[ISSUE 3203] Replace the class 'StringBuffer' by 'StringBuilder' (#3204)

acl/src/main/java/org/apache/rocketmq/acl/plain/RemoteAddressStrategyFactory.java

@@ -167,7 +167,7 @@ public class RemoteAddressStrategyFactory {
                 String[] strArray = StringUtils.split(remoteAddr, ".");
                 if (analysis(strArray, 1) || analysis(strArray, 2) || analysis(strArray, 3)) {
                     AclUtils.verify(remoteAddr, index - 1);
-                    StringBuffer sb = new StringBuffer();
+                    StringBuilder sb = new StringBuilder();
                     for (int j = 0; j < index; j++) {
                         sb.append(strArray[j].trim()).append(".");
                     }

common/src/main/java/org/apache/rocketmq/common/UtilAll.java

@@ -565,11 +565,11 @@ public class UtilAll {
         if (list == null || list.size() == 0) {
             return null;
         }
-        StringBuffer str = new StringBuffer();
+        StringBuilder str = new StringBuilder();
         for (int i = 0; i < list.size(); i++) {
             str.append(list.get(i));
             if (i == list.size() - 1) {
-                continue;
+                break;
             }
             str.append(splitor);
         }

common/src/main/java/org/apache/rocketmq/common/message/Message.java

@@ -43,11 +43,13 @@ public class Message implements Serializable {
         this.flag = flag;
         this.body = body;
 
-        if (tags != null && tags.length() > 0)
+        if (tags != null && tags.length() > 0) {
             this.setTags(tags);
+        }
 
-        if (keys != null && keys.length() > 0)
+        if (keys != null && keys.length() > 0) {
             this.setKeys(keys);
+        }
 
         this.setWaitStoreMsgOK(waitStoreMsgOK);
     }
@@ -127,7 +129,7 @@ public class Message implements Serializable {
     }
 
     public void setKeys(Collection<String> keys) {
-        StringBuffer sb = new StringBuffer();
+        StringBuilder sb = new StringBuilder();
         for (String k : keys) {
             sb.append(k);
             sb.append(MessageConst.KEY_SEPARATOR);
@@ -151,8 +153,9 @@ public class Message implements Serializable {
 
     public boolean isWaitStoreMsgOK() {
         String result = this.getProperty(MessageConst.PROPERTY_WAIT_STORE_MSG_OK);
-        if (null == result)
+        if (null == result) {
             return true;
+        }
 
         return Boolean.parseBoolean(result);
     }

common/src/main/java/org/apache/rocketmq/common/protocol/NamespaceUtil.java

@@ -120,7 +120,7 @@ public class NamespaceUtil {
             return null;
         }
 
-        return new StringBuffer()
+        return new StringBuilder()
             .append(MixAll.RETRY_GROUP_TOPIC_PREFIX)
             .append(wrapNamespace(namespace, consumerGroup))
             .toString();

common/src/test/java/org/apache/rocketmq/common/UtilAllTest.java

@@ -19,11 +19,15 @@ package org.apache.rocketmq.common;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 import java.util.Properties;
 import org.junit.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.within;
+import static org.junit.Assert.assertEquals;
 
 public class UtilAllTest {
 
@@ -109,6 +113,15 @@ public class UtilAllTest {
         assertThat(UtilAll.ipToIPv6Str(nonInternal.getAddress()).toUpperCase()).isEqualTo("2408:4004:0180:8100:3FAA:1DDE:2B3F:898A");
     }
 
+    @Test
+    public void testList2String() {
+        List<String> list = Arrays.asList("groupA=DENY", "groupB=PUB|SUB", "groupC=SUB");
+        String comma = ",";
+        assertEquals("groupA=DENY,groupB=PUB|SUB,groupC=SUB", UtilAll.list2String(list, comma));
+        assertEquals(null, UtilAll.list2String(null, comma));
+        assertEquals(null, UtilAll.list2String(Collections.emptyList(), comma));
+    }
+
     static class DemoConfig {
         private int demoWidth = 0;
         private int demoLength = 0;

common/src/test/java/org/apache/rocketmq/common/utils/IOTinyUtilsTest.java

@@ -82,7 +82,7 @@ public class IOTinyUtilsTest {
 
     @Test
     public void testReadLines() throws Exception {
-        StringBuffer sb = new StringBuffer();
+        StringBuilder sb = new StringBuilder();
         for (int i = 0; i < 10; i++) {
             sb.append("testReadLines").append("\n");
         }
@@ -95,7 +95,7 @@ public class IOTinyUtilsTest {
 
