Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / AttributesMap.java

diff --git a/lib/jetty/org/eclipse/jetty/util/AttributesMap.java b/lib/jetty/org/eclipse/jetty/util/AttributesMap.java
new file mode 100644 (file)
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+++ b/lib/jetty/org/eclipse/jetty/util/AttributesMap.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicReference;
+
+public class AttributesMap implements Attributes
+{
+    private final AtomicReference<ConcurrentMap<String, Object>> _map = new AtomicReference<>();
+
+    public AttributesMap()
+    {
+    }
+
+    public AttributesMap(AttributesMap attributes)
+    {
+        ConcurrentMap<String, Object> map = attributes.map();
+        if (map != null)
+            _map.set(new ConcurrentHashMap<>(map));
+    }
+
+    private ConcurrentMap<String, Object> map()
+    {
+        return _map.get();
+    }
+
+    private ConcurrentMap<String, Object> ensureMap()
+    {
+        while (true)
+        {
+            ConcurrentMap<String, Object> map = map();
+            if (map != null)
+                return map;
+            map = new ConcurrentHashMap<>();
+            if (_map.compareAndSet(null, map))
+                return map;
+        }
+    }
+
+    @Override
+    public void removeAttribute(String name)
+    {
+        Map<String, Object> map = map();
+        if (map != null)
+            map.remove(name);
+    }
+
+    @Override
+    public void setAttribute(String name, Object attribute)
+    {
+        if (attribute == null)
+            removeAttribute(name);
+        else
+            ensureMap().put(name, attribute);
+    }
+
+    @Override
+    public Object getAttribute(String name)
+    {
+        Map<String, Object> map = map();
+        return map == null ? null : map.get(name);
+    }
+
+    @Override
+    public Enumeration<String> getAttributeNames()
+    {
+        return Collections.enumeration(getAttributeNameSet());
+    }
+
+    public Set<String> getAttributeNameSet()
+    {
+        return keySet();
+    }
+
+    public Set<Map.Entry<String, Object>> getAttributeEntrySet()
+    {
+        Map<String, Object> map = map();
+        return map == null ? Collections.<Map.Entry<String, Object>>emptySet() : map.entrySet();
+    }
+
+    public static Enumeration<String> getAttributeNamesCopy(Attributes attrs)
+    {
+        if (attrs instanceof AttributesMap)
+            return Collections.enumeration(((AttributesMap)attrs).keySet());
+
+        List<String> names = new ArrayList<>();
+        names.addAll(Collections.list(attrs.getAttributeNames()));
+        return Collections.enumeration(names);
+    }
+
+    @Override
+    public void clearAttributes()
+    {
+        Map<String, Object> map = map();
+        if (map != null)
+            map.clear();
+    }
+
+    public int size()
+    {
+        Map<String, Object> map = map();
+        return map == null ? 0 : map.size();
+    }
+
+    @Override
+    public String toString()
+    {
+        Map<String, Object> map = map();
+        return map == null ? "{}" : map.toString();
+    }
+
+    private Set<String> keySet()
+    {
+        Map<String, Object> map = map();
+        return map == null ? Collections.<String>emptySet() : map.keySet();
+    }
+
+    public void addAll(Attributes attributes)
+    {
+        Enumeration<String> e = attributes.getAttributeNames();
+        while (e.hasMoreElements())
+        {
+            String name = e.nextElement();
+            setAttribute(name, attributes.getAttribute(name));
+        }
+    }
+}