common/tests/org.eclipse.jpt.common.utility.tests/src/org/eclipse/jpt/common/utility/tests/internal/comparator/ReverseComparatorTests.java

/*******************************************************************************
 * Copyright (c) 2005, 2013 Oracle. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0, which accompanies this distribution
 * and is available at http://www.eclipse.org/legal/epl-v10.html.
 * 
 * Contributors:
 *     Oracle - initial API and implementation
 ******************************************************************************/
package org.eclipse.jpt.common.utility.tests.internal.comparator;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import junit.framework.TestCase;
import org.eclipse.jpt.common.utility.internal.ObjectTools;
import org.eclipse.jpt.common.utility.internal.comparator.ReverseComparator;
import org.eclipse.jpt.common.utility.tests.internal.TestTools;

@SuppressWarnings("nls")
public class ReverseComparatorTests
	extends TestCase
{
	private Comparator<String> naturalReverseComparator;
	private Comparator<String> customComparator;
	private Comparator<String> customReverseComparator;

	public ReverseComparatorTests(String name) {
		super(name);
	}

	@Override
	protected void setUp() throws Exception {
		super.setUp();
		this.naturalReverseComparator = new ReverseComparator<String>();
		this.customComparator = this.buildCustomComparator();
		this.customReverseComparator = new ReverseComparator<String>(this.customComparator);
	}

	private Comparator<String> buildCustomComparator() {
		return new Comparator<String>() {
			public int compare(String s1, String s2) {
				String lower1 = s1.toLowerCase();
				String lower2 = s2.toLowerCase();
				int result = lower1.compareTo(lower2);
				if (result == 0) {
					return s1.compareTo(s2); // use case to differentiate "equal" strings
				}
				return result;
			}
		};
	}

	private List<String> buildUnsortedList() {
		List<String> result = new ArrayList<String>();
		result.add("T");
		result.add("Z");
		result.add("Y");
		result.add("M");
		result.add("m");
		result.add("a");
		result.add("B");
		result.add("b");
		result.add("A");
		return result;
	}

	private List<String> buildNaturallySortedList() {
		List<String> result = new ArrayList<String>(this.buildUnsortedList());
		Collections.sort(result);
		return result;
	}

	private List<String> buildCustomSortedList() {
		List<String> result = new ArrayList<String>(this.buildUnsortedList());
		Collections.sort(result, this.customComparator);
		return result;
	}

	@Override
	protected void tearDown() throws Exception {
		TestTools.clear(this);
		super.tearDown();
	}

	public void testNatural() {
		List<String> list = this.buildUnsortedList();
		Collections.sort(list, this.naturalReverseComparator);
		this.verifyList(this.buildNaturallySortedList(), list);
	}

	public void testCustom() {
		List<String> list = this.buildUnsortedList();
		Collections.sort(list, this.customReverseComparator);
		this.verifyList(this.buildCustomSortedList(), list);
	}

	public void testCustom_nonComparable() {
		List<Foo> list = this.buildUnsortedFooList();
		Collections.sort(list, new ReverseComparator<Foo>(Foo.COMPARATOR));
		this.verifyList(this.buildSortedFooList(), list);
	}

	private List<Foo> buildUnsortedFooList() {
		List<Foo> result = new ArrayList<Foo>();
		result.add(new Foo("T"));
		result.add(new Foo("Z"));
		result.add(new Foo("Y"));
		result.add(new Foo("M"));
		result.add(new Foo("m"));
		result.add(new Foo("a"));
		result.add(new Foo("B"));
		result.add(new Foo("b"));
		result.add(new Foo("A"));
		return result;
	}

	private List<Foo> buildSortedFooList() {
		List<Foo> result = new ArrayList<Foo>(this.buildUnsortedFooList());
		Collections.sort(result, Foo.COMPARATOR);
		return result;
	}

	private <T> void verifyList(List<T> normal, List<T> reverse) {
		int size = normal.size();
		int max = size - 1;
		for (int i = 0; i < size; i++) {
			assertEquals(normal.get(i), reverse.get(max - i));
		}
	}

	public static class Foo {
		public final String string;
		public Foo(String string) {
			super();
			this.string = string;
		}
		@Override
		public boolean equals(Object o) {
			return (o instanceof Foo) && this.string.equals(((Foo) o).string);
		}
		@Override
		public int hashCode() {
			return this.string.hashCode();
		}
		@Override
		public String toString() {
			return ObjectTools.toString(this, this.string);
		}
		public static final Comparator<Foo> COMPARATOR = new FooComparator();
		public static class FooComparator
			implements Comparator<Foo>
		{
			public int compare(Foo foo1, Foo foo2) {
				String s1 = foo1.string;
				String s2 = foo2.string;
				String lower1 = s1.toLowerCase();
				String lower2 = s2.toLowerCase();
				int result = lower1.compareTo(lower2);
				if (result == 0) {
					return s1.compareTo(s2); // use case to differentiate "equal" strings
				}
				return result;
			}
			@Override
			public String toString() {
				return ObjectTools.singletonToString(this);
			}
		}
	}
}