MetaModelTestCase.java

/*
 * Copyright 2013 eXo Platform SAS
 *
 * Licensed 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 juzu.impl.metamodel;

import juzu.impl.common.CycleDetectionException;
import juzu.test.AbstractTestCase;
import org.junit.Test;

import java.util.Arrays;
import java.util.LinkedList;

/** @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a> */
public class MetaModelTestCase extends AbstractTestCase {
  
  /** . */
  private static final Key<MetaModelObject> A = Key.of("a", MetaModelObject.class);

  /** . */
  private static final Key<MetaModelObject> B = Key.of("b", MetaModelObject.class);

  /** . */
  private static final Key<MetaModelObject> C = Key.of("c", MetaModelObject.class);

  /** . */
  private static final Key<MetaModelObject> D = Key.of("d", MetaModelObject.class);

  /** . */
  private Context context;

  @Override
  public void setUp() throws Exception {
    this.context = new Context();
  }

  @Test
  public void testCannotRemoveRoot() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    a.addChild(B, b);

    //
    a.remove();
    assertSame(b, a.getChild(B));
    context.assertEmpty();
  }

  @Test
  public void testTransitiveRemove() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    Simple c = context.create("c");
    a.addChild(B, b).addChild(C, c);

    //
    b.remove();
    context.assertPreDetach("c");
    context.assertRemove("c");
    context.assertPreDetach("b");
    context.assertRemove("b");
    context.assertEmpty();
  }

  @Test
  public void testTransitiveRemoveChild() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    Simple c = context.create("c");
    a.addChild(B, b).addChild(C, c);

    //
    a.removeChild(B);
    context.assertPreDetach("c");
    context.assertRemove("c");
    context.assertPreDetach("b");
    context.assertRemove("b");
    context.assertEmpty();
  }

  @Test
  public void testRemoveOrphan() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    Simple c = context.create("c");
    a.addChild(C, c);
    b.addChild(C, c);

    //
    a.removeChild(C);
    context.assertPreDetach("c");
    context.assertEmpty();
    b.removeChild(C);
    context.assertPreDetach("c");
    context.assertRemove("c");
    context.assertEmpty();
  }

  @Test
  public void testBug() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    Simple c = context.create("c");
    Simple d = context.create("d");
    a.addChild(C, c);
    b.addChild(C, c);
    c.addChild(D, d);

    //
    assertSame(c, a.removeChild(C));
    assertNull(a.getChild(C));
    assertSame(c, b.getChild(C));
    assertSame(d, c.getChild(D));
  }

  @Test
  public void testEventWhenRemoved() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    a.addChild(B, b);

  }

  @Test
  public void testCycleDetection() {
    Simple a = context.create("a");
    Simple b = context.create("b");
    Simple c = context.create("c");
    a.addChild(B, b);
    b.addChild(C, c);
    try {
      c.addChild(A, a);
      fail("Was expecting cycle detection");
    }
    catch (CycleDetectionException ok) {
      assertEquals(Arrays.asList(a, b, c), ok.getPath());
    }
  }

  @Test
  public void testSelfCycleDetection() {
    Simple a = context.create("a");
    try {
      a.addChild(A, a);
      fail("Was expecting cycle detection");
    }
    catch (CycleDetectionException ok) {
      assertEquals(Arrays.asList(a), ok.getPath());
    }
  }

  static class Simple extends MetaModelObject {

    /** . */
    final Context context;
    
    /** . */
    final String name;

    Simple(Context context, String name) {
      this.context = context;
      this.name = name;
    }

    @Override
    protected void preDetach(MetaModelObject parent) {
      context.addLast(new Event(this, Event.PRE_DETACH));
    }

    @Override
    protected void preRemove() {
      context.addLast(new Event(this, Event.REMOVED));
    }

    @Override
    public String toString() {
      return "Simple[" + name + "]";
    }
  }
  
  static class Event {

    /** . */
    static final int ADDED = 0;

    /** . */
    static final int REMOVED = 1;

    /** . */
    static final int PRE_DETACH = 2;

    /** . */
    private final Simple source;

    /** . */
    private final int kind;

    Event(Simple source, int kind) {
      this.source = source;
      this.kind = kind;
    }
  }

  static class Context extends LinkedList<Event> {

    Simple create(String name) {
      return new Simple(this, name);
    }

    void assertRemove(String name) {
      assertTrue("Expecting to have at least one event", size() > 0);
      Event event = removeFirst();
      assertEquals(Event.REMOVED, event.kind);
      assertEquals(name, event.source.name);
    }

    void assertPreDetach(String name) {
      assertTrue("Expecting to have at least one event", size() > 0);
      Event event = removeFirst();
      assertEquals(Event.PRE_DETACH, event.kind);
      assertEquals(name, event.source.name);
    }

    void assertEmpty() {
      assertTrue(isEmpty());
    }
  }
}