Make post processors generic and be able to chain them (#163)

Author: fonimus

samples/complete/src/main/java/com/github/fonimus/ssh/shell/complete/DemoConfiguration.java

@@ -29,8 +29,12 @@
 import org.springframework.scheduling.annotation.SchedulingConfigurer;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.scheduling.config.ScheduledTaskRegistrar;
+import org.springframework.util.CollectionUtils;
 
 import javax.sql.DataSource;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
 import java.util.List;
 
 /**
@@ -47,17 +51,53 @@ public DemoConfiguration(TasksCommand tasksCommand) {
     }
 
     @Bean
-    public PostProcessor<String> quotePostProcessor() {
-        return new PostProcessor<String>() {
+    public PostProcessor<String, String> quotePostProcessor() {
+        return new PostProcessor<String, String>() {
 
             @Override
             public String getName() {
                 return "quote";
             }
 
             @Override
-            public String process(String result, List<String> parameters) {
-                return "'" + result + "'";
+            public String process(String input, List<String> parameters) {
+                return "'" + input + "'";
+            }
+        };
+    }
+
+    @Bean
+    public PostProcessor<String, ZonedDateTime> datePostProcessor() {
+        return new PostProcessor<String, ZonedDateTime>() {
+
+            @Override
+            public String getName() {
+                return "date";
+            }
+
+            @Override
+            public ZonedDateTime process(String input, List<String> parameters) {
+                return ZonedDateTime.parse(input);
+            }
+        };
+    }
+
+    @Bean
+    public PostProcessor<ZonedDateTime, ZonedDateTime> uctPostProcessor() {
+        return new PostProcessor<ZonedDateTime, ZonedDateTime>() {
+
+            @Override
+            public String getName() {
+                return "zoned";
+            }
+
+            @Override
+            public ZonedDateTime process(ZonedDateTime input, List<String> parameters) {
+                String zone = "UTC";
+                if (!CollectionUtils.isEmpty(parameters)) {
+                    zone = parameters.get(0);
+                }
+                return input.withZoneSameInstant(ZoneId.of(zone));
             }
         };
     }

starter/src/main/java/com/github/fonimus/ssh/shell/ExtendedShell.java

@@ -46,6 +46,7 @@
 public class ExtendedShell
         extends Shell {
 
+    @SuppressWarnings("rawtypes")
     private final ResultHandler resultHandler;
 
     private final List<String> postProcessorNames = new ArrayList<>();
@@ -56,7 +57,7 @@ public class ExtendedShell
      * @param resultHandler  result handler
      * @param postProcessors post processors list
      */
-    public ExtendedShell(ResultHandler resultHandler, List<PostProcessor> postProcessors) {
+    public ExtendedShell(ResultHandler resultHandler, List<PostProcessor<?,?>> postProcessors) {
         super(resultHandler);
         this.resultHandler = resultHandler;
         if (postProcessors != null) {

starter/src/main/java/com/github/fonimus/ssh/shell/SshShellAutoConfiguration.java

@@ -138,7 +138,7 @@ public void init() {
 
     @Bean
     @Primary
-    public ExtendedShell sshShell(@Qualifier("main") ResultHandler<Object> resultHandler, List<PostProcessor> postProcessors) {
+    public ExtendedShell sshShell(@Qualifier("main") ResultHandler<Object> resultHandler, List<PostProcessor<?,?>> postProcessors) {
         return new ExtendedShell(new TypePostProcessorResultHandler(resultHandler, postProcessors), postProcessors);
     }
 

starter/src/main/java/com/github/fonimus/ssh/shell/commands/PostProcessorsCommand.java

@@ -46,10 +46,10 @@ public class PostProcessorsCommand extends AbstractCommand {
     public static final String GROUP = "postprocessors";
     public static final String COMMAND_POST_PROCESSORS = "postprocessors";
 
-    private final List<PostProcessor> postProcessors;
+    private final List<PostProcessor<?, ?>> postProcessors;
 
     public PostProcessorsCommand(SshShellHelper helper, SshShellProperties properties,
-                                 List<PostProcessor> postProcessors) {
+                                 List<PostProcessor<?, ?>> postProcessors) {
         super(helper, properties, properties.getCommands().getPostprocessors());
         this.postProcessors = new ArrayList<>(postProcessors);
         this.postProcessors.sort(Comparator.comparing(PostProcessor::getName));
@@ -60,11 +60,14 @@ public PostProcessorsCommand(SshShellHelper helper, SshShellProperties propertie
     public CharSequence postprocessors() {
         AttributedStringBuilder result = new AttributedStringBuilder();
         result.append("Available Post-Processors\n\n", AttributedStyle.BOLD);
-        for (PostProcessor postProcessor : postProcessors) {
-            result.append("\t" + postProcessor.getName() + ": ", AttributedStyle.BOLD);
-            Class<?> cls =
-                    ((Class) ((ParameterizedType) (postProcessor.getClass().getGenericInterfaces())[0]).getActualTypeArguments()[0]);
-            result.append(cls.getName() + "\n", AttributedStyle.DEFAULT);
+        for (PostProcessor<?, ?> postProcessor : postProcessors) {
+            result.append("\t" + postProcessor.getName() + ":\n", AttributedStyle.BOLD);
+            Class<?> input =
+                    ((Class<?>) ((ParameterizedType) (postProcessor.getClass().getGenericInterfaces())[0]).getActualTypeArguments()[0]);
+            Class<?> output =
+                    ((Class<?>) ((ParameterizedType) (postProcessor.getClass().getGenericInterfaces())[0]).getActualTypeArguments()[1]);
+            result.append("\t\tinput  : " + input.getName() + "\n", AttributedStyle.DEFAULT);
+            result.append("\t\toutput : " + output.getName() + "\n", AttributedStyle.DEFAULT);
         }
 
         return result;

