Remove duplicate code in new metrics code

Refactor BufferMetricReader, CounterBuffers and GaugeBuffers to reduce
duplicate code.

Closes gh-3117

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/buffer/BufferMetricReader.java

@@ -49,28 +49,6 @@ public class BufferMetricReader implements MetricReader, PrefixMetricReader {
 		this.gauges = gauges;
 	}
 
-	@Override
-	public Iterable<Metric<?>> findAll(String prefix) {
-		final List<Metric<?>> metrics = new ArrayList<Metric<?>>();
-		this.counters.forEach(Pattern.compile(prefix + ".*").asPredicate(),
-				new BiConsumer<String, LongBuffer>() {
-					@Override
-					public void accept(String name, LongBuffer value) {
-						metrics.add(new Metric<Long>(name, value.getValue(), new Date(
-								value.getTimestamp())));
-					}
-				});
-		this.gauges.forEach(Pattern.compile(prefix + ".*").asPredicate(),
-				new BiConsumer<String, DoubleBuffer>() {
-					@Override
-					public void accept(String name, DoubleBuffer value) {
-						metrics.add(new Metric<Double>(name, value.getValue(), new Date(
-								value.getTimestamp())));
-					}
-				});
-		return metrics;
-	}
-
 	@Override
 	public Metric<?> findOne(final String name) {
 		LongBuffer buffer = this.counters.find(name);
@@ -88,27 +66,40 @@ public class BufferMetricReader implements MetricReader, PrefixMetricReader {
 
 	@Override
 	public Iterable<Metric<?>> findAll() {
+		return findAll(this.all);
+	}
+
+	@Override
+	public Iterable<Metric<?>> findAll(String prefix) {
+		return findAll(Pattern.compile(prefix + ".*").asPredicate());
+	}
+
+	@Override
+	public long count() {
+		return this.counters.count() + this.gauges.count();
+	}
+
+	private Iterable<Metric<?>> findAll(Predicate<String> predicate) {
 		final List<Metric<?>> metrics = new ArrayList<Metric<?>>();
-		this.counters.forEach(this.all, new BiConsumer<String, LongBuffer>() {
+		this.counters.forEach(predicate, new BiConsumer<String, LongBuffer>() {
+
 			@Override
 			public void accept(String name, LongBuffer value) {
 				metrics.add(new Metric<Long>(name, value.getValue(), new Date(value
 						.getTimestamp())));
 			}
+
 		});
-		this.gauges.forEach(this.all, new BiConsumer<String, DoubleBuffer>() {
+		this.gauges.forEach(predicate, new BiConsumer<String, DoubleBuffer>() {
+
 			@Override
 			public void accept(String name, DoubleBuffer value) {
 				metrics.add(new Metric<Double>(name, value.getValue(), new Date(value
 						.getTimestamp())));
 			}
+
 		});
 		return metrics;
 	}
 
-	@Override
-	public long count() {
-		return this.counters.count() + this.gauges.count();
-	}
-
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/buffer/CounterBuffers.java

@@ -52,12 +52,7 @@ public class CounterBuffers {
 	}
 
 	public void get(final String name, final Consumer<LongBuffer> consumer) {
-		read(name, new Consumer<LongBuffer>() {
-			@Override
-			public void accept(LongBuffer adder) {
-				consumer.accept(adder);
-			}
-		});
+		read(name, consumer);
 	}
 
 	public void increment(final String name, final long delta) {
@@ -83,12 +78,7 @@ public class CounterBuffers {
 	}
 
 	private void read(final String name, final Consumer<LongBuffer> consumer) {
-		acceptInternal(name, new Consumer<LongBuffer>() {
-			@Override
-			public void accept(LongBuffer adder) {
-				consumer.accept(adder);
-			}
-		});
+		acceptInternal(name, consumer);
 	}
 
 	private void write(final String name, final Consumer<LongBuffer> consumer) {

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/buffer/GaugeBuffers.java

@@ -52,12 +52,7 @@ public class GaugeBuffers {
 	}
 
 	public void get(final String name, final Consumer<DoubleBuffer> consumer) {
-		acceptInternal(name, new Consumer<DoubleBuffer>() {
-			@Override
-			public void accept(DoubleBuffer value) {
-				consumer.accept(value);
-			}
-		});
+		acceptInternal(name, consumer);
 	}
 
 	public void set(final String name, final double value) {