10. 自定义assertThat中的Matcher函数lt、gt

package lesson10;

import org.junit.Test;
import static org.hamcrest.CoreMatchers.both;
import static org.junit.Assert.assertThat;

public class SimpleTest {
    @Test
    public void test() {
        assertThat(1, CompareNumberMatcher.lt(3));
        assertThat(10, CompareNumberMatcher.gt(3));
        assertThat(5, both(CompareNumberMatcher.gt(3)).and(CompareNumberMatcher.lt(10)));

    }
}

package lesson10;

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

public class CompareNumberMatcher<T extends Number> extends BaseMatcher<T> {

    private final T value;
    private final Boolean greater;

    public CompareNumberMatcher(T value, Boolean greater) {
        this.value = value;
        this.greater = greater;
    }

    @Factory
    public static <T extends Number> CompareNumberMatcher<T> gt(T value) {
        return new CompareNumberMatcher<>(value, true);
    }

    @Factory
    public static <T extends Number> CompareNumberMatcher<T> lt(T value) {
        return new CompareNumberMatcher<>(value, false);
    }

    @Override
    public boolean matches(Object actual) {
        Class<?> clazz = actual.getClass();
        if (clazz == Integer.class) {
            return greater ? (Integer) actual > (Integer) value : (Integer) actual < (Integer) value;
        } else if (clazz == Long.class) {
            return greater ? (Long) actual > (Long) value : (Long) actual < (Long) value;
        } else if (clazz == Short.class) {
            return greater ? (Short) actual > (Short) value : (Short) actual < (Short) value;
        } else if (clazz == Double.class) {
            return greater ? (Double) actual > (Double) value : (Double) actual < (Double) value;
        } else if (clazz == Float.class) {
            return greater ? (Float) actual > (Float) value : (Float) actual > (Float) value;
        } else if (clazz == Byte.class) {
            return greater ? (Byte) actual > (Byte) value : (Byte) actual < (Byte) value;
        } else {
            throw new AssertionError("The number type [" + clazz + "] not matched...");
        }
    }

    @Override
    public void describeTo(Description description) {
        description.appendText("compare value of two number");
    }
}