Replace json-simple by own JSON serializer #89

Replace json-simple by own JSON writer and perform UTF-8 encoding within the JSON writer.

Motivation: json-simple produces a notable amount of garbage during JSON serialization. The default interchange format is String that concatenates data using StringBuilder.

The own implementation uses a facade to write bytes on an underlying stream. This reduces the garbage so data is not necessarily duplicated during serialization.

README.md

@@ -353,7 +353,6 @@ Versions/Dependencies
 --------------
 This project is built against following dependencies/versions:
 
-* json-simple 1.1.1
 * log4j 1.2.14
 * log4j2 2.5
 * Java Util Logging JDK Version 1.6

pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
@@ -58,11 +59,11 @@
         <test.withRedis>false</test.withRedis>
 
         <!-- Versions -->
-        <com.googlecode.json-simple.version>1.1.1</com.googlecode.json-simple.version>
         <log4j.version>1.2.14</log4j.version>
         <log4j2.version>2.3</log4j2.version>
         <junit.version>4.11</junit.version>
         <mockito.version>1.9.5</mockito.version>
+        <jackson.version>2.7.5</jackson.version>
         <jedis.version>2.8.1</jedis.version>
         <jedis-commons-pool2.version>2.4.2</jedis-commons-pool2.version>
         <slf4j-api.version>1.7.13</slf4j-api.version>
@@ -241,18 +242,6 @@
     </dependencyManagement>
 
     <dependencies>
-        <dependency>
-            <groupId>com.googlecode.json-simple</groupId>
-            <artifactId>json-simple</artifactId>
-            <version>${com.googlecode.json-simple.version}</version>
-            <exclusions>
-                <exclusion>
-                    <groupId>junit</groupId>
-                    <artifactId>junit</artifactId>
-                </exclusion>
-            </exclusions>
-        </dependency>
-
         <dependency>
             <groupId>log4j</groupId>
             <artifactId>log4j</artifactId>
@@ -336,6 +325,13 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+            <scope>test</scope>
+        </dependency>
+
         <!-- Redis Client -->
         <dependency>
             <groupId>redis.clients</groupId>

src/main/assembly/assembly.xml

@@ -27,7 +27,6 @@
         <dependencySet>
             <outputDirectory>/biz/paluch/logging/main</outputDirectory>
             <includes>
-                <include>com.googlecode.json-simple:json-simple</include>
                 <include>redis.clients:jedis</include>
                 <include>org.apache.commons:commons-pool2</include>
             </includes>

src/main/assembly/module.xml

@@ -3,7 +3,6 @@
 
     <resources>
         <resource-root path="${project.artifactId}-${project.version}.jar" />
-        <resource-root path="json-simple-${com.googlecode.json-simple.version}.jar" />
         <resource-root path="jedis-${jedis.version}.jar" />
         <resource-root path="commons-pool2-${jedis-commons-pool2.version}.jar" />
     </resources>

src/main/java/biz/paluch/logging/gelf/intern/GelfMessage.java

@@ -9,8 +9,6 @@
 import java.util.Map;
 import java.util.zip.GZIPOutputStream;
 
-import org.json.simple.JSONValue;
-
 /**
  * @author https://github.com/t0xa/gelfj
  * @author Mark Paluch
@@ -71,10 +69,11 @@ public class GelfMessage {
 
     private static final byte[] GELF_CHUNKED_ID = new byte[] { 0x1e, 0x0f };
     private static final BigDecimal TIME_DIVISOR = new BigDecimal(1000);
+    private static final byte[] NONE = lastFourAsciiBytes("none");
 
     private String version = GELF_VERSION;
     private String host;
-    private byte[] hostBytes = lastFourAsciiBytes("none");
+    private byte[] hostBytes = NONE;
     private String shortMessage;
     private String fullMessage;
     private long javaTimestamp;
@@ -96,25 +95,36 @@ public GelfMessage(String shortMessage, String fullMessage, long timestamp, Stri
     }
 
     public String toJson(String additionalFieldPrefix) {
-        Map<String, Object> map = new HashMap<String, Object>();
+        return new String(toJsonByteArray(additionalFieldPrefix), Charsets.UTF8);
+    }
 
-        if (!isEmpty(getHost())) {
-            map.put(FIELD_HOST, getHost());
-        }
+    public byte[] toJsonByteArray(String additionalFieldPrefix) {
+
+        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+        toJson(OutputAccessor.from(buffer), additionalFieldPrefix);
+
+        return buffer.toByteArray();
+    }
+
+    protected void toJson(OutputAccessor out, String additionalFieldPrefix) {
+
+        boolean hasFields = false;
+
+        JsonWriter.writeObjectStart(out);
+
+        hasFields = writeIfNotEmpty(out, hasFields, FIELD_HOST, getHost());
 
         if (!isEmpty(shortMessage)) {
-            map.put(FIELD_SHORT_MESSAGE, getShortMessage());
+            hasFields = writeIfNotEmpty(out, hasFields, FIELD_SHORT_MESSAGE, getShortMessage());
         }
 