     @Test
     public void testToBufferedReader() throws Exception {
-        StringBuffer sb = new StringBuffer();
+        StringBuilder sb = new StringBuilder();
         for (int i = 0; i < 10; i++) {
             sb.append("testToBufferedReader").append("\n");
         }

filter/src/main/java/org/apache/rocketmq/filter/expression/UnaryExpression.java

@@ -53,6 +53,7 @@ public abstract class UnaryExpression implements Expression {
 
     public static Expression createNegate(Expression left) {
         return new UnaryExpression(left, UnaryType.NEGATE) {
+            @Override
             public Object evaluate(EvaluationContext context) throws Exception {
                 Object rvalue = right.evaluate(context);
                 if (rvalue == null) {
@@ -64,6 +65,7 @@ public abstract class UnaryExpression implements Expression {
                 return null;
             }
 
+            @Override
             public String getExpressionSymbol() {
                 return "-";
             }
@@ -85,6 +87,7 @@ public abstract class UnaryExpression implements Expression {
         final Collection inList = t;
 
         return new UnaryInExpression(right, UnaryType.IN, inList, not) {
+            @Override
             public Object evaluate(EvaluationContext context) throws Exception {
 
                 Object rvalue = right.evaluate(context);
@@ -103,8 +106,9 @@ public abstract class UnaryExpression implements Expression {
 
             }
 
+            @Override
             public String toString() {
-                StringBuffer answer = new StringBuffer();
+                StringBuilder answer = new StringBuilder();
                 answer.append(right);
                 answer.append(" ");
                 answer.append(getExpressionSymbol());
@@ -124,6 +128,7 @@ public abstract class UnaryExpression implements Expression {
                 return answer.toString();
             }
 
+            @Override
             public String getExpressionSymbol() {
                 if (not) {
                     return "NOT IN";
@@ -139,6 +144,7 @@ public abstract class UnaryExpression implements Expression {
             super(left, unaryType);
         }
 
+        @Override
         public boolean matches(EvaluationContext context) throws Exception {
             Object object = evaluate(context);
             return object != null && object == Boolean.TRUE;
@@ -147,6 +153,7 @@ public abstract class UnaryExpression implements Expression {
 
     public static BooleanExpression createNOT(BooleanExpression left) {
         return new BooleanUnaryExpression(left, UnaryType.NOT) {
+            @Override
             public Object evaluate(EvaluationContext context) throws Exception {
                 Boolean lvalue = (Boolean) right.evaluate(context);
                 if (lvalue == null) {
@@ -155,6 +162,7 @@ public abstract class UnaryExpression implements Expression {
                 return lvalue.booleanValue() ? Boolean.FALSE : Boolean.TRUE;
             }
 
+            @Override
             public String getExpressionSymbol() {
                 return "NOT";
             }
@@ -163,6 +171,7 @@ public abstract class UnaryExpression implements Expression {
 
     public static BooleanExpression createBooleanCast(Expression left) {
         return new BooleanUnaryExpression(left, UnaryType.BOOLEANCAST) {
+            @Override
             public Object evaluate(EvaluationContext context) throws Exception {
                 Object rvalue = right.evaluate(context);
                 if (rvalue == null) {
@@ -174,10 +183,12 @@ public abstract class UnaryExpression implements Expression {
                 return ((Boolean) rvalue).booleanValue() ? Boolean.TRUE : Boolean.FALSE;
             }
 
+            @Override
             public String toString() {
                 return right.toString();
             }
 
+            @Override
             public String getExpressionSymbol() {
                 return "";
             }
@@ -233,6 +244,7 @@ public abstract class UnaryExpression implements Expression {
     /**
      * @see Object#toString()
      */
+    @Override
     public String toString() {
         return "(" + getExpressionSymbol() + " " + right.toString() + ")";
     }
@@ -240,6 +252,7 @@ public abstract class UnaryExpression implements Expression {
     /**
      * @see Object#hashCode()
      */
+    @Override
     public int hashCode() {
         return toString().hashCode();
     }
@@ -247,6 +260,7 @@ public abstract class UnaryExpression implements Expression {
     /**
      * @see Object#equals(Object)
      */
+    @Override
     public boolean equals(Object o) {
 
