性能优化：解析器StringBuilder复用

Author: Qieqie

paoding-rose-jade/src/main/java/net/paoding/rose/jade/statement/SystemInterpreter.java

@@ -32,7 +32,7 @@
  * @author 廖涵 [in355hz@gmail.com]
  */
 public class SystemInterpreter implements Interpreter {
-
+    
     private ReplacementInterpreter     replacementInterpreter     = new ReplacementInterpreter();
     private PreparestatmentInterpreter preparestatmentInterpreter = new PreparestatmentInterpreter();
 
@@ -54,14 +54,24 @@ static class ReplacementInterpreter implements Interpreter {
 
         final Pattern PATTERN = Pattern.compile("\\{([a-zA-Z0-9_\\.\\:]+)\\}|##\\((.+)\\)");
 
+
+        final ThreadLocal<StringBuilder> stringBuilderPool = new ThreadLocal<StringBuilder>(){
+            @Override
+            public StringBuilder initialValue() {
+                return new StringBuilder();
+            };
+            
+        };
+
         @Override
         public void interpret(StatementRuntime runtime) {// ##(:xxx)
+            StringBuilder sqlResult = stringBuilderPool.get();
+            sqlResult.setLength(0);
             String sql = runtime.getSQL();
-            StringBuilder sb = new StringBuilder(sql.length() + 200);
             Matcher matcher = PATTERN.matcher(sql);
             int start = 0;
             while (matcher.find(start)) {
-                sb.append(sql.substring(start, matcher.start()));
+                sqlResult.append(sql.substring(start, matcher.start()));
                 String group = matcher.group(); 
                 String key = null;
                 if (group.startsWith("{")) {
@@ -95,29 +105,39 @@ public void interpret(StatementRuntime runtime) {// ##(:xxx)
                 }
                 // replace it
                 if (value != null) {
-                    sb.append(value);
+                    sqlResult.append(value);
                 } else {
-                    sb.append(group);
+                    sqlResult.append(group);
                 }
                 start = matcher.end();
             }
-            sb.append(sql.substring(start));
+            sqlResult.append(sql.substring(start));
 
-            runtime.setSQL(sb.toString());
+            runtime.setSQL(sqlResult.toString());
 
         }
     }
 
     // 动态参数
     static class PreparestatmentInterpreter implements Interpreter {
 
+
+        static final ThreadLocal<ExqlContextImpl> exqlContextPool = new ThreadLocal<ExqlContextImpl>(){
+            @Override
+            public ExqlContextImpl initialValue() {
+                return new ExqlContextImpl();
+            };
+            
+        };
+        
         @Override
         public void interpret(StatementRuntime runtime) {
             // 转换语句中的表达式
-            ExqlPattern pattern = ExqlPatternImpl.compile(runtime.getSQL());
-            ExqlContextImpl context = new ExqlContextImpl(runtime.getSQL().length() + 32);
+            ExqlContextImpl context = exqlContextPool.get();
+            context.clear();
 
             try {
+                ExqlPattern pattern = ExqlPatternImpl.compile(runtime.getSQL());
                 Map<String, Object> constants = runtime.getMetaData().getDAOMetaData()
                     .getConstants();
                 pattern.execute(context, runtime.getParameters(), constants);
@@ -192,7 +212,7 @@ public static void main0(String[] args) throws Exception {
                      + "(`id`,`uid`,`favable_id`,`addtime`,`ranking`) "//
                      + "values (:1,:2,now(),0)";
         ExqlPattern pattern = ExqlPatternImpl.compile(sql);
-        ExqlContextImpl context = new ExqlContextImpl(sql.length() + 32);
+        ExqlContextImpl context = new ExqlContextImpl();
 
         Map<String, Object> parametersAsMap = new HashMap<String, Object>();
         parametersAsMap.put(":1", "p1");

paoding-rose-jade/src/main/java/net/paoding/rose/jade/statement/expression/impl/ExqlCompiler.java

@@ -481,7 +481,7 @@ public static void main(String... args) throws Exception {
         // 编译下列语句
         ExqlPattern pattern = new ExqlCompiler(string).compile();
 
-        ExqlContext context = new ExqlContextImpl(string.length());
+        ExqlContext context = new ExqlContextImpl();
 
         HashMap<String, Object> map = new HashMap<String, Object>();
 

paoding-rose-jade/src/main/java/net/paoding/rose/jade/statement/expression/impl/ExqlContextImpl.java

@@ -26,15 +26,22 @@ public class ExqlContextImpl implements ExqlContext  {
     protected final ArrayList<Object> args = new ArrayList<Object>();
 
     // 输出缓冲区
-    protected final StringBuilder builder;
+    protected final StringBuilder builder = new StringBuilder(256);
 
     /**
      * 构造上下文对象。
      * 
      * @param capacity - 缓存的容量
      */
-    public ExqlContextImpl(int capacity) {
-        builder = new StringBuilder(capacity);
+    public ExqlContextImpl() {
+    }
+
+    /**
+     * 清理以便下次使用
+     */
+    public void clear() {
+        this.args.clear();
+        this.builder.setLength(0);
     }
 
     @Override
@@ -144,7 +151,7 @@ private void fillCollection(Collection<?> collection) {
     // 进行简单测试
     public static void main(String... args) throws Exception {
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         context.fillText("WHERE uid = ");
         context.fillValue(102);

paoding-rose-jade/src/main/java/net/paoding/rose/jade/statement/expression/impl/ExqlPatternImpl.java

@@ -114,7 +114,7 @@ public static void main(String... args) throws Exception {
                         + "#for(variant in :expr5.bytes) { AND c = :variant}" // NL
                         + " GROUP BY #!(:expr1) ASC {expr3}");
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         HashMap<String, Object> map = new HashMap<String, Object>();
 

paoding-rose-jade/src/test/java/net/paoding/rose/jade/exql/ExqlContextTests.java

@@ -13,7 +13,7 @@ public void testExqlContext() {
 
         Date current = new Date();
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         context.fillText("WHERE uid = ");
         context.fillValue(102);

paoding-rose-jade/src/test/java/net/paoding/rose/jade/exql/ExqlPatternTests.java

@@ -39,7 +39,7 @@ public void testPattern() throws Exception {
                                               expr5.getBytes()[4], expr1 };
 
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         HashMap<String, Object> map = new HashMap<String, Object>();
 
@@ -77,7 +77,7 @@ public void testConstant() throws Exception {
                         + "#for(variant in $expr5.bytes) { AND c = :variant}" // NL
                         + " GROUP BY $expr1 ASC");
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         HashMap<String, Object> map = new HashMap<String, Object>();
 
@@ -118,7 +118,7 @@ public void testComplex() throws Exception {
                         + "#for(variant in $expr5.bytes) { AND c = :variant}" // NL
                         + " GROUP BY $expr1 ASC");
 
-        ExqlContext context = new ExqlContextImpl(1024);
+        ExqlContext context = new ExqlContextImpl();
 
         HashMap<String, Object> map = new HashMap<String, Object>();