gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/traversal/util/DefaultTraversalStrategiesTest.java

/*
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 * 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
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package org.apache.tinkerpop.gremlin.process.traversal.util;

import org.apache.tinkerpop.gremlin.process.TraversalStrategiesTest;
import org.apache.tinkerpop.gremlin.process.traversal.Operator;
import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategies;
import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy;
import org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration.SideEffectStrategy;
import org.junit.Test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

/**
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 */
public class DefaultTraversalStrategiesTest {

    TraversalStrategy
            a = new TraversalStrategiesTest.StrategyA(),
            b = new TraversalStrategiesTest.StrategyB(),
            c = new TraversalStrategiesTest.StrategyC(),
            d = new TraversalStrategiesTest.StrategyD(),
            e = new TraversalStrategiesTest.StrategyE(),
            k = new TraversalStrategiesTest.StrategyK(),
            l = new TraversalStrategiesTest.StrategyL(),
            m = new TraversalStrategiesTest.StrategyM(),
            n = new TraversalStrategiesTest.StrategyN(),
            o = new TraversalStrategiesTest.StrategyO();

    @Test
    public void testNoRepeatStrategies() {
        final TraversalStrategies s = new DefaultTraversalStrategies();
        s.addStrategies(b, a, d, b, a, a, d, d);
        s.addStrategies(new TraversalStrategiesTest.StrategyD(), new TraversalStrategiesTest.StrategyB());
        assertEquals(3, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(d, s.toList().get(2));
    }

    @Test
    public void testWellDefinedDependency() {
        //Dependency well defined
        final TraversalStrategies s = new DefaultTraversalStrategies();
        s.addStrategies(b, a);
        assertEquals(2, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
    }

    @Test
    public void testNoDependency() {
        //No dependency
        final TraversalStrategies s = new DefaultTraversalStrategies();
        s.addStrategies(c, a);
        assertEquals(2, s.toList().size());
    }

    @Test
    public void testWellDefinedDependency2() {
        //Dependency well defined
        TraversalStrategies s = new DefaultTraversalStrategies();
        s.addStrategies(c, a, b);
        assertEquals(3, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(c, s.toList().get(2));
        s = s.clone();
        assertEquals(3, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(c, s.toList().get(2));
    }

    @Test
    public void testCircularDependency() {
        //Circular dependency => throws exception
        final TraversalStrategies s = new DefaultTraversalStrategies();
        try {
            s.addStrategies(c, k, a, b);
            fail();
        } catch (IllegalStateException ex) {
            assertTrue(ex.getMessage().toLowerCase().contains("cyclic"));
        }
    }

    @Test
    public void testWellDefinedDependency3() {
        //Dependency well defined
        TraversalStrategies s = new DefaultTraversalStrategies();
        s.addStrategies(d, c, a, e, b);
        assertEquals(5, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(d, s.toList().get(2));
        assertEquals(c, s.toList().get(3));
        assertEquals(e, s.toList().get(4));
        s = s.clone();
        assertEquals(5, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(d, s.toList().get(2));
        assertEquals(c, s.toList().get(3));
        assertEquals(e, s.toList().get(4));
    }

    @Test
    public void testCircularDependency2() {
        //Circular dependency => throws exception
        final TraversalStrategies s = new DefaultTraversalStrategies();
        try {
            s.addStrategies(d, c, k, a, e, b);
            fail();
        } catch (IllegalStateException ex) {
            assertTrue(ex.getMessage().toLowerCase().contains("cyclic"));
        }
    }

    @Test
    public void testLotsOfStrategies() {
        //Lots of strategies
        TraversalStrategies s = new DefaultTraversalStrategies();
        s = s.addStrategies(b, l, m, n, o, a);
        assertTrue(s.toList().indexOf(a) < s.toList().indexOf(b));
        s = s.clone();
        assertTrue(s.toList().indexOf(a) < s.toList().indexOf(b));

        // sort and then add more
        s = new DefaultTraversalStrategies();
        s.addStrategies(b, a, c);
        assertEquals(3, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(c, s.toList().get(2));
        s.addStrategies(d);
        s = s.clone();
        assertEquals(4, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(d, s.toList().get(2));
        assertEquals(c, s.toList().get(3));
        s.addStrategies(e);
        assertEquals(5, s.toList().size());
        assertEquals(a, s.toList().get(0));
        assertEquals(b, s.toList().get(1));
        assertEquals(d, s.toList().get(2));
        assertEquals(c, s.toList().get(3));
        assertEquals(e, s.toList().get(4));
    }

    @Test
    public void testCloningAndStatefulStrategies() {
        final DefaultTraversal firstTraversal = new DefaultTraversal();
        final DefaultTraversalStrategies first = new DefaultTraversalStrategies();
        assertEquals(0, first.traversalStrategies.size());
        SideEffectStrategy.addSideEffect(first, "a", 2, Operator.sum);
        assertEquals(1, first.traversalStrategies.size());
        firstTraversal.setStrategies(first);
        firstTraversal.applyStrategies();
        assertEquals(1, firstTraversal.getSideEffects().keys().size());
        assertEquals(2, firstTraversal.getSideEffects().<Integer>get("a").intValue());
        final DefaultTraversalStrategies second = first.clone();
        SideEffectStrategy.addSideEffect(second, "b", "marko", Operator.assign);

        final DefaultTraversal secondTraversal = new DefaultTraversal();
        secondTraversal.setStrategies(first);
        secondTraversal.applyStrategies();
        assertEquals(1, secondTraversal.getSideEffects().keys().size());
        assertEquals(2, secondTraversal.getSideEffects().<Integer>get("a").intValue());

        final DefaultTraversal thirdTraversal = new DefaultTraversal();
        thirdTraversal.setStrategies(second);
        thirdTraversal.applyStrategies();
        assertEquals(2, thirdTraversal.getSideEffects().keys().size());
        assertEquals(2, thirdTraversal.getSideEffects().<Integer>get("a").intValue());
        assertEquals("marko", thirdTraversal.getSideEffects().get("b"));

        SideEffectStrategy.addSideEffect(second, "c", "hello", Operator.assign);
        final DefaultTraversal forthTraversal = new DefaultTraversal();
        forthTraversal.setStrategies(second);
        forthTraversal.applyStrategies();
        assertEquals(3, forthTraversal.getSideEffects().keys().size());
        assertEquals(2, forthTraversal.getSideEffects().<Integer>get("a").intValue());
        assertEquals("marko", forthTraversal.getSideEffects().get("b"));
        assertEquals("hello", forthTraversal.getSideEffects().get("c"));

        final DefaultTraversal fifthTraversal = new DefaultTraversal();
        fifthTraversal.setStrategies(first);
        fifthTraversal.applyStrategies();
        assertEquals(1, fifthTraversal.getSideEffects().keys().size());
        assertEquals(2, fifthTraversal.getSideEffects().<Integer>get("a").intValue());

        assertSame(firstTraversal.getStrategies(), secondTraversal.getStrategies());
        assertNotSame(firstTraversal.getStrategies(), thirdTraversal.getStrategies());
        assertSame(forthTraversal.getStrategies(), thirdTraversal.getStrategies());
        assertSame(fifthTraversal.getStrategies(), firstTraversal.getStrategies());
    }
}