LogstashMarker refactoring

src/main/java/net/logstash/logback/argument/DeferredStructuredArgument.java

@@ -50,8 +50,15 @@
  */
 public class DeferredStructuredArgument implements StructuredArgument {
 
+    /**
+     * Supplier for the deferred {@link StructuredArgument}
+     */
     private final Supplier<? extends StructuredArgument> structureArgumentSupplier;
 
+    /**
+     * Cached value of the structured argument returned by {@link #structureArgumentSupplier}.
+     * {@code null} until {@link #getSuppliedValue()} is first called.
+     */
     private volatile StructuredArgument suppliedValue;
 
     public DeferredStructuredArgument(Supplier<? extends StructuredArgument> structureArgumentSupplier) {
@@ -63,6 +70,12 @@ public void writeTo(JsonGenerator generator) throws IOException {
         getSuppliedValue().writeTo(generator);
     }
 
+    /**
+     * Get the deferred structure argument from the supplier or return it from the cache
+     * if already initialized.
+     * 
+     * @return the deferred structured argument
+     */
     private StructuredArgument getSuppliedValue() {
         if (suppliedValue == null) {
             synchronized (this) {

src/main/java/net/logstash/logback/marker/DeferredLogstashMarker.java

@@ -39,12 +39,20 @@
  * the supplier will be invoked when the first appender encodes the marker.
  * That same supplied value will be used when the next appender encodes the marker.</p>
  */
+@SuppressWarnings("serial")
 public class DeferredLogstashMarker extends LogstashMarker {
 
     public static final String DEFERRED_MARKER_NAME = "DEFERRED";
 
-    private final Supplier<? extends LogstashMarker>  logstashMarkerSupplier;
+    /**
+     * Supplier for the deferred marker
+     */
+    private final Supplier<? extends LogstashMarker> logstashMarkerSupplier;
 
+    /**
+     * Cached value of the marker returned by {@link #logstashMarkerSupplier}.
+     * {@code null} until {@link #getSuppliedValue()} is first called.
+     */
     private volatile LogstashMarker suppliedValue;
 
     public DeferredLogstashMarker(Supplier<? extends LogstashMarker> logstashMarkerSupplier) {
@@ -57,6 +65,12 @@ public void writeTo(JsonGenerator generator) throws IOException {
         writeMarker(generator, getSuppliedValue());
     }
 
+    /**
+     * Get the deferred marker from the supplier or return it from the cache
+     * if already initialized.
+     * 
+     * @return the deferred marker
+     */
     private LogstashMarker getSuppliedValue() {
         if (suppliedValue == null) {
             synchronized (this) {
@@ -82,8 +96,7 @@ private void writeMarker(JsonGenerator generator, Marker marker) throws IOExcept
 
         if (marker.hasReferences()) {
             for (Iterator<Marker> i = marker.iterator(); i.hasNext();) {
-                Marker next = i.next();
-                writeMarker(generator, next);
+                writeMarker(generator, i.next());
             }
         }
     }

src/main/java/net/logstash/logback/marker/EmptyLogstashMarker.java

@@ -36,6 +36,7 @@
  *     }
  * </pre>
  */
+@SuppressWarnings("serial")
 public class EmptyLogstashMarker extends LogstashMarker implements StructuredArgument {
 
     public static final String EMPTY_MARKER_NAME = "EMPTY";
@@ -53,4 +54,14 @@ public void writeTo(JsonGenerator generator) throws IOException {
     protected String toStringSelf() {
         return "";
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        return obj instanceof EmptyLogstashMarker && super.equals(obj);
+    }
+
+    @Override
+    public int hashCode() {
+        return super.hashCode();
+    }
 }

src/main/java/net/logstash/logback/marker/LogstashBasicMarker.java

@@ -18,68 +18,29 @@
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.slf4j.Marker;
 
-/* Copy of {@link org.slf4j.helpers.BasicMarker} from slf4j-api v1.7.31, with minor changes:
- * 1. make the constructor public so that it can be extended in other packages
- * 2. add getReferences() method
-
- * slf4j-api, {@link org.slf4j.helpers.BasicMarker}, and the portions
- * of this class that have been copied from BasicMarker are provided under
- * the MIT License copied here:
- * 
- * Copyright (c) 2004-2011 QOS.ch
- * All rights reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
- * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
- * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- */
 /**
- * A simple implementation of the {@link Marker} interface.
- *
- * @author Ceki Gülcü
- * @author Joern Huxhorn
-*/
+ * A simple implementation of the SLF4J {@link Marker} interface.
+ */
 @SuppressWarnings("serial")
-public class LogstashBasicMarker implements Marker {
+class LogstashBasicMarker implements Marker {
 
-    private static final String OPEN = "[ ";
-    private static final String CLOSE = " ]";
-    private static final String SEP = ", ";
-
+    /**
+     * The marker name
+     */
     private final String name;
-    private final List<Marker> referenceList = new CopyOnWriteArrayList<>();
 
-    /*
-     * BEGIN Modification in logstash-logback-encoder to make this constructor public
-     */
-    public LogstashBasicMarker(String name) {
-    /*
-     * END Modification in logstash-logback-encoder to make this constructor public
+    /**
+     * Referenced markers - initialized the first time a marker is added
      */
-        if (name == null) {
-            throw new IllegalArgumentException("A marker name cannot be null");
-        }
-        this.name = name;
+    private volatile List<Marker> referenceList;
+
+    LogstashBasicMarker(String name) {
+        this.name = Objects.requireNonNull(name);
     }
 
