Add support for @GrabExclude to AetherGrapeEngine

@GrabExclude can now be used to exclude certain transitive dependencies.
In Aether (Maven), exclusions are applied to an individual dependency
rather than being global. In Grape, exclusions are global.
AetherGrapeEngine adheres to the Grape convention by applying every
exclusion create by @GrabExclude to every dependency, effectively making
them global.

spring-boot-cli/src/main/java/org/springframework/boot/cli/compiler/grape/AetherGrapeEngine.java

@@ -139,8 +139,9 @@ public class AetherGrapeEngine implements GrapeEngine {
 
 	@Override
 	public Object grab(Map args, Map... dependencyMaps) {
+		List<Exclusion> exclusions = createExclusions(args);
+		List<Dependency> dependencies = createDependencies(dependencyMaps, exclusions);
 		try {
-			List<Dependency> dependencies = createDependencies(dependencyMaps);
 			List<File> files = resolve(dependencies);
 			GroovyClassLoader classLoader = getClassLoader(args);
 			for (File file : files) {
@@ -156,25 +157,43 @@ public class AetherGrapeEngine implements GrapeEngine {
 		return null;
 	}
 
-	private GroovyClassLoader getClassLoader(Map args) {
-		GroovyClassLoader classLoader = (GroovyClassLoader) args.get("classLoader");
-		return (classLoader == null ? this.classLoader : classLoader);
+	@SuppressWarnings("unchecked")
+	private List<Exclusion> createExclusions(Map<?, ?> args) {
+		List<Exclusion> exclusions = new ArrayList<Exclusion>();
+		List<Map<String, Object>> exclusionMaps = (List<Map<String, Object>>) args
+				.get("excludes");
+		if (exclusionMaps != null) {
+			for (Map<String, Object> exclusionMap : exclusionMaps) {
+				exclusions.add(createExclusion(exclusionMap));
+			}
+		}
+		return exclusions;
+	}
+
+	private Exclusion createExclusion(Map<String, Object> exclusionMap) {
+		String group = (String) exclusionMap.get("group");
+		String module = (String) exclusionMap.get("module");
+		return new Exclusion(group, module, "*", "*");
 	}
 
-	private List<Dependency> createDependencies(Map<?, ?>... dependencyMaps) {
+	private List<Dependency> createDependencies(Map<?, ?>[] dependencyMaps,
+			List<Exclusion> exclusions) {
 		List<Dependency> dependencies = new ArrayList<Dependency>(dependencyMaps.length);
 		for (Map<?, ?> dependencyMap : dependencyMaps) {
-			dependencies.add(createDependency(dependencyMap));
+			dependencies.add(createDependency(dependencyMap, exclusions));
 		}
 		return dependencies;
 	}
 
-	private Dependency createDependency(Map<?, ?> dependencyMap) {
+	private Dependency createDependency(Map<?, ?> dependencyMap,
+			List<Exclusion> exclusions) {
 		Artifact artifact = createArtifact(dependencyMap);
 		if (isTransitive(dependencyMap)) {
-			return new Dependency(artifact, JavaScopes.COMPILE);
+			return new Dependency(artifact, JavaScopes.COMPILE, false, exclusions);
+		}
+		else {
+			return new Dependency(artifact, JavaScopes.COMPILE, null, WILDCARD_EXCLUSION);
 		}
-		return new Dependency(artifact, JavaScopes.COMPILE, null, WILDCARD_EXCLUSION);
 	}
 
 	private Artifact createArtifact(Map<?, ?> dependencyMap) {
@@ -216,6 +235,11 @@ public class AetherGrapeEngine implements GrapeEngine {
 		return files;
 	}
 
+	private GroovyClassLoader getClassLoader(Map args) {
+		GroovyClassLoader classLoader = (GroovyClassLoader) args.get("classLoader");
+		return (classLoader == null ? this.classLoader : classLoader);
+	}
+
 	@Override
 	public void addResolver(Map<String, Object> args) {
 		String name = (String) args.get("name");

spring-boot-cli/src/test/java/org/springframework/boot/cli/compiler/grape/AetherGrapeEngineTests.java

@@ -18,6 +18,7 @@ package org.springframework.boot.cli.compiler.grape;
 
 import groovy.lang.GroovyClassLoader;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -47,6 +48,20 @@ public class AetherGrapeEngineTests {
 		assertEquals(6, this.groovyClassLoader.getURLs().length);
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void dependencyResolutionWithExclusions() {
+		Map<String, Object> args = new HashMap<String, Object>();
+		args.put("excludes",
+				Arrays.asList(createExclusion("org.springframework", "spring-core")));
+
+		this.grapeEngine.grab(args,
+				createDependency("org.springframework", "spring-jdbc", "3.2.4.RELEASE"),
+				createDependency("org.springframework", "spring-beans", "3.2.4.RELEASE"));
+
+		assertEquals(4, this.groovyClassLoader.getURLs().length);
+	}
+
 	@Test
 	public void nonTransitiveDependencyResolution() {
 		Map<String, Object> args = new HashMap<String, Object>();
@@ -117,4 +132,11 @@ public class AetherGrapeEngineTests {
 		resolver.put("root", url);
 		return resolver;
 	}
+
+	private Map<String, Object> createExclusion(String group, String module) {
+		Map<String, Object> exclusion = new HashMap<String, Object>();
+		exclusion.put("group", group);
+		exclusion.put("module", module);
+		return exclusion;
+	}
 }