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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.
/*
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* SciJava Common shared library for SciJava software.
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* Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
* Institute of Molecular Cell Biology and Genetics.
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
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package org.scijava.util;
/**
* 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);
}
/**
* Compares two objects for equality, even if one or both of them are null.
*
* @param o1 The first object to compare.
* @param o2 The second object to compare.
* @return True if the two objects are both null, or both are non-null and
* {@code o1.equals(o2)} holds.
*/
public static boolean equal(final Object o1, final Object o2) {
if (o1 == null && o2 == null) return true;
if (o1 == null || o2 == null) return false;
return o1.equals(o2);
}
}