com.forerunnergames.tools.common.Utils.java Source code

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Here is the source code for com.forerunnergames.tools.common.Utils.java

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/*
 * Copyright  2011 - 2013 Aaron Mahan
 * Copyright  2013 - 2016 Forerunner Games, LLC
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.forerunnergames.tools.common;

import com.google.common.base.Optional;
import com.google.common.collect.Multimap;

import javax.annotation.Nullable;

public final class Utils {
    /**
     * Finds the key from its associated value in a multiMap.
     *
     * @param value
     *          The value whose key is to be searched for.
     * @param multiMap
     *          The multiMap to search in.
     *
     * @return The key, if found; Integer.MIN_VALUE otherwise.
     */
    public static int findKeyFromValue(final int value, Multimap<Integer, Integer> multiMap) {
        Arguments.checkIsNotNull(value, "value");
        Arguments.checkIsNotNull(multiMap, "multiMap");

        boolean foundKey = false;

        java.util.Iterator<Integer> keyIterator = multiMap.keySet().iterator();

        Integer boxedKey = Integer.MIN_VALUE;
        Integer boxedValue = Integer.valueOf(value);

        while (keyIterator.hasNext() && !foundKey) {
            boxedKey = keyIterator.next();

            if (multiMap.containsEntry(boxedKey, boxedValue))
                foundKey = true;
        }

        assert foundKey;

        return boxedKey;
    }

    /**
     * Checks whether the double n is equal to a mathematical integer.
     * <p/>
     * If n is infinite, or NaN, this method will return false. If n is positive or negative zero, this method will return
     * true.
     *
     * @param n
     *          The double to check.
     *
     * @return True if n is equal to a mathematical integer, false otherwise.
     */
    public static boolean isInteger(final double n) {
        return !Double.isInfinite(n) && !Double.isNaN(n) && Math.floor(n) == n;
    }

    /**
     * Cause the current thread to sleep for the specified number of milliseconds.
     * <p/>
     * This method is interrupt-friendly (i.e. allows interruption).
     *
     * @param milliseconds
     *          The number of milliseconds to sleep for, must be greater than zero.
     *
     * @throws IllegalArgumentException
     *           If milliseconds is less than or equal to zero.
     * @see Time
     */
    public static void sleep(final long milliseconds) {
        Arguments.checkLowerExclusiveBound(milliseconds, 0, "Milliseconds");

        try {
            Thread.sleep(milliseconds);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * Attempts to cast the specified object to the specified type, returning an {@link Optional} to avoid
     * {@link ClassCastException} & {@link NullPointerException} in cases where the cast is not possible.
     *
     * @param object
     *          The object to cast, may be null.
     * @param objectType
     *          The class of the type to cast the specified object to, must not be null.
     * @param <T>
     *          The type to cast the specified object to.
     *
     * @return An {@link Optional} that will contain the casted object if the specified object was successfully able to be
     *         cast to the specified type, i.e., {@link Optional#isPresent()} will return true & {@link Optional#get ()}
     *         will return the cast object, otherwise {@link Optional#isPresent()} will return false &
     *         {@link Optional#get()} will throw an {@link IllegalStateException}.
     */
    public static <T> Optional<T> optionalCast(@Nullable final Object object, final Class<T> objectType) {
        Arguments.checkIsNotNull(objectType, "objectType");

        return objectType.isInstance(object) ? Optional.of(objectType.cast(object)) : Optional.<T>absent();
    }

    private Utils() {
        Classes.instantiationNotAllowed();
    }
}