Add SmartImportCustomizer

Only imports classes with names that are not already
imported into teh SourceUnit

Fixes gh-983

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

@@ -264,7 +264,7 @@ public class GroovyCompiler {
 		public void call(SourceUnit source, GeneratorContext context, ClassNode classNode)
 				throws CompilationFailedException {
 
-			ImportCustomizer importCustomizer = new ImportCustomizer();
+			ImportCustomizer importCustomizer = new SmartImportCustomizer(source, context, classNode);
 			ClassNode mainClassNode = getMainClass(source.getAST().getClasses());
 
 			// Additional auto configuration

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

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2013-2014 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 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 org.springframework.boot.cli.compiler;
+
+import org.codehaus.groovy.ast.ClassHelper;
+import org.codehaus.groovy.ast.ClassNode;
+import org.codehaus.groovy.classgen.GeneratorContext;
+import org.codehaus.groovy.control.SourceUnit;
+import org.codehaus.groovy.control.customizers.ImportCustomizer;
+
+/**
+ * Smart extension of {@link ImportCustomizer} that will only add a specific import if a
+ * class with the same name is not already explicitly imported.
+ * 
+ * @author Dave Syer
+ *
+ * @since 1.1
+ */
+class SmartImportCustomizer extends ImportCustomizer {
+
+	private SourceUnit source;
+
+	public SmartImportCustomizer(SourceUnit source, GeneratorContext context,
+			ClassNode classNode) {
+		this.source = source;
+	}
+
+	@Override
+	public ImportCustomizer addImport(String alias, String className) {
+		if (source.getAST()
+				.getImport(ClassHelper.make(className).getNameWithoutPackage()) == null) {
+			super.addImport(alias, className);
+		}
+		return this;
+	}
+
+	@Override
+	public ImportCustomizer addImports(String... imports) {
+		for (String alias : imports) {
+			if (source.getAST()
+					.getImport(ClassHelper.make(alias).getNameWithoutPackage()) == null) {
+				super.addImports(alias);
+			}
+		}
+		return this;
+	}
+
+}