src/test/java/org/apache/commons/configuration2/convert/TestDefaultConversionHandler.java

/*
 * 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.configuration2.convert;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collection;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.configuration2.ex.ConversionException;
import org.apache.commons.configuration2.interpol.ConfigurationInterpolator;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

/**
 * Test class for {@code DefaultConversionHandler}.
 *
 */
public class TestDefaultConversionHandler
{
    /** Constant for a variable. */
    private static final String VAR = "${test}";

    /** Constant for the value to replace the variable. */
    private static final String REPLACEMENT = "1";

    /** The conversion handler to be tested. */
    private DefaultConversionHandler handler;

    @Before
    public void setUp() throws Exception
    {
        handler = new DefaultConversionHandler();
    }

    /**
     * Creates a special test ConfigurationInterpolator. This object only
     * replaces the test variable by its replacement. Other substitutions are
     * not performed.
     *
     * @return the test {@code ConfigurationInterpolator}
     */
    private static ConfigurationInterpolator createInterpolator()
    {
        return new ConfigurationInterpolator()
        {
            @Override
            public Object interpolate(final Object value)
            {
                if (VAR.equals(value))
                {
                    return REPLACEMENT;
                }
                return value;
            }
        };
    }

    /**
     * Helper method for testing the result of the conversion of a single value.
     *
     * @param expResult the expected result
     */
    private void checkSingleValue(final Integer expResult)
    {
        assertEquals("Wrong result", Integer.parseInt(REPLACEMENT),
                expResult.intValue());
    }

    /**
     * Tests a conversion with a ConfigurationInterpolator.
     */
    @Test
    public void testToWithInterpolator()
    {
        final Integer result = handler.to(VAR, Integer.class, createInterpolator());
        checkSingleValue(result);
    }

    /**
     * Tests whether a ConfigurationInterpolator is optional.
     */
    @Test
    public void testToNoInterpolator()
    {
        final Integer result = handler.to(REPLACEMENT, Integer.class, null);
        checkSingleValue(result);
    }

    /**
     * Tests a failed conversion.
     */
    @Test(expected = ConversionException.class)
    public void testToFailedConversion()
    {
        handler.to(VAR, Integer.class, null);
    }

    /**
     * Tests whether a conversion from an array is possible.
     */
    @Test
    public void testToFromArray()
    {
        final Object[] src = {
                VAR, true, 20130808221759L
        };
        checkSingleValue(handler.to(src, Integer.class, createInterpolator()));
    }

    /**
     * Tests whether a conversion from a collection is possible.
     */
    @Test
    public void testToFromCollection()
    {
        final Collection<String> src = Arrays.asList(VAR, "true", "1000");
        checkSingleValue(handler.to(src, Integer.class, createInterpolator()));
    }

    /**
     * Tests whether a conversion from an iterator is possible.
     */
    @Test
    public void testToFromIterator()
    {
        final Iterator<String> src = Arrays.asList(VAR, "true", "1000").iterator();
        checkSingleValue(handler.to(src, Integer.class, createInterpolator()));
    }

    /**
     * Tests whether empty complex objects are handled when converting to a
     * single value.
     */
    @Test
    public void testToFromEmptyCollection()
    {
        assertNull("Wrong result", handler.to(new ArrayList<>(),
                Integer.class, createInterpolator()));
    }

    /**
     * Tests whether null input is handled by to().
     */
    @Test
    public void testToNull()
    {
        assertNull("Wrong result", handler.to(null, Integer.class, null));
    }

    /**
     * Tests a conversion to a collection if the source object is null.
     */
    @Test
    public void testToCollectionNullInput()
    {
        final ArrayList<Integer> col = new ArrayList<>();
        handler.toCollection(null, Integer.class, null, col);
        assertTrue("Got elements", col.isEmpty());
    }

    /**
     * Tries to pass a null collection to toCollection().
     */
    @Test(expected = IllegalArgumentException.class)
    public void testToCollectionNullCollection()
    {
        handler.toCollection(Arrays.asList(1, 2, 3), Integer.class, null, null);
    }

    /**
     * Tests a successful conversion to a collection.
     */
    @Test
    public void testToCollectionSuccess()
    {
        final Object[] src = {
                VAR, "100"
        };
        final List<Integer> col = new ArrayList<>(src.length);
        handler.toCollection(src, Integer.class, createInterpolator(), col);
        assertEquals("Wrong number of elements", src.length, col.size());
        assertEquals("Wrong element (1)", Integer.parseInt(REPLACEMENT), col
                .get(0).intValue());
        assertEquals("Wrong element (2)", Integer.parseInt(src[1].toString()),
                col.get(1).intValue());
    }

    /**
     * Tests a conversion to a collection if an empty string is passed in. An
     * empty string should be interpreted as a list with no values.
     */
    @Test
    public void testToCollectionEmptyString()
    {
        final List<Integer> col = new ArrayList<>(1);
        handler.toCollection("", Integer.class, null, col);
        assertTrue("Got elements", col.isEmpty());
    }

