NEW - bug 371010: [api] provide abstracted priority mapping

https://bugs.eclipse.org/bugs/show_bug.cgi?id=371010

Change-Id: I858678eac8c4803811553e18e65775244f61c78c

3 files changed, 149 insertions, 0 deletions

diff --git a/org.eclipse.mylyn.tasks.core/src/org/eclipse/mylyn/tasks/core/ITask.java b/org.eclipse.mylyn.tasks.core/src/org/eclipse/mylyn/tasks/core/ITask.java
index f3d77ea..6cf0129 100644
--- a/org.eclipse.mylyn.tasks.core/src/org/eclipse/mylyn/tasks/core/ITask.java
+++ b/org.eclipse.mylyn.tasks.core/src/org/eclipse/mylyn/tasks/core/ITask.java
@@ -13,6 +13,7 @@ package org.eclipse.mylyn.tasks.core;
 
 import java.util.Date;
 
+import org.eclipse.core.runtime.Assert;
 import org.eclipse.mylyn.internal.tasks.core.Messages;
 
 /**
@@ -72,11 +73,29 @@ public interface ITask extends IRepositoryElement, IAttributeContainer {
 	}
 
 	/**
+	 * Defines an interface for priorities that have an associated integer value.
+	 * 
+	 * @author Steffen Pingel
+	 * @since 3.7
+	 * @see PriorityLevel#fromValue(IPriorityValue[], IPriorityValue)
+	 */
+	public static interface IPriorityValue {
+
+		/**
+		 * Returns the integer value of this priority.
+		 */
+		int getPriorityValue();
+
+	}
+
+	/**
 	 * @since 3.0
 	 */
 	public enum PriorityLevel {
 		P1, P2, P3, P4, P5;
 
+		private static final int LEVEL_COUNT = PriorityLevel.values().length;
+
 		@Override
 		public String toString() {
 			switch (this) {
@@ -185,6 +204,34 @@ public interface ITask extends IRepositoryElement, IAttributeContainer {
 		}
 
 		/**
+		 * Maps a priority value to a {@link PriorityLevel}. The value needs to be present in <code>priorities</code>,
+		 * otherwise {@link PriorityLevel#getDefault()} is returned.
+		 * <p>
+		 * NOTE: <code>priorities</code> needs to be sorted in ascending order.
+		 * 
+		 * @param priorities
+		 *            a sorted array of priority levels
+		 * @param value
+		 *            the value to map
+		 * @since 3.7
+		 */
+		public static PriorityLevel fromValue(IPriorityValue[] priorities, IPriorityValue value) {
+			Assert.isNotNull(priorities);
+			if (value != null) {
+				int minValue = priorities[0].getPriorityValue();
+				int range = priorities[priorities.length - 1].getPriorityValue() - minValue;
+				for (IPriorityValue priority : priorities) {
+					if (value.equals(priority)) {
+						float relativeValue = (float) (priority.getPriorityValue() - minValue) / range;
+						int level = (int) (relativeValue * LEVEL_COUNT) + 1;
+						return PriorityLevel.fromLevel(level);
+					}
+				}
+			}
+			return PriorityLevel.getDefault();
+		}
+
+		/**
 		 * @since 3.0
 		 */
 		public static PriorityLevel getDefault() {
diff --git a/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/AllTasksTests.java b/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/AllTasksTests.java
index 7f36e08..abc4bd7 100644
--- a/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/AllTasksTests.java
+++ b/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/AllTasksTests.java
@@ -16,6 +16,7 @@ import junit.framework.TestSuite;
 
 import org.eclipse.mylyn.tasks.tests.core.FileTaskAttachmentSourceTest;
 import org.eclipse.mylyn.tasks.tests.core.ITasksCoreConstantsTest;
+import org.eclipse.mylyn.tasks.tests.core.PriorityLevelTest;
 import org.eclipse.mylyn.tasks.tests.core.TaskListUnmatchedContainerTest;
 import org.eclipse.mylyn.tasks.tests.core.TaskRepositoryLocationTest;
 import org.eclipse.mylyn.tasks.tests.data.TaskDataExternalizerTest;
@@ -118,6 +119,7 @@ public class AllTasksTests {
 		//suite.addTestSuite(BackgroundSaveTest.class);
 		suite.addTestSuite(MultipleTaskHyperlinkDetectorTest.class);
 		suite.addTestSuite(RegionComparatorTest.class);
+		suite.addTestSuite(PriorityLevelTest.class);
 		return suite;
 	}
 
