Issue #3681

Use LinkedHashMap<List<Pair>>

Signed-off-by: Greg Wilkins <gregw@webtide.com>

jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java

@@ -61,6 +61,11 @@ public class HttpFields implements Iterable<HttpField>
     private HttpField[] _fields;
     private int _size;
 
+
+    private int iterations = 0;
+    private int lookups;
+
+
     /**
      * Initialize an empty HttpFields.
      */
@@ -98,17 +103,20 @@ public class HttpFields implements Iterable<HttpField>
     @Override
     public Iterator<HttpField> iterator()
     {
+        iterations++;
         return new Itr();
     }
 
     public ListIterator<HttpField> listIterator()
     {
+        iterations++;
         return new Itr();
     }
     
     
     public Stream<HttpField> stream()
     {
+        iterations++;
         return StreamSupport.stream(Arrays.spliterator(_fields,0,_size),false);
     }
 
@@ -151,6 +159,7 @@ public class HttpFields implements Iterable<HttpField>
 
     public HttpField getField(HttpHeader header)
     {
+        lookups++;
         for (int i=0;i<_size;i++)
         {
             HttpField f=_fields[i];
@@ -162,6 +171,7 @@ public class HttpFields implements Iterable<HttpField>
 
     public HttpField getField(String name)
     {
+        lookups++;
         for (int i=0;i<_size;i++)
         {
             HttpField f=_fields[i];
@@ -173,6 +183,7 @@ public class HttpFields implements Iterable<HttpField>
 
     public boolean contains(HttpField field)
     {
+        lookups++;
         for (int i=_size;i-->0;)
         {
             HttpField f=_fields[i];
@@ -184,6 +195,7 @@ public class HttpFields implements Iterable<HttpField>
 
     public boolean contains(HttpHeader header, String value)
     {
+        lookups++;
         for (int i=_size;i-->0;)
         {
             HttpField f=_fields[i];
@@ -195,6 +207,7 @@ public class HttpFields implements Iterable<HttpField>
     
     public boolean contains(String name, String value)
     {
+        lookups++;
         for (int i=_size;i-->0;)
         {
             HttpField f=_fields[i];
@@ -206,6 +219,7 @@ public class HttpFields implements Iterable<HttpField>
 
     public boolean contains(HttpHeader header)
     {
+        lookups++;
         for (int i=_size;i-->0;)
         {
             HttpField f=_fields[i];
@@ -217,6 +231,7 @@ public class HttpFields implements Iterable<HttpField>
     
     public boolean containsKey(String name)
     {
+        lookups++;
         for (int i=_size;i-->0;)
         {
             HttpField f=_fields[i];
@@ -234,6 +249,7 @@ public class HttpFields implements Iterable<HttpField>
     
     public String get(HttpHeader header)
     {
+        lookups++;
         for (int i=0;i<_size;i++)
         {
             HttpField f=_fields[i];
@@ -251,6 +267,7 @@ public class HttpFields implements Iterable<HttpField>
     
     public String get(String header)
     {
+        lookups++;
         for (int i=0;i<_size;i++)
         {
             HttpField f=_fields[i];
@@ -268,6 +285,7 @@ public class HttpFields implements Iterable<HttpField>
      */
     public List<String> getValuesList(HttpHeader header)
     {
+        lookups++;
         final List<String> list = new ArrayList<>();
         for (HttpField f : this)
             if (f.getHeader()==header)
@@ -283,6 +301,7 @@ public class HttpFields implements Iterable<HttpField>
      */
     public List<String> getValuesList(String name)
     {
+        lookups++;
         final List<String> list = new ArrayList<>();
         for (HttpField f : this)
             if (f.getName().equalsIgnoreCase(name))
@@ -394,6 +413,7 @@ public class HttpFields implements Iterable<HttpField>
      */
     public List<String> getCSV(HttpHeader header,boolean keepQuotes)
     {
+        lookups++;
         QuotedCSV values = null;
         for (HttpField f : this)
         {
@@ -417,6 +437,7 @@ public class HttpFields implements Iterable<HttpField>
      */
     public List<String> getCSV(String name,boolean keepQuotes)
     {
+        lookups++;
         QuotedCSV values = null;
         for (HttpField f : this)
         {
@@ -903,6 +924,9 @@ public class HttpFields implements Iterable<HttpField>
 
     public void clear()
     {
+        System.err.printf("iterations=%d lookups=%d%n",iterations,lookups);
+        iterations = 0;
+        lookups = 0;
         _size=0;
     }
     

jetty-jmh/src/main/java/org/eclipse/jetty/server/jmh/ListVsMapBenchmark.java

@@ -20,14 +20,11 @@ package org.eclipse.jetty.server.jmh;
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
-import org.eclipse.jetty.util.ArrayTrie;
-import org.eclipse.jetty.util.TreeTrie;
-import org.eclipse.jetty.util.Trie;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.BenchmarkMode;
 import org.openjdk.jmh.annotations.Level;
@@ -48,7 +45,7 @@ import org.openjdk.jmh.runner.options.OptionsBuilder;
 @Threads(1)
 @Warmup(iterations = 6, time = 2000, timeUnit = TimeUnit.MILLISECONDS)
 @Measurement(iterations = 3, time = 2000, timeUnit = TimeUnit.MILLISECONDS)
-public class ListVsTrieBenchmark
+public class ListVsMapBenchmark
 {
     @Param({ "12" })   // Chrome has 12 for HTTP/1.1 and 16 for HTTP/2 (including meta headers)
     public static int size;
@@ -165,35 +162,28 @@ public class ListVsTrieBenchmark
 
     @Benchmark
     @BenchmarkMode({Mode.Throughput})
-    public long testTreeTrie() throws Exception
+    public long testSortedMap() throws Exception
     {
-        Trie<Pair> trie = new TreeTrie<>();
+        Map<String,List<Pair>> map = new LinkedHashMap<>(size);
-        fill(p->trie.put(p.key,p));
+        fill(p->
-        return test(trie::get);
+        {
-    }
+            List<Pair> list = new ArrayList<>();
-
+            list.add(p);
-    @Benchmark
+            map.put(p.key.toLowerCase(),list);
-    @BenchmarkMode({Mode.Throughput})
+        });
-    public long testArrayTrie() throws Exception
+        return test(k->
-    {
+        {
-        Trie<Pair> trie = new ArrayTrie<>(length*size);
+            List<Pair> list = map.get(k.toLowerCase());
-        fill(p->trie.put(p.key,p));
+            if (list==null || list.isEmpty())
-        return test(trie::get);
+                return null;
-    }
+            return list.get(0);
-
+        });
-    @Benchmark
-    @BenchmarkMode({Mode.Throughput})
-    public long testMap() throws Exception
-    {
-        Map<String,Pair> map = new HashMap<>(size);
-        fill(p->map.put(p.key.toLowerCase(),p));
-        return test(k->map.get(k.toLowerCase()));
     }
 
     public static void main(String[] args) throws RunnerException
     {
         Options opt = new OptionsBuilder()
-            .include(ListVsTrieBenchmark.class.getSimpleName())
+            .include(ListVsMapBenchmark.class.getSimpleName())
             // .addProfiler(GCProfiler.class)
             .forks(1)
             .build();