    /**
     * Tests toArray() if the source object is null.
     */
    @Test
    public void testToArrayNullInput()
    {
        assertNull("Wrong result", handler.toArray(null, Integer.class, null));
    }

    /**
     * Tests a conversion to an array of Objects.
     */
    @Test
    public void testToArrayObject()
    {
        final List<String> src = Arrays.asList(VAR, "100");
        final Integer[] array =
                (Integer[]) handler.toArray(src, Integer.class,
                        createInterpolator());
        assertEquals("Wrong number of elements", src.size(), array.length);
        assertEquals("Wrong element (1)", Integer.valueOf(REPLACEMENT),
                array[0]);
        assertEquals("Wrong element (2)", Integer.valueOf(src.get(1)), array[1]);
    }

    /**
     * Tests a conversion to an array of primitive type if the source array
     * already has the correct type.
     */
    @Test
    public void testToArrayPrimitiveSameType()
    {
        final int[] src = {
                1, 2, 3, 4, 5, 6
        };
        final int[] array =
                (int[]) handler
                        .toArray(src, Integer.TYPE, createInterpolator());
        Assert.assertArrayEquals("Wrong array result", src, array);
    }

    /**
     * Tests a conversion to an array of primitive type if the source array is
     * of the corresponding wrapper type.
     */
    @Test
    public void testToArrayPrimitiveWrapperType()
    {
        final Integer[] src = {
                0, 1, 2, 4, 8, 16, 32, 64, 128
        };
        final int[] array =
                (int[]) handler
                        .toArray(src, Integer.TYPE, createInterpolator());
        assertEquals("Wrong array length", src.length, array.length);
        for (int i = 0; i < src.length; i++)
        {
            assertEquals("Wrong element at " + i, src[i].intValue(), array[i]);
        }
    }

    /**
     * Tests a conversion to an array of primitive type if the source object is
     * something else.
     */
    @Test
    public void testToArrayPrimitiveOtherType()
    {
        final List<String> src = Arrays.asList(VAR, "100");
        final int[] array =
                (int[]) handler
                        .toArray(src, Integer.TYPE, createInterpolator());
        assertEquals("Wrong element (1)", Integer.parseInt(REPLACEMENT),
                array[0]);
        assertEquals("Wrong element (2)", Integer.parseInt(src.get(1)),
                array[1]);
    }

    /**
     * Tests a conversion to an array from an empty string. An empty string
     * should be interpreted as an empty array.
     */
    @Test
    public void testToArrayEmptyString()
    {
        final int[] array = (int[]) handler.toArray("", Integer.TYPE, null);
        assertEquals("Got elements", 0, array.length);
    }

    /**
     * Tests whether the default date format is used if no format has been set.
     */
    @Test
    public void testGetDateFormatNotSet()
    {
        assertEquals("Wrong date format",
                DefaultConversionHandler.DEFAULT_DATE_FORMAT,
                handler.getDateFormat());
    }

    /**
     * Tests whether the date format can be changed.
     */
    @Test
    public void testSetDateFormat()
    {
        final String dateFormat = "dd.MM.yyyy";
        handler.setDateFormat(dateFormat);
        assertEquals("Date format not changed", dateFormat,
                handler.getDateFormat());
    }

    /**
     * Tests whether a conversion to a date object is possible if a specific
     * date format is used.
     */
    @Test
    public void testToDateWithFormat()
    {
        handler.setDateFormat("dd.MM.yyyy");
        final Date dt = handler.to("19.08.2013", Date.class, null);
        final Calendar cal = Calendar.getInstance();
        cal.setTime(dt);
        assertEquals("Wrong day", 19, cal.get(Calendar.DATE));
        assertEquals("Wrong month", Calendar.AUGUST, cal.get(Calendar.MONTH));
        assertEquals("Wrong year", 2013, cal.get(Calendar.YEAR));
    }

    /**
     * Tests a conversion to a Calendar object using the default format.
     */
    @Test
    public void testToCalendarWithDefaultFormat()
    {
        final Calendar cal = handler.to("2013-08-19 21:17:22", Calendar.class, null);
        assertEquals("Wrong day", 19, cal.get(Calendar.DATE));
        assertEquals("Wrong month", Calendar.AUGUST, cal.get(Calendar.MONTH));
        assertEquals("Wrong year", 2013, cal.get(Calendar.YEAR));
        assertEquals("Wrong hour", 21, cal.get(Calendar.HOUR_OF_DAY));
        assertEquals("Wrong minute", 17, cal.get(Calendar.MINUTE));
        assertEquals("Wrong second", 22, cal.get(Calendar.SECOND));
    }

    /**
     * Tests a conversion to a primitive type.
     */
    @Test
    public void testToPrimitive()
    {
        final Long value = 20130819214935L;
        final Object result = handler.to(value.toString(), Long.TYPE, null);
        assertEquals("Wrong conversion result", value, result);
    }
}