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From hls...@apache.org
Subject svn commit: r1094823 - in /tapestry/tapestry5/trunk/tapestry-core/src: main/java/org/apache/tapestry5/internal/util/NamedSet.java test/groovy/org/apache/tapestry5/internal/util/ test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy
Date Tue, 19 Apr 2011 00:18:20 GMT
Author: hlship
Date: Tue Apr 19 00:18:20 2011
New Revision: 1094823

URL: http://svn.apache.org/viewvc?rev=1094823&view=rev
Log:
TAP5-1508: Add a simple and (hopefully) efficient NamedSet

Added:
    tapestry/tapestry5/trunk/tapestry-core/src/main/java/org/apache/tapestry5/internal/util/NamedSet.java
    tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/
    tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy

Added: tapestry/tapestry5/trunk/tapestry-core/src/main/java/org/apache/tapestry5/internal/util/NamedSet.java
URL: http://svn.apache.org/viewvc/tapestry/tapestry5/trunk/tapestry-core/src/main/java/org/apache/tapestry5/internal/util/NamedSet.java?rev=1094823&view=auto
==============================================================================
--- tapestry/tapestry5/trunk/tapestry-core/src/main/java/org/apache/tapestry5/internal/util/NamedSet.java
(added)
+++ tapestry/tapestry5/trunk/tapestry-core/src/main/java/org/apache/tapestry5/internal/util/NamedSet.java
Tue Apr 19 00:18:20 2011
@@ -0,0 +1,133 @@
+// Copyright 2011 The Apache Software Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package org.apache.tapestry5.internal.util;
+
+import java.util.Set;
+
+import org.apache.commons.collections.map.CaseInsensitiveMap;
+import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
+import org.apache.tapestry5.ioc.internal.util.InternalUtils;
+
+/**
+ * Simple, thread-safe associative array that relates a name to a value. Names are case-insensitive.
+ * This is optimized to use less memory (than a {@link CaseInsensitiveMap} (it uses a singly-liked
list),
+ * though the cost of a lookup is more expensive. However, this is a good match against many
of the structures inside
+ * a page instance, where most lookups occur only during page constructions, and the number
of values is often small.
+ * <p>
+ * We use simply synchronization, as uncontested synchronized locks are very, very cheap.
+ * 
+ * @param <T>
+ *            the type of value stored
+ */
+public class NamedSet<T>
+{
+    private NamedRef<T> first;
+
+    private static class NamedRef<T>
+    {
+        NamedRef<T> next;
+
+        String name;
+
+        T value;
+
+        public NamedRef(String name, T value)
+        {
+            this.name = name;
+            this.value = value;
+        }
+    }
+
+    /**
+     * Returns a set of the names of all stored values.
+     */
+    public synchronized Set<String> getNames()
+    {
+        Set<String> result = CollectionFactory.newSet();
+
+        NamedRef<T> cursor = first;
+
+        while (cursor != null)
+        {
+            result.add(cursor.name);
+            cursor = cursor.next;
+        }
+
+        return result;
+    }
+
+    /**
+     * Gets the value for the provided name.
+     * 
+     * @param name
+     *            used to locate the value
+     * @return the value, or null if not found
+     */
+    public synchronized T get(String name)
+    {
+        NamedRef<T> cursor = first;
+
+        while (cursor != null)
+        {
+            if (cursor.name.equalsIgnoreCase(name)) { return cursor.value; }
+
+            cursor = cursor.next;
+        }
+
+        return null;
+    }
+
+    /**
+     * Stores a new value into the set, replacing any previous value with the same name.
Name comparisons are case
+     * insensitive.
+     * 
+     * @param name
+     *            to store the value. May not be blank.
+     * @param newValue
+     *            non-null value to store
+     */
+    public synchronized void put(String name, T newValue)
+    {
+        assert InternalUtils.isNonBlank(name);
+        assert newValue != null;
+
+        NamedRef<T> prev = null;
+        NamedRef<T> cursor = first;
+
+        while (cursor != null)
+        {
+            if (cursor.name.equalsIgnoreCase(name))
+            {
+                // Retain the case of the name as put(), even if it doesn't match
+                // the existing case
+
+                cursor.name = name;
+                cursor.value = newValue;
+
+                return;
+            }
+
+            prev = cursor;
+            cursor = cursor.next;
+        }
+
+        NamedRef<T> newRef = new NamedRef<T>(name, newValue);
+
+        if (prev == null)
+            first = newRef;
+        else
+            prev.next = newRef;
+    }
+}

Added: tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy
URL: http://svn.apache.org/viewvc/tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy?rev=1094823&view=auto
==============================================================================
--- tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy
(added)
+++ tapestry/tapestry5/trunk/tapestry-core/src/test/groovy/org/apache/tapestry5/internal/util/NamedSetTests.groovy
Tue Apr 19 00:18:20 2011
@@ -0,0 +1,66 @@
+// Copyright 2011 The Apache Software Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package org.apache.tapestry5.internal.util
+
+import org.testng.Assert
+import org.testng.annotations.Test
+
+class NamedSetTests extends Assert
+{
+    @Test
+    void empty_set_yields_rempty_names() {
+        assert new NamedSet().names.empty
+    }
+
+    @Test
+    void stored_names_retain_case() {
+        NamedSet ns = new NamedSet()
+
+        ns.put "Fred", 100
+        ns.put "Barney", 200
+
+        assert ns.get("fred") == 100
+        assert ns.get("barney") == 200
+
+        assert ns.names.sort() == ["Barney", "Fred"]
+    }
+
+    @Test
+    void replace_a_named_value() {
+        NamedSet ns = new NamedSet()
+
+        ns.put "Fred", 100
+        ns.put "Barney", 200
+
+        assert ns.get("fred") == 100
+        assert ns.get("barney") == 200
+
+        ns.put "FRED", 110
+        ns.put "barNEY", 120
+
+        assert ns.get("fred") == 110
+        assert ns.get("barney") == 120
+
+        assert ns.names.sort() == ["FRED", "barNEY"]
+    }
+
+    @Test
+    void missing_key_returns_null() {
+        NamedSet ns = new NamedSet()
+
+
+        assert ns.get("anything") == null
+    }
+}



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