Add command to display all library templates supported

for a specific language

modules/swagger-codegen/src/main/java/io/swagger/codegen/CodegenConfig.java

@@ -109,6 +109,8 @@ public interface CodegenConfig {
 
     void setSkipOverwrite(boolean skipOverwrite);
 
+    Map<String, String> supportedLibraries();
+
     void setLibrary(String library);
 
     /**

modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java

@@ -81,6 +81,7 @@ public class DefaultCodegen {
     protected List<CliOption> cliOptions = new ArrayList<CliOption>();
     protected boolean skipOverwrite;
     protected boolean supportsInheritance = false;
+    protected Map<String, String> supportedLibraries = new HashMap<String, String>();
     protected String library = null;
 
     public List<CliOption> cliOptions() {
@@ -1389,7 +1390,16 @@ public class DefaultCodegen {
         this.skipOverwrite = skipOverwrite;
     }
 
+    /**
+     * All library templates supported.
+     */
+    public Map<String, String> supportedLibraries() {
+        return supportedLibraries;
+    }
+
     public void setLibrary(String library) {
+        if (library != null && !supportedLibraries.containsKey(library))
+            throw new RuntimeException("unknown library: " + library);
         this.library = library;
     }
 

modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java

@@ -266,7 +266,7 @@ public class DefaultGenerator extends AbstractGenerator implements Generator {
 
                 String templateFile = null;
                 String library = config.getLibrary();
-                if (library != null) {
+                if (library != null && !"".equals(library)) {
                     String libTemplateFile = config.templateDir() + File.separator +
                         "libraries" + File.separator + library + File.separator +
                         support.templateFile;

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/JavaClientCodegen.java

@@ -61,6 +61,9 @@ public class JavaClientCodegen extends DefaultCodegen implements CodegenConfig {
         cliOptions.add(new CliOption("artifactId", "artifactId in generated pom.xml"));
         cliOptions.add(new CliOption("artifactVersion", "artifact version in generated pom.xml"));
         cliOptions.add(new CliOption("sourceFolder", "source folder for generated code"));
+
+        supportedLibraries.put("", "HTTP client: Jersey client 1.18. JSON processing: Jackson 2.4.2");
+        supportedLibraries.put("jersey2", "HTTP client: Jersey client 2.6");
     }
 
     public CodegenType getTag() {