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/PostProcessor.java

@@ -21,9 +21,9 @@
 /**
  * Post processor interface
  */
-public interface PostProcessor<T> {
+public interface PostProcessor<I, O> {
 
     String getName();
 
-    String process(T result, List<String> parameters) throws PostProcessorException;
+    O process(I result, List<String> parameters) throws PostProcessorException;
 }

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/TypePostProcessorResultHandler.java

@@ -35,14 +35,14 @@ public class TypePostProcessorResultHandler
 
     public static final ThreadLocal<Throwable> THREAD_CONTEXT = ThreadLocal.withInitial(() -> null);
 
-    private ResultHandler<Object> resultHandler;
+    private final ResultHandler<Object> resultHandler;
 
-    private Map<String, PostProcessor> postProcessorMap = new HashMap<>();
+    private final Map<String, PostProcessor<?,?>> postProcessorMap = new HashMap<>();
 
-    public TypePostProcessorResultHandler(ResultHandler<Object> resultHandler, List<PostProcessor> postProcessorList) {
+    public TypePostProcessorResultHandler(ResultHandler<Object> resultHandler, List<PostProcessor<?,?>> postProcessorList) {
         this.resultHandler = resultHandler;
         if (postProcessorList != null) {
-            for (PostProcessor postProcessor : postProcessorList) {
+            for (PostProcessor<?,?> postProcessor : postProcessorList) {
                 if (this.postProcessorMap.containsKey(postProcessor.getName())) {
                     LOGGER.warn("Unable to register post processor for name [{}], it has already been registered",
                             postProcessor.getName());
@@ -54,6 +54,7 @@ public TypePostProcessorResultHandler(ResultHandler<Object> resultHandler, List<
         }
     }
 
+    @SuppressWarnings({"rawtypes", "unchecked"})
     @Override
     public void handleResult(Object result) {
         if (result == null) {
@@ -73,7 +74,7 @@ public void handleResult(Object result) {
                     continue;
                 }
                 Class<?> cls =
-                        ((Class) ((ParameterizedType) (postProcessor.getClass().getGenericInterfaces())[0]).getActualTypeArguments()[0]);
+                        ((Class<?>) ((ParameterizedType) (postProcessor.getClass().getGenericInterfaces())[0]).getActualTypeArguments()[0]);
                 if (!cls.isAssignableFrom(obj.getClass())) {
                     printLogWarn("Post processor [" + name + "] can only apply to class [" + cls.getName() +
                             "] (current object class is " + obj.getClass().getName() + ")");
@@ -82,7 +83,7 @@ public void handleResult(Object result) {
                             postProcessorObject.getParameters());
                     try {
                         obj = postProcessor.process(obj, postProcessorObject.getParameters());
-                    } catch (PostProcessorException e) {
+                    } catch (Exception e) {
                         printError(e.getMessage());
                         return;
                     }

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/provided/GrepPostProcessor.java

@@ -26,7 +26,7 @@
  */
 @Slf4j
 public class GrepPostProcessor
-        implements PostProcessor<String> {
+        implements PostProcessor<String, String> {
 
     @Override
     public String getName() {
@@ -45,7 +45,7 @@ public String process(String result, List<String> parameters) {
                     sb.append(line).append("\n");
                 }
             }
-            return sb.toString().isEmpty() ? sb.toString() : sb.toString().substring(0, sb.toString().length() - 1);
+            return sb.toString().isEmpty() ? sb.toString() : sb.substring(0, sb.toString().length() - 1);
         }
     }
 

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/provided/HighlightPostProcessor.java

@@ -28,7 +28,7 @@
  */
 @Slf4j
 public class HighlightPostProcessor
-        implements PostProcessor<String> {
+        implements PostProcessor<String, String> {
 
     @Override
     public String getName() {

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/provided/JsonPointerPostProcessor.java

@@ -29,7 +29,7 @@
  */
 @Slf4j
 public class JsonPointerPostProcessor
-        implements PostProcessor<String> {
+        implements PostProcessor<String, String> {
 
     private static final ObjectMapper MAPPER = new ObjectMapper();
 

starter/src/main/java/com/github/fonimus/ssh/shell/postprocess/provided/PrettyJsonPostProcessor.java

@@ -29,7 +29,7 @@
  */
 @Slf4j
 public class PrettyJsonPostProcessor
-        implements PostProcessor<Object> {
+        implements PostProcessor<Object, String> {
 
     private static final ObjectMapper MAPPER = new ObjectMapper();