edu.stanford.nlp.util.ErasureUtils.java Source code

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Here is the source code for edu.stanford.nlp.util.ErasureUtils.java

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package edu.stanford.nlp.util;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

/**
 * Class to gather unsafe operations into one place.
 * @author dlwh
 *
 */
public class ErasureUtils {
    private ErasureUtils() {
    }

    /**
     *  Casts an Object to a T
     * @param <T>
     */
    @SuppressWarnings("unchecked")
    public static <T> T uncheckedCast(Object o) {
        return (T) o;
    }

    /**
     * Does nothing, occasionally used to make Java happy that a value is used
     */
    public static void noop(Object o) {
    }

    /**
     * Makes an array based on klass, but casts it to be of type T[]. This is a very
     * unsafe operation and should be used carefully. Namely, you should ensure that
     * klass is a subtype of T, or that klass is a supertype of T *and* that the array
     * will not escape the generic constant *and* that klass is the same as the erasure
     * of T.
     * @param <T>
     */
    @SuppressWarnings("unchecked")
    public static <T> T[] mkTArray(Class<?> klass, int size) {
        return (T[]) (Array.newInstance(klass, size));

    }

    @SuppressWarnings("unchecked")
    public static <T> T[][] mkT2DArray(Class<?> klass, int[] dim) {
        if (dim.length != 2)
            throw new RuntimeException("dim should be an array of size 2.");
        return (T[][]) (Array.newInstance(klass, dim));
    }

    @SuppressWarnings("unchecked")
    public static <T> List<T> sortedIfPossible(Collection<T> collection) {
        List<T> result = new ArrayList<>(collection);
        try {
            Collections.sort((List) result);
        } catch (ClassCastException e) {
            // unable to sort, just return the copy
        } catch (NullPointerException npe) {
            // this happens if there are null elements in the collection; just return the copy
        }
        return result;
    }
}