diff --git a/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/core/PriorityLevelTest.java b/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/core/PriorityLevelTest.java
new file mode 100644
index 0000000..9b9213d
--- a/dev/null
+++ b/org.eclipse.mylyn.tasks.tests/src/org/eclipse/mylyn/tasks/tests/core/PriorityLevelTest.java
@@ -0,0 +1,100 @@
+/*******************************************************************************
+ * Copyright (c) 2012 Tasktop Technologies and others.
+ * 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:
+ *     Tasktop Technologies - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.mylyn.tasks.tests.core;
+
+import junit.framework.TestCase;
+
+import org.eclipse.mylyn.tasks.core.ITask.IPriorityValue;
+import org.eclipse.mylyn.tasks.core.ITask.PriorityLevel;
+
+/**
+ * @author Steffen Pingel
+ */
+public class PriorityLevelTest extends TestCase {
+
+	private static class Priority implements IPriorityValue {
+
+		private final int value;
+
+		public Priority(int value) {
+			this.value = value;
+		}
+
+		public int getPriorityValue() {
+			return value;
+		}
+
+		@Override
+		public int hashCode() {
+			final int prime = 31;
+			int result = 1;
+			result = prime * result + value;
+			return result;
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj == null) {
+				return false;
+			}
+			if (getClass() != obj.getClass()) {
+				return false;
+			}
+			Priority other = (Priority) obj;
+			if (value != other.value) {
+				return false;
+			}
+			return true;
+		}
+
+	}
+
+	public void testFromValueThreePriorities() {
+		Priority p1 = new Priority(1);
+		Priority p2 = new Priority(2);
+		Priority p3 = new Priority(3);
+		Priority[] priorities = new Priority[] { p1, p2, p3 };
+		assertEquals("P1", PriorityLevel.fromValue(priorities, new Priority(1)).toString());
+		assertEquals("P3", PriorityLevel.fromValue(priorities, new Priority(2)).toString());
+		assertEquals("P5", PriorityLevel.fromValue(priorities, new Priority(3)).toString());
+		assertEquals("P3", PriorityLevel.fromValue(priorities, new Priority(10)).toString());
+		assertEquals("P3", PriorityLevel.fromValue(priorities, null).toString());
+	}
+
+	public void testFromValueSinglePriority() {
+		Priority p1 = new Priority(10);
+		Priority[] priorities = new Priority[] { p1 };
+		assertEquals("P1", PriorityLevel.fromValue(priorities, new Priority(10)).toString());
+		assertEquals("P3", PriorityLevel.fromValue(priorities, new Priority(11)).toString());
+		assertEquals("P3", PriorityLevel.fromValue(priorities, null).toString());
+	}
+
+	public void testFromValueSixPriorites() {
+		Priority p1 = new Priority(10);
+		Priority p2 = new Priority(20);
+		Priority p3 = new Priority(30);
+		Priority p4 = new Priority(40);
+		Priority p5 = new Priority(70);
+		Priority p6 = new Priority(100);
+		Priority[] priorities = new Priority[] { p1, p2, p3, p4, p5, p6 };
+		assertEquals("P1", PriorityLevel.fromValue(priorities, new Priority(10)).toString());
+		assertEquals("P1", PriorityLevel.fromValue(priorities, new Priority(20)).toString());
+		assertEquals("P2", PriorityLevel.fromValue(priorities, new Priority(30)).toString());
+		assertEquals("P2", PriorityLevel.fromValue(priorities, new Priority(40)).toString());
+		assertEquals("P4", PriorityLevel.fromValue(priorities, new Priority(70)).toString());
+		assertEquals("P5", PriorityLevel.fromValue(priorities, new Priority(100)).toString());
+	}
+
+}