001package org.junit.internal;
002
003import java.lang.reflect.Array;
004import java.util.Arrays;
005
006import org.junit.Assert;
007
008/**
009 * Defines criteria for finding two items "equal enough". Concrete subclasses
010 * may demand exact equality, or, for example, equality within a given delta.
011 */
012public abstract class ComparisonCriteria {
013    /**
014     * Asserts that two arrays are equal, according to the criteria defined by
015     * the concrete subclass. If they are not, an {@link AssertionError} is
016     * thrown with the given message. If <code>expecteds</code> and
017     * <code>actuals</code> are <code>null</code>, they are considered equal.
018     *
019     * @param message the identifying message for the {@link AssertionError} (
020     * <code>null</code> okay)
021     * @param expecteds Object array or array of arrays (multi-dimensional array) with
022     * expected values.
023     * @param actuals Object array or array of arrays (multi-dimensional array) with
024     * actual values
025     */
026    public void arrayEquals(String message, Object expecteds, Object actuals)
027            throws ArrayComparisonFailure {
028        if (expecteds == actuals
029            || Arrays.deepEquals(new Object[] {expecteds}, new Object[] {actuals})) {
030            // The reflection-based loop below is potentially very slow, especially for primitive
031            // arrays. The deepEquals check allows us to circumvent it in the usual case where
032            // the arrays are exactly equal.
033            return;
034        }
035        String header = message == null ? "" : message + ": ";
036
037        int expectedsLength = assertArraysAreSameLength(expecteds,
038                actuals, header);
039
040        for (int i = 0; i < expectedsLength; i++) {
041            Object expected = Array.get(expecteds, i);
042            Object actual = Array.get(actuals, i);
043
044            if (isArray(expected) && isArray(actual)) {
045                try {
046                    arrayEquals(message, expected, actual);
047                } catch (ArrayComparisonFailure e) {
048                    e.addDimension(i);
049                    throw e;
050                }
051            } else {
052                try {
053                    assertElementsEqual(expected, actual);
054                } catch (AssertionError e) {
055                    throw new ArrayComparisonFailure(header, e, i);
056                }
057            }
058        }
059    }
060
061    private boolean isArray(Object expected) {
062        return expected != null && expected.getClass().isArray();
063    }
064
065    private int assertArraysAreSameLength(Object expecteds,
066            Object actuals, String header) {
067        if (expecteds == null) {
068            Assert.fail(header + "expected array was null");
069        }
070        if (actuals == null) {
071            Assert.fail(header + "actual array was null");
072        }
073        int actualsLength = Array.getLength(actuals);
074        int expectedsLength = Array.getLength(expecteds);
075        if (actualsLength != expectedsLength) {
076            Assert.fail(header + "array lengths differed, expected.length="
077                    + expectedsLength + " actual.length=" + actualsLength);
078        }
079        return expectedsLength;
080    }
081
082    protected abstract void assertElementsEqual(Object expected, Object actual);
083}