         if (o == null || !this.getClass().equals(o.getClass())) {

filter/src/main/java/org/apache/rocketmq/filter/parser/ParseException.java

@@ -106,7 +106,7 @@ public class ParseException extends Exception {
         int[][] expectedTokenSequences,
         String[] tokenImage) {
         String eol = System.getProperty("line.separator", "\n");
-        StringBuffer expected = new StringBuffer();
+        StringBuilder expected = new StringBuilder();
         int maxSize = 0;
         for (int i = 0; i < expectedTokenSequences.length; i++) {
             if (maxSize < expectedTokenSequences[i].length) {
@@ -123,8 +123,9 @@ public class ParseException extends Exception {
         String retval = "Encountered \"";
         Token tok = currentToken.next;
         for (int i = 0; i < maxSize; i++) {
-            if (i != 0)
+            if (i != 0) {
                 retval += " ";
+            }
             if (tok.kind == 0) {
                 retval += tokenImage[0];
                 break;
@@ -157,7 +158,7 @@ public class ParseException extends Exception {
      * string literal.
      */
     static String add_escapes(String str) {
-        StringBuffer retval = new StringBuffer();
+        StringBuilder retval = new StringBuilder();
         char ch;
         for (int i = 0; i < str.length(); i++) {
             switch (str.charAt(i)) {

filter/src/main/java/org/apache/rocketmq/filter/parser/TokenMgrError.java

@@ -66,7 +66,7 @@ public class TokenMgrError extends Error {
      * equivalents in the given string
      */
     protected static final String addEscapes(String str) {
-        StringBuffer retval = new StringBuffer();
+        StringBuilder retval = new StringBuilder();
         char ch;
         for (int i = 0; i < str.length(); i++) {
             switch (str.charAt(i)) {
@@ -141,6 +141,7 @@ public class TokenMgrError extends Error {
      * <p/>
      * from this method for such cases in the release version of your parser.
      */
+    @Override
     public String getMessage() {
         return super.getMessage();
     }

filter/src/test/java/org/apache/rocketmq/filter/ParserTest.java

@@ -84,7 +84,7 @@ public class ParserTest {
     @Test
     public void testParse_floatOverFlow() {
         try {
-            StringBuffer sb = new StringBuffer(210000);
+            StringBuilder sb = new StringBuilder(210000);
             sb.append("1");
             for (int i = 0; i < 2048; i ++) {
                 sb.append("111111111111111111111111111111111111111111111111111");

remoting/src/main/java/org/apache/rocketmq/remoting/common/RemotingHelper.java

@@ -36,7 +36,7 @@ public class RemotingHelper {
     private static final InternalLogger log = InternalLoggerFactory.getLogger(ROCKETMQ_REMOTING);
 
     public static String exceptionSimpleDesc(final Throwable e) {
-        StringBuffer sb = new StringBuffer();
+        StringBuilder sb = new StringBuilder();
         if (e != null) {
             sb.append(e.toString());
 

store/src/main/java/org/apache/rocketmq/store/stats/BrokerStatsManager.java

@@ -159,7 +159,7 @@ public class BrokerStatsManager {
     }
 
     public String buildStatsKey(String topic, String group) {
-        StringBuffer strBuilder = new StringBuffer();
+        StringBuilder strBuilder = new StringBuilder();
         strBuilder.append(topic);
         strBuilder.append("@");
         strBuilder.append(group);
@@ -217,7 +217,7 @@ public class BrokerStatsManager {
     }
 
     public String buildCommercialStatsKey(String owner, String topic, String group, String type) {
-        StringBuffer strBuilder = new StringBuffer();
+        StringBuilder strBuilder = new StringBuilder();
         strBuilder.append(owner);
         strBuilder.append("@");
         strBuilder.append(topic);

tools/src/main/java/org/apache/rocketmq/tools/command/message/QueryMsgByUniqueKeySubCommand.java

@@ -114,7 +114,7 @@ public class QueryMsgByUniqueKeySubCommand implements SubCommand {
     private static String createBodyFile(MessageExt msg, int index) throws IOException {
         DataOutputStream dos = null;
         try {
-            StringBuffer bodyTmpFilePath = new StringBuffer("/tmp/rocketmq/msgbodys");
+            StringBuilder bodyTmpFilePath = new StringBuilder("/tmp/rocketmq/msgbodys");
             File file = new File(bodyTmpFilePath.toString());
             if (!file.exists()) {
                 file.mkdirs();
@@ -127,8 +127,9 @@ public class QueryMsgByUniqueKeySubCommand implements SubCommand {
             dos.write(msg.getBody());
             return bodyTmpFilePath.toString();
         } finally {
-            if (dos != null)
+            if (dos != null) {
                 dos.close();
+            }
         }
     }