Example usage for java.lang Class isInstance

Introduction

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

Prototype

@HotSpotIntrinsicCandidate
public native boolean isInstance(Object obj);

Source Link

Document

Determines if the specified Object is assignment-compatible with the object represented by this Class .

Usage

From source file:Main.java

@Nullable
public static <E> E firstElementOfType(@Nonnull final Class<E> type,
        @Nonnull final Iterable<? super E> elements) {

    for (final Object element : elements)
        if (type.isInstance(element))
            return type.cast(element);

    return null;//ww  w .j av  a2 s.co m
}

From source file:Main.java

private static <T> T search(Object[] objs, Class c) {
    for (Object o : objs) {
        if (c.isInstance(o))
            return (T) o;
    }/* w w  w  .  ja v  a2  s .co  m*/
    return null;
}

From source file:Main.java

/**
 * filter list of random types and only return only the matching type
 *
 * @param <T>//  ww  w .  ja  va  2 s  .c  o m
 * @param clazz
 * @param values
 * @return list of <T>
 */
public static <T> ArrayList<T> filterType(Class<T> clazz, Iterable<?> values) {
    ArrayList<T> list = new ArrayList<T>();
    for (Object o : values) {
        if (clazz.isInstance(o)) {
            list.add(clazz.cast(o));
        }
    }
    return list;
}

From source file:Main.java

public static <T> T getClassByName(String className, Class<T> classOfT) {
    try {/*from w  ww  . j a  v  a  2s  .  c o m*/
        Class<?> clazz = Class.forName(className);
        Object instance = clazz.newInstance();
        if (classOfT.isInstance(instance)) {
            return classOfT.cast(instance);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

From source file:Main.java

public static <T extends Component> void addChildren(Class<T> clazz, Collection<? super T> dst,
        Container parent) {/*from w ww .  j  a  v  a 2s.c  om*/
    for (Component c : parent.getComponents()) {
        if (clazz.isInstance(c))
            dst.add(clazz.cast(c));
    }
}

From source file:Main.java

/**
 Quick checks for <em>possibly</em> determining equality of two objects.
        /*from  w ww  .j a v  a 2 s.c o m*/
 <P>This method exists to make <tt>equals</tt> implementations read more legibly,
 and to avoid multiple <tt>return</tt> statements.
        
 <P><em>It cannot be used by itself to fully implement <tt>equals</tt>. </em>
 It uses <tt>==</tt> and <tt>instanceof</tt> to determine if equality can be
 found cheaply, without the need to examine field values in detail. It is
 <em>always</em> paired with some other method
 (usually {@link #equalsFor(Object[], Object[])}), as in the following example :
 <PRE>
 public boolean equals(Object aThat){
   Boolean result = ModelUtil.quickEquals(this, aThat);
   <b>if ( result == null ){</b>
 //quick checks not sufficient to determine equality,
 //so a full field-by-field check is needed :
 This this = (This) aThat; //will not fail
 result = ModelUtil.equalsFor(this.getSignificantFields(), that.getSignificantFields());
   }
   return result;
 }
 </PRE>
        
 <P>This method is unusual since it returns a <tt>Boolean</tt> that takes
 <em>3</em> values : <tt>true</tt>, <tt>false</tt>, and <tt>null</tt>. Here,
 <tt>true</tt> and <tt>false</tt> mean that a simple quick check was able to
 determine equality. <span class='highlight'>The <tt>null</tt> case means that the
 quick checks were not able to determine if the objects are equal or not, and that
 further field-by-field examination is necessary. The caller must always perform a
 check-for-null on the return value.</span>
 */
static public Boolean quickEquals(Object aThis, Object aThat) {

    Boolean result = null;

    if (aThis == aThat) {

        result = Boolean.TRUE;
    } else {

        Class<?> thisClass = aThis.getClass();

        if (!thisClass.isInstance(aThat)) {

            result = Boolean.FALSE;
        }
    }

    return result;
}

From source file:Main.java

/**
 * Finds the first object in the heterogeneous list that is an instance of 
 * the given class, removes it from the list, and returns it.
 * If there is not object in the list of the given type the list is left
 * unmodified and null is returned.//from   www . j  av a  2  s. c  o  m
 * 
 * @throws NullPointerException if list or clazz is null
 * @throws UnsupportedOperationException if the list's Iterator does not support the remove()
 *     method
 */
@SuppressWarnings("unchecked")
public static <T> T findFirstAndRemove(List<?> list, Class<T> clazz) {
    for (Iterator<?> iter = list.iterator(); iter.hasNext();) {
        Object o = iter.next();
        if (clazz.isInstance(o)) {
            iter.remove();
            return (T) o; // safe
        }
    }
    return null;
}

From source file:Main.java

public static <T> Collection<T> filter(final Collection<?> objects, final Class<T> filterType) {
    final Collection<T> filtered = new ArrayList<T>();
    for (final Object object : objects) {
        if (filterType.isInstance(object)) {
            filtered.add(filterType.cast(object));
        }/*from  ww  w  .j a v a  2s  .c o m*/
    }
    return filtered;
}

From source file:org.vaadin.spring.security.util.SecurityExceptionUtils.java

private static boolean hasExceptionOfTypeInChain(Class<? extends Throwable> type, Throwable throwable) {
    if (throwable == null) {
        return false;
    } else if (type.isInstance(throwable)) {
        return true;
    } else {/*  ww w.  j  ava 2  s  . co m*/
        return hasExceptionOfTypeInChain(type, throwable.getCause());
    }
}

From source file:Main.java

/**
 * Generic-ified version of SwingUtilities.getAncestorOfClass()
 *///from w  w  w  .  j a v a2 s. c  om
public static <T> T getAncestorOfClass(Class<T> c, Component comp) {
    if (comp == null || c == null)
        return null;
    Container parent = comp.getParent();
    while (parent != null && !(c.isInstance(parent)))
        parent = parent.getParent();
    return (T) parent;
}