DATACMNS-303 - Added support for count projects in query parsing.

PartTree now supports query methods starting with "count…By" and exposes that fact through an isCountProjection() method to be used by query creators upstream

src/main/java/org/springframework/data/repository/query/parser/PartTree.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,7 +37,7 @@ import org.springframework.util.StringUtils;
  */
 public class PartTree implements Iterable<OrPart> {
 
-	private static final Pattern PREFIX_TEMPLATE = Pattern.compile("^(find|read|get)(\\p{Lu}.*?)??By");
+	private static final Pattern PREFIX_TEMPLATE = Pattern.compile("^(find|read|get|count)(\\p{Lu}.*?)??By");
 	private static final String KEYWORD_TEMPLATE = "(%s)(?=\\p{Lu})";
 
 	/**
@@ -67,7 +67,7 @@ public class PartTree implements Iterable<OrPart> {
 			this.subject = new Subject(null);
 			this.predicate = new Predicate(source, domainClass);
 		} else {
-			this.subject = new Subject(matcher.group(2));
+			this.subject = new Subject(matcher.group(0));
 			this.predicate = new Predicate(source.substring(matcher.group().length()), domainClass);
 		}
 	}
@@ -94,13 +94,21 @@ public class PartTree implements Iterable<OrPart> {
 	/**
 	 * Returns whether we indicate distinct lookup of entities.
 	 * 
-	 * @return <tt>true<tt> if distinct
+	 * @return {@literal true} if distinct
 	 */
 	public boolean isDistinct() {
-
 		return subject.isDistinct();
 	}
 
+	/**
+	 * Returns whether a count projection shall be applied.
+	 * 
+	 * @return
+	 */
+	public Boolean isCountProjection() {
+		return subject.isCountProjection();
+	}
+
 	/**
 	 * Returns an {@link Iterable} of all parts contained in the {@link PartTree}.
 	 * 
@@ -141,7 +149,7 @@ public class PartTree implements Iterable<OrPart> {
 
 		OrderBySource orderBySource = predicate.getOrderBySource();
 		return String.format("%s%s", StringUtils.collectionToDelimitedString(predicate.nodes, " or "),
-				(orderBySource == null ? "" : " " + orderBySource));
+				orderBySource == null ? "" : " " + orderBySource);
 	}
 
 	/**
@@ -198,15 +206,24 @@ public class PartTree implements Iterable<OrPart> {
 	 * {@code DistinctUser}.
 	 * 
 	 * @author Phil Webb
+	 * @author Oliver Gierke
 	 */
 	private static class Subject {
 
 		private static final String DISTINCT = "Distinct";
+		private static final Pattern COUNT_BY_TEMPLATE = Pattern.compile("^count(\\p{Lu}.*?)??By");
 
-		private boolean distinct;
+		private final boolean distinct;
+		private final boolean count;
 
 		public Subject(String subject) {
-			this.distinct = (subject == null ? false : subject.contains(DISTINCT));
+
+			this.distinct = subject == null ? false : subject.contains(DISTINCT);
+			this.count = subject == null ? false : COUNT_BY_TEMPLATE.matcher(subject).find();
+		}
+
+		public boolean isCountProjection() {
+			return count;
 		}
 
 		public boolean isDistinct() {
@@ -269,4 +286,5 @@ public class PartTree implements Iterable<OrPart> {
 			return orderBySource;
 		}
 	}
+
 }

src/test/java/org/springframework/data/repository/query/parser/PartTreeUnitTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2010 the original author or authors.
+ * Copyright 2008-2013 the original author or authors.
  *
  * 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
@@ -318,6 +318,37 @@ public class PartTreeUnitTests {
 		assertTrue(tree.getSort().getOrderFor("år").isAscending());
 	}
 
+	/**
+	 * @see DATACMNS-303
+	 */
+	@Test
+	public void identifiesSimpleCountByCorrectly() {
+
+		PartTree tree = new PartTree("countByLastname", User.class);
+		assertThat(tree.isCountProjection(), is(true));
+	}
+
+	/**
+	 * @see DATACMNS-303
+	 */
+	@Test
+	public void identifiesExtendedCountByCorrectly() {
+
+		PartTree tree = new PartTree("countUserByLastname", User.class);
+		assertThat(tree.isCountProjection(), is(true));
+	}
+
+	/**
+	 * @see DATACMNS-303
+	 */
+	@Test
+	public void identifiesCountAndDistinctByCorrectly() {
+
+		PartTree tree = new PartTree("countDistinctUserByLastname", User.class);
+		assertThat(tree.isCountProjection(), is(true));
+		assertThat(tree.isDistinct(), is(true));
+	}
+
 	private static void assertType(Iterable<String> sources, Type type, String property) {
 		assertType(sources, type, property, 1, true);
 	}