     /**
@@ -95,9 +56,7 @@ public String getName() {
      */
     @Override
     public void add(Marker reference) {
-        if (reference == null) {
-            throw new IllegalArgumentException("A null value cannot be added to a Marker as reference.");
-        }
+        Objects.requireNonNull(reference);
 
         // no point in adding the reference multiple times
         if (this.contains(reference)) {
@@ -107,6 +66,13 @@ public void add(Marker reference) {
             return;
         }
 
+        if (referenceList == null) {
+            synchronized (this) {
+                if (referenceList == null) {
+                    referenceList = new CopyOnWriteArrayList<>();
+                }
+            }
+        }
         referenceList.add(reference);
     }
 
@@ -115,7 +81,7 @@ public void add(Marker reference) {
      */
     @Override
     public boolean hasReferences() {
-        return !referenceList.isEmpty();
+        return referenceList != null && !referenceList.isEmpty();
     }
 
     /**
@@ -132,36 +98,30 @@ public boolean hasChildren() {
      */
     @Override
     public Iterator<Marker> iterator() {
-        return referenceList.iterator();
+        if (referenceList == null) {
+            return Collections.emptyIterator();
+        } else {
+            return referenceList.iterator();
+        }
     }
 
-    /*
-     * BEGIN Modification in logstash-logback-encoder to add this method
-     */
-    protected List<Marker> getReferences() {
-        return Collections.unmodifiableList(referenceList);
-    }
-    /*
-     * END Modification in logstash-logback-encoder to add this method
-     */
-
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean remove(Marker referenceToRemove) {
-        return referenceList.remove(referenceToRemove);
+        if (referenceList != null) {
+            return referenceList.remove(referenceToRemove);
+        } else {
+            return false;
+        }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean contains(Marker other) {
-        if (other == null) {
-            throw new IllegalArgumentException("Other cannot be null");
-        }
-
         if (this.equals(other)) {
             return true;
         }
@@ -182,10 +142,6 @@ public boolean contains(Marker other) {
      */
     @Override
     public boolean contains(String name) {
-        if (name == null) {
-            throw new IllegalArgumentException("Other cannot be null");
-        }
-
         if (this.name.equals(name)) {
             return true;
         }
@@ -234,16 +190,15 @@ public String toString() {
             return this.getName();
         }
         StringBuilder sb = new StringBuilder(this.getName())
-                .append(' ')
-                .append(OPEN);
+                .append(" [ ");
         Iterator<Marker> it = this.iterator();
         while (it.hasNext()) {
             sb.append(it.next().getName());
             if (it.hasNext()) {
-                sb.append(SEP);
+                sb.append(", ");
             }
         }
-        sb.append(CLOSE);
+        sb.append(" ]");
 
         return sb.toString();
     }

src/main/java/net/logstash/logback/marker/ObjectAppendingMarker.java

@@ -76,26 +76,26 @@ public class ObjectAppendingMarker extends SingleFieldAppendingMarker {
      * The object to write as the field's value.
      * Can be a {@link String}, {@link Number}, array, or some other object that can be processed by an {@link ObjectMapper}
      */
-    private final Object object;
+    private final Object fieldValue;
 
-    public ObjectAppendingMarker(String fieldName, Object object) {
+    public ObjectAppendingMarker(String fieldName, Object fieldValue) {
         super(MARKER_NAME, fieldName);
-        this.object = object;
+        this.fieldValue = fieldValue;
     }
 
-    public ObjectAppendingMarker(String fieldName, Object object, String messageFormatPattern) {
+    public ObjectAppendingMarker(String fieldName, Object fieldValue, String messageFormatPattern) {
         super(MARKER_NAME, fieldName, messageFormatPattern);
-        this.object = object;
+        this.fieldValue = fieldValue;
     }
 
     @Override
     protected void writeFieldValue(JsonGenerator generator) throws IOException {
-        generator.writeObject(object);
+        generator.writeObject(fieldValue);
     }
 
     @Override
     public Object getFieldValue() {
-        return StructuredArguments.toString(object);
+        return StructuredArguments.toString(fieldValue);
     }
 
     @Override
@@ -111,15 +111,15 @@ public boolean equals(Object obj) {
         }
 
         ObjectAppendingMarker other = (ObjectAppendingMarker) obj;
-        return Objects.equals(this.object, other.object);
+        return Objects.equals(this.fieldValue, other.fieldValue);
     }
 
     @Override
     public int hashCode() {
         final int prime = 31;
         int result = 1;
         result = prime * result + super.hashCode();
-        result = prime * result + (this.object == null ? 0 : this.object.hashCode());
+        result = prime * result + (this.fieldValue == null ? 0 : this.fieldValue.hashCode());
         return result;
     }
 }

src/main/java/net/logstash/logback/marker/ObjectFieldsAppendingMarker.java

@@ -91,8 +91,8 @@ public class ObjectFieldsAppendingMarker extends LogstashMarker implements Struc
      *
      * Since apps will typically serialize the same types of objects repeatedly, they shouldn't grow too much.
      */
-    private static final ConcurrentHashMap<Class<?>, JsonSerializer<Object>> beanSerializers = new ConcurrentHashMap<Class<?>, JsonSerializer<Object>>();
-    private static final ConcurrentHashMap<ObjectMapper, SerializerProvider> serializerProviders = new ConcurrentHashMap<ObjectMapper, SerializerProvider>();
+    private static final ConcurrentHashMap<Class<?>, JsonSerializer<Object>> beanSerializers = new ConcurrentHashMap<>();
+    private static final ConcurrentHashMap<ObjectMapper, SerializerProvider> serializerProviders = new ConcurrentHashMap<>();
 
     public ObjectFieldsAppendingMarker(Object object) {
         super(MARKER_NAME);