de.codecentric.mule.assertobjectequals.ObjectComparator Maven / Gradle / Ivy

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package de.codecentric.mule.assertobjectequals;

import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Compare two objects, drill down into List an
 */
public class ObjectComparator {
    private ObjectCompareOptionsFactory optionFactory;

    private class State {
        final Path path;
        final Object expected;
        final Object actual;
        final EnumSet options;

        private State(Path path, Object expected, Object actual, EnumSet options) {
            this.path = path;
            this.expected = expected;
            this.actual = actual;
            this.options = options;
        }

        public State(Object expected, Object actual) {
            path = new Path();
            this.expected = expected;
            this.actual = actual;
            options = optionFactory.createOptions(null, path);
        }

        public State listEntry(int listIndex, int listSize, Object expected, Object actual) {
            Path next = path.listEntry(listIndex, listSize);
            return new State(next, expected, actual, optionFactory.createOptions(options, next));
        }

        public State mapEntry(String key, Object expected, Object actual) {
            Path next = path.mapEntry(key);
            return new State(next, expected, actual, optionFactory.createOptions(options, next));
        }
    }

    public ObjectComparator(ObjectCompareOptionsFactory optionFactory) {
        this.optionFactory = optionFactory;
    }

    /**
     * Compare two objects. Drill down into {@link Map} and {@link List}, use {@link Object#equals(Object)} for all
     * other classes.
     *
     * @param expected
     *            The expected value.
     * @param actual
     *            The actual value.
     * @return Textual description of the differences.
     */
    public Collection compare(Object expected, Object actual) {
        State state = new State(expected, actual);
        Collection diffs = new ArrayList();
        compare(state, diffs);
        return diffs;
    }

    private void compare(State state, Collection diffs) {
        if (state.options.contains(PathOption.IGNORE)) {
            return;
        }
        if (state.expected == null) {
            if (state.actual == null) {
                // ok, null equals null
            } else { // actual != null
                diffs.add("at '" + state.path + "', expected is null, actual " + state.actual);
            }
        } else { // expected != null
            if (state.actual == null) {
                diffs.add("at '" + state.path + "', expected " + state.expected + ", actual is null");
            } else { // actual != null
                compareNonNullObjects(state, diffs);
            }
        }
    }

    private void compareNonNullObjects(State state, Collection diffs) {
        if (state.expected instanceof List) {
            if (state.actual instanceof List) {
                compareLists(state, diffs);
            } else {
                diffs.add("at '" + state.path + "', expected List, but found " + state.actual.getClass().getName());
            }
        } else if (state.expected instanceof Map) {
            if (state.actual instanceof Map) {
                compareMaps(state, diffs);
            }
        } else {
            if (!state.expected.equals(state.actual)) {
                diffs.add("at '" + state.path + "', expected " + state.expected + ", but found " + state.actual);
            }
        }
    }

    private void compareLists(State state, Collection diffs) {
        @SuppressWarnings("unchecked")
        List