws Exception  
 */
public static Object newInstance(Class clazz, Object[] args) {
    try {
        Class[] argsClass = new Class[args.length];
        for (int i = 0, j = args.length; i < j; i++) {
            argsClass[i] = args[i].getClass();
        }
        Constructor cons = clazz.getConstructor(argsClass);
        return cons.newInstance(args);
    } catch (Exception e) {
        throw convertReflectionExceptionToUnchecked(e);
    }
}

---

From source file:com.open.cas.shiro.util.ReflectionUtils.java

public static Object newInstance(String className, Object[] args) {
    try {/*w  w  w.jav a  2s.c  o  m*/
        Class newoneClass = Class.forName(className);
        Class[] argsClass = new Class[args.length];
        for (int i = 0, j = args.length; i < j; i++) {
            argsClass[i] = args[i].getClass();
        }
        Constructor cons = newoneClass.getConstructor(argsClass);
        return cons.newInstance(args);
    } catch (Exception e) {
        throw convertReflectionExceptionToUnchecked(e);
    }
}

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