-        if (!isEmpty(getFullMessage())) {
-            map.put(FIELD_FULL_MESSAGE, getFullMessage());
-        }
+        hasFields = writeIfNotEmpty(out, hasFields, FIELD_FULL_MESSAGE, getFullMessage());
 
         if (getJavaTimestamp() != 0) {
             if (GELF_VERSION_1_1.equals(version)) {
-                map.put(FIELD_TIMESTAMP, getTimestampAsBigDecimal().doubleValue());
+                hasFields = writeIfNotEmpty(out, hasFields, FIELD_TIMESTAMP, getTimestampAsBigDecimal().doubleValue());
             } else {
-                map.put(FIELD_TIMESTAMP, getTimestamp());
+                hasFields = writeIfNotEmpty(out, hasFields, FIELD_TIMESTAMP, getTimestampAsBigDecimal().toString());
             }
         }
 
@@ -127,14 +137,14 @@ public String toJson(String additionalFieldPrefix) {
                     // fallback on the default value
                     level = DEFAUL_LEVEL;
                 }
-                map.put(FIELD_LEVEL, level);
+                hasFields = writeIfNotEmpty(out, hasFields, FIELD_LEVEL, level);
             } else {
-                map.put(FIELD_LEVEL, getLevel());
+                hasFields = writeIfNotEmpty(out, hasFields, FIELD_LEVEL, getLevel());
             }
         }
 
         if (!isEmpty(getFacility())) {
-            map.put(FIELD_FACILITY, getFacility());
+            hasFields = writeIfNotEmpty(out, hasFields, FIELD_FACILITY, getFacility());
         }
 
         for (Map.Entry<String, String> additionalField : additonalFields.entrySet()) {
@@ -146,16 +156,47 @@ public String toJson(String additionalFieldPrefix) {
                 }
                 Object result = getAdditionalFieldValue(value, fieldType);
                 if (result != null) {
-                    map.put(additionalFieldPrefix + additionalField.getKey(), result);
+                    hasFields = writeIfNotEmpty(out, hasFields, additionalFieldPrefix + additionalField.getKey(), result);
                 }
             }
         }
 
-        return JSONValue.toJSONString(map);
+        JsonWriter.writeObjectEnd(out);
+    }
+
+    private boolean writeIfNotEmpty(OutputAccessor out, boolean hasFields, String field, Object value) {
+
+        if (value == null) {
+            return hasFields;
+        }
+
+        if (value instanceof String) {
+
+            if (isEmpty((String) value)) {
+                return hasFields;
+            }
+
+            if (hasFields) {
+                JsonWriter.writeKeyValueSeparator(out);
+            }
+
+            JsonWriter.writeMapEntry(out, field, value);
+
+            return true;
+        }
+
+        if (hasFields) {
+            JsonWriter.writeKeyValueSeparator(out);
+        }
+
+        JsonWriter.writeMapEntry(out, field, value);
+
+        return true;
     }
 
     /**
      * Get the field value as requested data type.
+     * 
      * @param value the value as string
      * @param fieldType see field types
      * @return the field value in the appropriate data type or {@literal null}.
@@ -210,7 +251,7 @@ public String toJson() {
     }
 
     public ByteBuffer[] toUDPBuffers() {
-        byte[] messageBytes = gzipMessage(toJson());
+        byte[] messageBytes = gzipMessage(toJsonByteArray("_"));
         // calculate the length of the datagrams array
         int diagrams_length = messageBytes.length / maximumMessageSize;
         // In case of a remainder, due to the integer division, add a extra datagram
@@ -229,16 +270,15 @@ public ByteBuffer[] toUDPBuffers() {
     }
 
     public ByteBuffer toTCPBuffer() {
-        byte[] messageBytes;
+
         // Do not use GZIP, as the headers will contain \0 bytes
         // graylog2-server uses \0 as a delimiter for TCP frames
         // see: https://github.com/Graylog2/graylog2-server/issues/127
-        String json = toJson();
-        json += '\0';
-        messageBytes = Charsets.utf8(json);
+        byte[] messageBytes = toJsonByteArray("_");
 
-        ByteBuffer buffer = ByteBuffer.allocate(messageBytes.length);
+        ByteBuffer buffer = ByteBuffer.allocate(messageBytes.length + 1);
         buffer.put(messageBytes);
+        buffer.put((byte) '\0');
         buffer.flip();
         return buffer;
     }
@@ -269,14 +309,13 @@ public int getCurrentMillis() {
         return (int) System.currentTimeMillis();
     }
 
-    private byte[] gzipMessage(String message) {
+    private byte[] gzipMessage(byte[] message) {
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
 
         try {
             GZIPOutputStream stream = new GZIPOutputStream(bos);
-            byte[] bytes = Charsets.utf8(message);
 
-            stream.write(bytes);
+            stream.write(message);
             stream.finish();
             Closer.close(stream);
             byte[] zipped = bos.toByteArray();
@@ -287,7 +326,7 @@ private byte[] gzipMessage(String message) {
         }
     }
 
-    private byte[] lastFourAsciiBytes(String host) {
+    private static byte[] lastFourAsciiBytes(String host) {
         final String shortHost = host.length() >= 4 ? host.substring(host.length() - 4) : host;
         return Charsets.ascii(shortHost);
     }