Use TreeMap to store headers

src/main/java/org/jsoup/helper/HttpConnection.java

@@ -43,15 +43,14 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Function;
+import java.util.TreeMap;
 import java.util.regex.Pattern;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.Inflater;
 import java.util.zip.InflaterInputStream;
 
 import static org.jsoup.Connection.Method.HEAD;
 import static org.jsoup.helper.DataUtil.UTF_8;
-import static org.jsoup.internal.Normalizer.lowerCase;
 
 /**
  * Implementation of {@link Connection}.
@@ -405,18 +404,18 @@ private static abstract class Base<T extends Connection.Base<T>> implements Conn
  Map<String, String> cookies;
 
  private Base() {
- headers = new LinkedHashMap<>();
+ headers = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
  cookies = new LinkedHashMap<>();
  }
 
  private Base(Base<T> copy) {
+ this();
  url = copy.url; // unmodifiable object
  method = copy.method;
- headers = new LinkedHashMap<>();
  for (Map.Entry<String, List<String>> entry : copy.headers.entrySet()) {
  headers.put(entry.getKey(), new ArrayList<>(entry.getValue()));
  }
- cookies = new LinkedHashMap<>(); cookies.putAll(copy.cookies); // just holds strings
+ cookies.putAll(copy.cookies); // just holds strings
  }
 
  @Override
@@ -448,8 +447,8 @@ public T method(Method method) {
  @Override
  public String header(String name) {
  Validate.notNullParam(name, "name");
- List<String> vals = getHeadersCaseInsensitive(name);
- if (vals.size() > 0) {
+ List<String> vals = headers.get(name);
+ if (vals != null) {
  // https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
  return StringUtil.join(vals, ", ");
  }
@@ -460,23 +459,17 @@ public String header(String name) {
  @Override
  public T addHeader(String name, @Nullable String value) {
  Validate.notEmptyParam(name, "name");
- //noinspection ConstantConditions
- value = value == null ? "" : value;
 
- List<String> values = headers(name);
- if (values.isEmpty()) {
- values = new ArrayList<>();
- headers.put(name, values);
- }
- values.add(value);
+ headers.computeIfAbsent(name, Functions.listFunction())
+ .add(value == null ? "" : value);
 
  return (T) this;
  }
 
  @Override
  public List<String> headers(String name) {
  Validate.notEmptyParam(name, "name");
- return getHeadersCaseInsensitive(name);
+ return headers.getOrDefault(name, Collections.emptyList());
  }
 
  @Override
@@ -490,7 +483,7 @@ public T header(String name, String value) {
  @Override
  public boolean hasHeader(String name) {
  Validate.notEmptyParam(name, "name");
- return !getHeadersCaseInsensitive(name).isEmpty();
+ return headers.containsKey(name);
  }
 
  /**
@@ -500,20 +493,14 @@ public boolean hasHeader(String name) {
  public boolean hasHeaderWithValue(String name, String value) {
  Validate.notEmpty(name);
  Validate.notEmpty(value);
- List<String> values = headers(name);
- for (String candidate : values) {
- if (value.equalsIgnoreCase(candidate))
- return true;
- }
- return false;
+ return headers.getOrDefault(name, Collections.emptyList()).stream()
+ .anyMatch(value::equalsIgnoreCase);
  }
 
  @Override
  public T removeHeader(String name) {
  Validate.notEmptyParam(name, "name");
- Map.Entry<String, List<String>> entry = scanHeaders(name); // remove is case-insensitive too
- if (entry != null)
- headers.remove(entry.getKey()); // ensures correct case
+ headers.remove(name); // remove is case-insensitive too
  return (T) this;
  }
 
@@ -534,26 +521,6 @@ public Map<String, List<String>> multiHeaders() {
  return headers;
  }
 
- private List<String> getHeadersCaseInsensitive(String name) {
- Validate.notNull(name);
-
- for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
- if (name.equalsIgnoreCase(entry.getKey()))
- return entry.getValue();
- }
-
- return Collections.emptyList();
- }
-
- private Map.@Nullable Entry<String, List<String>> scanHeaders(String name) {
- String lc = lowerCase(name);
- for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
- if (lowerCase(entry.getKey()).equals(lc))
- return entry;
- }
- return null;
- }
-
  @Override
  public String cookie(String name) {
  Validate.notEmptyParam(name, "name");