org.scijava.util.MiscUtils Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of scijava-common Show documentation

SciJava Common is a shared library for SciJava software. It provides a plugin framework, with an extensible mechanism for service discovery, backed by its own annotation processor, so that plugins can be loaded dynamically. It is used by downstream projects in the SciJava ecosystem, such as ImageJ and SCIFIO.

There is a newer version: 2.99.0

Show newest version

/*
 * #%L
 * SciJava Common shared library for SciJava software.
 * %%
 * Copyright (C) 2009 - 2017 Board of Regents of the University of
 * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
 * Institute of Molecular Cell Biology and Genetics.
 * %%
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * #L%
 */

package org.scijava.util;

import java.util.Objects;

/**
 * Miscellaneous utility methods. Every project needs a class like this, right?
 * 
 * @author Curtis Rueden
 */
public final class MiscUtils {

	private MiscUtils() {
		// prevent instantiation of utility class
	}

	/**
	 * Compares two comparable objects, even if one or both of them are null.
	 * 
	 * By convention, nulls are considered less than non-nulls (and will hence
	 * will appear first on sorted lists).
	 * 
	 * 
	 * @param o1 The first object to compare.
	 * @param o2 The second object to compare.
	 * @return The result of {@code o1.compareTo(o2)} unless one or both of them
	 *         is null, in which case nulls are considered less than non-null
	 *         objects.
	 */
	public static > int compare(final T o1,
		final T o2)
	{
		return compare(o1, o2, false);
	}

	/**
	 * Compares two comparable objects, even if one or both of them are null.
	 * 
	 * @param o1 The first object to compare.
	 * @param o2 The second object to compare.
	 * @param heavyNulls If true, nulls will be treated as greater than non-nulls,
	 *          and hence "sink to the bottom" of e.g. sorted lists.
	 * @return The result of {@code o1.compareTo(o2)} unless one or both of them
	 *         is null, in which case the null strategy defined by the
	 *         {@code heavyNulls} flag is used, to define nulls as either less
	 *         than, or greater than, non-null objects.
	 */
	public static > int compare(final T o1,
		final T o2, final boolean heavyNulls)
	{
		if (o1 == null && o2 == null) return 0;
		if (o1 == null) return heavyNulls ? 1 : -1;
		if (o2 == null) return heavyNulls ? -1 : 1;
		return o1.compareTo(o2);
	}

	/**
	 * @deprecated Use {@link Objects#equals(Object, Object)} instead.
	 */
	@Deprecated
	public static boolean equal(final Object o1, final Object o2) {
		return o1 == null ? o2 == null : o1.equals(o2);
	}

}