use Java 8 lambda (#632)

Author: xuwei-k

handlebars-guava-cache/src/main/java/com/github/jknack/handlebars/cache/GuavaTemplateCache.java

@@ -20,7 +20,6 @@
 import static org.apache.commons.lang3.Validate.notNull;
 
 import java.io.IOException;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 
 import com.github.jknack.handlebars.HandlebarsException;
@@ -72,12 +71,7 @@ public Template get(final TemplateSource source, final Parser parser) throws IOE
     notNull(source, "The source is required.");
     notNull(parser, "The parser is required.");
     try {
-      return cache.get(key(source), new Callable<Template>() {
-        @Override
-        public Template call() throws IOException {
-          return parser.parse(source);
-        }
-      });
+      return cache.get(key(source), () -> parser.parse(source));
     } catch (ExecutionException ex) {
       throw launderThrowable(source, ex.getCause());
     }

handlebars-guava-cache/src/main/java/com/github/jknack/handlebars/io/GuavaCachedTemplateLoader.java

@@ -19,7 +19,6 @@
 
 import java.io.IOException;
 import java.nio.charset.Charset;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 
@@ -79,12 +78,7 @@ public static GuavaCachedTemplateLoader cacheWithExpiration(
    */
   public TemplateSource sourceAt(final String location) throws IOException {
     try {
-      return cache.get(location, new Callable<TemplateSource>() {
-        @Override
-        public TemplateSource call() throws Exception {
-          return delegate.sourceAt(location);
-        }
-      });
+      return cache.get(location, () -> delegate.sourceAt(location));
     } catch (ExecutionException e) {
       Throwables.propagateIfPossible(e.getCause(), IOException.class);
       throw Throwables.propagate(e.getCause());

handlebars-maven-plugin/src/main/java/com/github/jknack/handlebars/maven/PrecompilePlugin.java

@@ -267,12 +267,7 @@ protected void doExecute() throws Exception {
    * @param handlebars The handlebars object.
    */
   private void silentHelpers(final Handlebars handlebars) {
-    handlebars.registerHelper(HelperRegistry.HELPER_MISSING, new Helper<Object>() {
-      @Override
-      public Object apply(final Object context, final Options options) throws IOException {
-        return null;
-      }
-    });
+    handlebars.registerHelper(HelperRegistry.HELPER_MISSING, (context, options) -> null);
   }
 
   /**

handlebars-proto/src/main/java/com/github/jknack/handlebars/server/HbsServer.java

@@ -164,14 +164,10 @@ public static void run(final Options args) throws Exception {
      * Helper wont work in the stand-alone version, so we add a default helper
      * that render the plain text.
      */
-    handlebars.registerHelper(HelperRegistry.HELPER_MISSING, new Helper<Object>() {
-      @Override
-      public Object apply(final Object context,
-          final com.github.jknack.handlebars.Options options)
-          throws IOException {
-        return new Handlebars.SafeString(options.fn.text());
-      }
-    });
+    handlebars.registerHelper(
+      HelperRegistry.HELPER_MISSING,
+      (context, options) -> new Handlebars.SafeString(options.fn.text())
+    );
     handlebars.registerHelper("json", Jackson2Helper.INSTANCE);
     handlebars.registerHelper("md", new MarkdownHelper());
     // String helpers
@@ -180,15 +176,12 @@ public Object apply(final Object context,
     HumanizeHelper.register(handlebars);
 
     final Server server = new Server(args.port);
-    Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
-      @Override
-      public void run() {
-        logger.info("Hope you enjoy it! bye!");
-        try {
-          server.stop();
-        } catch (Exception ex) {
-          logger.info("Can't stop the server", ex);
-        }
+    Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+      logger.info("Hope you enjoy it! bye!");
+      try {
+        server.stop();
+      } catch (Exception ex) {
+        logger.info("Can't stop the server", ex);
       }
     }));
 

handlebars/src/main/java/com/github/jknack/handlebars/EscapingStrategy.java

@@ -105,36 +105,19 @@ public CharSequence escape(final CharSequence value) {
   EscapingStrategy HBS4 = HTML_ENTITY;
 
   /** Escape variable for CSV. */
-  EscapingStrategy CSV = new EscapingStrategy() {
-    @Override
-    public CharSequence escape(final CharSequence value) {
-      return value == null ? null : StringEscapeUtils.escapeCsv(value.toString());
-    }
-  };
+  EscapingStrategy CSV = value ->
+    value == null ? null : StringEscapeUtils.escapeCsv(value.toString());
 
   /** Escape variable for XML. */
-  EscapingStrategy XML = new EscapingStrategy() {
-    @Override
-    public CharSequence escape(final CharSequence value) {
-      return value == null ? null : StringEscapeUtils.escapeXml(value.toString());
-    }
-  };
+  EscapingStrategy XML = value ->
+    value == null ? null : StringEscapeUtils.escapeXml(value.toString());
 
   /** Escape variable for JavaScript. */
-  EscapingStrategy JS = new EscapingStrategy() {
-    @Override
-    public CharSequence escape(final CharSequence value) {
-      return value == null ? null : StringEscapeUtils.escapeEcmaScript(value.toString());
-    }
-  };
+  EscapingStrategy JS = value ->
+    value == null ? null : StringEscapeUtils.escapeEcmaScript(value.toString());
 
   /** NOOP escaping. */
-  EscapingStrategy NOOP = new EscapingStrategy() {
-    @Override
-    public CharSequence escape(final CharSequence value) {
-      return value;
-    }
-  };
+  EscapingStrategy NOOP = value -> value;
 
   /** Default escaping strategy. */
   EscapingStrategy DEF = HBS4;

handlebars/src/main/java/com/github/jknack/handlebars/Formatter.java

@@ -69,12 +69,7 @@ interface Chain {
    *
    * @author edgar
    */
-  Formatter.Chain NOOP = new Formatter.Chain() {
-    @Override
-    public Object format(final Object value) {
-      return value;
-    }
-  };
+  Formatter.Chain NOOP = value -> value;
 
   /**
    * Format a value if possible or call next formatter in the chain.

handlebars/src/main/java/com/github/jknack/handlebars/Handlebars.java

@@ -1437,14 +1437,12 @@ public Charset getCharset() {
    * @return Composite escape strategy.
    */
   private static EscapingStrategy newEscapeChain(final EscapingStrategy[] chain) {
-    return new EscapingStrategy() {
-      @Override public CharSequence escape(final CharSequence value) {
-        CharSequence result = value;
-        for (EscapingStrategy escape : chain) {
-          result = escape.escape(result);
-        }
-        return result;
+    return value -> {
+      CharSequence result = value;
+      for (EscapingStrategy escape : chain) {
+        result = escape.escape(result);
       }
+      return result;
     };
   }
 

handlebars/src/main/java/com/github/jknack/handlebars/cache/HighConcurrencyTemplateCache.java

@@ -20,7 +20,6 @@
 import static org.apache.commons.lang3.Validate.notNull;
 
 import java.io.IOException;
-import java.util.concurrent.Callable;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -162,12 +161,7 @@ private Template cacheGet(final TemplateSource source, final Parser parser) thro
   private FutureTask<Pair<TemplateSource, Template>> newTask(final TemplateSource source,
       final Parser parser) {
     return new FutureTask<>(
-        new Callable<Pair<TemplateSource, Template>>() {
-          @Override
-          public Pair<TemplateSource, Template> call() throws IOException {
-            return Pair.of(source, parser.parse(source));
-          }
-        });
+            () -> Pair.of(source, parser.parse(source)));
   }
 
   /**