org.hamcrest.core.IsNot Maven / Gradle / Ivy

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/*  Copyright (c) 2000-2009 hamcrest.org
 */
package org.hamcrest.core;

import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;
import org.hamcrest.Factory;
import org.hamcrest.Matcher;

import static org.hamcrest.core.IsEqual.equalTo;


/**
 * Calculates the logical negation of a matcher.
 */
public class IsNot extends BaseMatcher  {
    private final Matcher matcher;

    public IsNot(Matcher matcher) {
        this.matcher = matcher;
    }

    @Override
    public boolean matches(Object arg) {
        return !matcher.matches(arg);
    }

    @Override
    public void describeTo(Description description) {
        description.appendText("not ").appendDescriptionOf(matcher);
    }

    
    /**
     * Creates a matcher that wraps an existing matcher, but inverts the logic by which
     * it will match.
     * 
     * For example:
     * 
assertThat(cheese, is(not(equalTo(smelly))))
     * 
     * @param matcher
     *     the matcher whose sense should be inverted
     */
    @Factory
    public static  Matcher not(Matcher matcher) {
        return new IsNot(matcher);
    }

    /**
     * A shortcut to the frequently used not(equalTo(x)).
     * 
     * For example:
     * 
assertThat(cheese, is(not(smelly)))
     * instead of:
     * assertThat(cheese, is(not(equalTo(smelly))))
     * 
     * @param value
     *     the value that any examined object should not equal
     */
    @Factory
    public static  Matcher not(T value) {
        return not(equalTo(value));
    }
}