Java example source code file (ConstructorUtilsTest.java)

This example Java source code file (ConstructorUtilsTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

before, class, constructorutilstest, exception, hashmap, integer, map, nosuchmethodexception, object, privateclass, publicinnerclass, reflection, string, suppresswarnings, testbean, util

The ConstructorUtilsTest.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.lang3.reflect;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.lang.reflect.Constructor;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.apache.commons.lang3.mutable.MutableObject;
import org.junit.Before;
import org.junit.Test;

/**
 * Unit tests ConstructorUtils
 */
public class ConstructorUtilsTest {
    public static class TestBean {
        private final String toString;
        final String[] varArgs;

        public TestBean() {
            toString = "()";
            varArgs = null;
        }

        public TestBean(final int i) {
            toString = "(int)";
            varArgs = null;
        }

        public TestBean(final Integer i) {
            toString = "(Integer)";
            varArgs = null;
        }

        public TestBean(final double d) {
            toString = "(double)";
            varArgs = null;
        }

        public TestBean(final String s) {
            toString = "(String)";
            varArgs = null;
        }

        public TestBean(final Object o) {
            toString = "(Object)";
            varArgs = null;
        }

        public TestBean(final String... s) {
            toString = "(String...)";
            varArgs = s;
        }

        public TestBean(final Integer i, String... s) {
            toString = "(Integer, String...)";
            varArgs = s;
        }

        public TestBean(final Integer first, int... args) {
            toString = "(Integer, String...)";
            varArgs = new String[args.length];
            for(int i = 0; i< args.length; ++i) {
                varArgs[i] = Integer.toString(args[i]);
            }
        }

        @Override
        public String toString() {
            return toString;
        }

        void verify(final String str, final String[] args) {
          assertEquals(str, toString);
          assertArrayEquals(args, varArgs);
        }
    }

    private static class PrivateClass {
        @SuppressWarnings("unused")
        public PrivateClass() {
        }

        @SuppressWarnings("unused")
        public static class PublicInnerClass {
            public PublicInnerClass() {
            }
        }
    }

    private final Map<Class[]> classCache;

    public ConstructorUtilsTest() {
        classCache = new HashMap<Class[]>();
    }


    @Before
    public void setUp() throws Exception {
        classCache.clear();
    }

    @Test
    public void testConstructor() throws Exception {
        assertNotNull(MethodUtils.class.newInstance());
    }

    @Test
    public void testInvokeConstructor() throws Exception {
        assertEquals("()", ConstructorUtils.invokeConstructor(TestBean.class,
                (Object[]) ArrayUtils.EMPTY_CLASS_ARRAY).toString());
        assertEquals("()", ConstructorUtils.invokeConstructor(TestBean.class,
                (Object[]) null).toString());
        assertEquals("()", ConstructorUtils.invokeConstructor(TestBean.class).toString());
        assertEquals("(String)", ConstructorUtils.invokeConstructor(
                TestBean.class, "").toString());
        assertEquals("(Object)", ConstructorUtils.invokeConstructor(
                TestBean.class, new Object()).toString());
        assertEquals("(Object)", ConstructorUtils.invokeConstructor(
                TestBean.class, Boolean.TRUE).toString());
        assertEquals("(Integer)", ConstructorUtils.invokeConstructor(
                TestBean.class, NumberUtils.INTEGER_ONE).toString());
        assertEquals("(int)", ConstructorUtils.invokeConstructor(
                TestBean.class, NumberUtils.BYTE_ONE).toString());
        assertEquals("(double)", ConstructorUtils.invokeConstructor(
                TestBean.class, NumberUtils.LONG_ONE).toString());
        assertEquals("(double)", ConstructorUtils.invokeConstructor(
                TestBean.class, NumberUtils.DOUBLE_ONE).toString());
        ConstructorUtils.invokeConstructor(TestBean.class, NumberUtils.INTEGER_ONE)
          .verify("(Integer)", null);
        ConstructorUtils.invokeConstructor(TestBean.class, "a", "b")
          .verify("(String...)", new String[]{"a", "b"});
        ConstructorUtils.invokeConstructor(TestBean.class, NumberUtils.INTEGER_ONE, "a", "b")
          .verify("(Integer, String...)", new String[]{"a", "b"});
    }

