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

private static Object getInstance(String name, Class<?> classParas[], Object paras[]) {
    Object o = null;/*from   w  w w .j  a  v a  2 s .  c  o m*/
    try {
        Class<?> c = Class.forName(name);
        Constructor<?> con = c.getConstructor(classParas);
        o = con.newInstance(paras);
    } catch (Exception ex) {
    }

    return o;
}

From source file:Main.java

public static void loadContext(android.content.Context context, Field field, Object object)
        throws IllegalAccessException, InvocationTargetException, InstantiationException,
        NoSuchMethodException {//ww w  .  ja v a2  s .  co m
    field.setAccessible(true);
    Class fType = (Class) field.getGenericType();
    Constructor constructor = fType.getConstructor(android.content.Context.class);
    if (constructor != null) {
        field.set(object, constructor.newInstance(context));
    }
}

From source file:Main.java

/**
 * Returns a filtered copy of the collection <code>coll</code>.
 *
 * @param coll the collection to filter.
 * @param p the predicate to filter by./*from   w  w  w  .  ja va 2 s .  c o  m*/
 * @return a new collection.
 */

/*public static <T> Collection<T> filter(Collection<T> coll, Predicate<T> p){
Collection<T> c2 = newCollection(coll);
for(T obj: coll)
    if(p.apply(obj))
        c2.add(obj);
return c2;
}*/

private static <T> Collection<T> cloneCollection(Collection<T> coll) {
    try {
        Class cl = coll.getClass();
        Constructor con = cl.getConstructor(new Class[] { Collection.class });
        return (Collection<T>) con.newInstance(new Object[] { coll });
    } catch (Exception e) {
        if (coll instanceof List)
            return new LinkedList<T>(coll);
        if (coll instanceof Set)
            return new HashSet<T>(coll);
        throw new RuntimeException("Cannot handle this collection");
    }
}

From source file:Main.java

public static <T> T loadObject(Element e, Class<T> type) throws InstantiationException, IllegalAccessException,
        InvocationTargetException, NoSuchMethodException, ClassNotFoundException {
    if (e != null) {
        String c = e.getAttribute("type");
        Class<T> clazz = (Class) Class.forName(c);
        Constructor<T> con = clazz.getConstructor((Class[]) null);
        return con.newInstance();
    }/*from  ww w. j  ava2 s  .  c  o m*/
    return null;
}

From source file:Main.java

public static Object newHandlerInstance(String clzPath, Class<?>[] parameterTypes, Object[] args) {
    try {//from   w w  w  . j  a  v  a  2s. c  o  m
        Class<?> clz = Class.forName(clzPath);
        Constructor<?> constructor = clz.getConstructor(parameterTypes);
        return constructor.newInstance(args);
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
    return null;
}

From source file:ReflectionUtils.java

public static boolean hasDeclaredConstructor(Class targetClass, Class[] partypes) {
    Constructor constructor = null;
    try {/*from  ww  w  .  j av a 2 s  . c  o m*/
        constructor = targetClass.getConstructor(partypes);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return constructor != null;
}

From source file:Main.java

public static List<String> getDexEntries() {
    try {//from w  ww .jav  a 2 s .  c  o m
        Object app = Class.forName("android.app.ActivityThread").getMethod("currentApplication").invoke(null);
        Object codePath = Class.forName("android.app.Application").getMethod("getPackageCodePath").invoke(app);
        Class<?> dexFileClass = Class.forName("dalvik.system.DexFile");
        Object dexFile = dexFileClass.getConstructor(String.class).newInstance(codePath);
        Enumeration<String> entries = (Enumeration<String>) dexFileClass.getMethod("entries").invoke(dexFile);
        List<String> dexEntries = new LinkedList<>();
        while (entries.hasMoreElements()) {
            String entry = entries.nextElement();
            entry = entry.replace('.', '/') + ".class";
            dexEntries.add(entry);
        }
        dexFileClass.getMethod("close").invoke(dexFile);
        return dexEntries;
    } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException
            | NoSuchMethodException | SecurityException | ClassNotFoundException | InstantiationException e) {
        throw new RuntimeException(e);
    }
}

From source file:Main.java

/**
 * Checks whether a {@code Constructor} object with no parameter types is specified
 * by the invoked {@code Class} object or not.
 *
 * @param clazz the {@code Class} object whose constructors are checked.
 * @return {@code true} if a {@code Constructor} object with no parameter types is specified.
 * @throws SecurityException If a security manager, <i>s</i> is present and any of the
 *         following conditions is met:/*from  w  w  w.  j a va  2  s  .  c om*/
 *         <ul>
 *             <li> invocation of
 *             {@link SecurityManager#checkMemberAccess
 *             s.checkMemberAccess(this, Member.PUBLIC)} denies
 *             access to the constructor
 *
 *             <li> the caller's class loader is not the same as or an
 *             ancestor of the class loader for the current class and
 *             invocation of {@link SecurityManager#checkPackageAccess
 *             s.checkPackageAccess()} denies access to the package
 *             of this class
 *         </ul>
 *
 * @see {@link Class#getConstructor(Class...)}
 */
public static boolean hasDefaultConstructor(Class<?> clazz) throws SecurityException {
    Class<?>[] empty = {};
    try {
        clazz.getConstructor(empty);
    } catch (NoSuchMethodException e) {
        return false;
    }
    return true;
}

From source file:Main.java

public static Constructor getConstructor(Class<?> targetClass, Class<?>... parameterTypes)
        throws NoSuchMethodException {
    Constructor constructor = targetClass.getConstructor(parameterTypes);
    constructor.setAccessible(true);/*from www.  j ava2s  .c om*/
    return constructor;
}

From source file:Main.java

/**
 * Creates a new empty instance of the provided collection
 * //  www.j  av a 2s  .com
 * @param <T>
 * @param in
 * @return
 */
public static <T> Collection<T> createEmpty(Collection<?> in) {
    Class<?> originalClass = in.getClass();
    try {
        Constructor<?> originalConstructor = originalClass.getConstructor(new Class[0]);
        return (Collection<T>) originalConstructor.newInstance(new Object[0]);
    } catch (IllegalArgumentException e) {
    } catch (InstantiationException e) {
    } catch (IllegalAccessException e) {
    } catch (InvocationTargetException e) {
    } catch (SecurityException e) {
    } catch (NoSuchMethodException e) {
    } finally {
        return null;
    }
}