    @Test
    public void testInvokeExactConstructor() throws Exception {
        assertEquals("()", ConstructorUtils.invokeExactConstructor(
                TestBean.class, (Object[]) ArrayUtils.EMPTY_CLASS_ARRAY).toString());
        assertEquals("()", ConstructorUtils.invokeExactConstructor(
                TestBean.class, (Object[]) null).toString());
        assertEquals("(String)", ConstructorUtils.invokeExactConstructor(
                TestBean.class, "").toString());
        assertEquals("(Object)", ConstructorUtils.invokeExactConstructor(
                TestBean.class, new Object()).toString());
        assertEquals("(Integer)", ConstructorUtils.invokeExactConstructor(
                TestBean.class, NumberUtils.INTEGER_ONE).toString());
        assertEquals("(double)", ConstructorUtils.invokeExactConstructor(
                TestBean.class, new Object[] { NumberUtils.DOUBLE_ONE },
                new Class[] { Double.TYPE }).toString());

        try {
            ConstructorUtils.invokeExactConstructor(TestBean.class,
                    NumberUtils.BYTE_ONE);
            fail("should throw NoSuchMethodException");
        } catch (final NoSuchMethodException e) {
        }
        try {
            ConstructorUtils.invokeExactConstructor(TestBean.class,
                    NumberUtils.LONG_ONE);
            fail("should throw NoSuchMethodException");
        } catch (final NoSuchMethodException e) {
        }
        try {
            ConstructorUtils.invokeExactConstructor(TestBean.class,
                    Boolean.TRUE);
            fail("should throw NoSuchMethodException");
        } catch (final NoSuchMethodException e) {
        }
    }

    @Test
    public void testGetAccessibleConstructor() throws Exception {
        assertNotNull(ConstructorUtils.getAccessibleConstructor(Object.class
                .getConstructor(ArrayUtils.EMPTY_CLASS_ARRAY)));
        assertNull(ConstructorUtils.getAccessibleConstructor(PrivateClass.class
                .getConstructor(ArrayUtils.EMPTY_CLASS_ARRAY)));
        assertNull(ConstructorUtils.getAccessibleConstructor(PrivateClass.PublicInnerClass.class));
    }

    @Test
    public void testGetAccessibleConstructorFromDescription() throws Exception {
        assertNotNull(ConstructorUtils.getAccessibleConstructor(Object.class,
                ArrayUtils.EMPTY_CLASS_ARRAY));
        assertNull(ConstructorUtils.getAccessibleConstructor(
                PrivateClass.class, ArrayUtils.EMPTY_CLASS_ARRAY));
    }

    @Test
    public void testGetMatchingAccessibleMethod() throws Exception {
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                ArrayUtils.EMPTY_CLASS_ARRAY, ArrayUtils.EMPTY_CLASS_ARRAY);
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class, null,
                ArrayUtils.EMPTY_CLASS_ARRAY);
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(String.class), singletonArray(String.class));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Object.class), singletonArray(Object.class));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Boolean.class), singletonArray(Object.class));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Byte.class), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Byte.TYPE), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Short.class), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Short.TYPE), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Character.class), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Character.TYPE), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Integer.class), singletonArray(Integer.class));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Integer.TYPE), singletonArray(Integer.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Long.class), singletonArray(Double.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Long.TYPE), singletonArray(Double.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Float.class), singletonArray(Double.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Float.TYPE), singletonArray(Double.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Double.class), singletonArray(Double.TYPE));
        expectMatchingAccessibleConstructorParameterTypes(TestBean.class,
                singletonArray(Double.TYPE), singletonArray(Double.TYPE));
    }

    @Test
    public void testNullArgument() {
        expectMatchingAccessibleConstructorParameterTypes(MutableObject.class,
                singletonArray(null), singletonArray(Object.class));
    }

    private void expectMatchingAccessibleConstructorParameterTypes(final Class<?> cls,
            final Class<?>[] requestTypes, final Class[] actualTypes) {
        final Constructor<?> c = ConstructorUtils.getMatchingAccessibleConstructor(cls,
                requestTypes);
        assertTrue(toString(c.getParameterTypes()) + " not equals "
                + toString(actualTypes), Arrays.equals(actualTypes, c
                .getParameterTypes()));
    }

    private String toString(final Class<?>[] c) {
        return Arrays.asList(c).toString();
    }

    private Class<?>[] singletonArray(final Class c) {
        Class<?>[] result = classCache.get(c);
        if (result == null) {
            result = new Class[] { c };
            classCache.put(c, result);
        }
        return result;
    }

    @Test
    public void testVarArgsUnboxing() throws Exception {
        TestBean testBean = ConstructorUtils.invokeConstructor(
                TestBean.class, Integer.valueOf(1), Integer.valueOf(2), Integer.valueOf(3));

        assertArrayEquals(new String[]{"2", "3"}, testBean.varArgs);
    }

}