[exo-jcr-commits] exo-jcr SVN: r4588 - kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache and 3 other directories.
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Mon Jul 4 13:12:39 EDT 2011
Author: nfilotto
Date: 2011-07-04 13:12:39 -0400 (Mon, 04 Jul 2011)
New Revision: 4588
Added:
kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/
kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureCache.java
kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureExoCache.java
kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/Loader.java
kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/
kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/ConcurrentGetWhenPutTestCase.java
kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/FutureMap.java
kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/GetTestCase.java
kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/StringLoader.java
Modified:
jcr/trunk/exo.jcr.docs/exo.jcr.docs.developer/en/src/main/docbook/en-US/modules/kernel/cache.xml
Log:
EXOJCR-1419: Move FutureExoCache from GateIn commons to eXo kernel
Modified: jcr/trunk/exo.jcr.docs/exo.jcr.docs.developer/en/src/main/docbook/en-US/modules/kernel/cache.xml
===================================================================
--- jcr/trunk/exo.jcr.docs/exo.jcr.docs.developer/en/src/main/docbook/en-US/modules/kernel/cache.xml 2011-07-04 12:56:27 UTC (rev 4587)
+++ jcr/trunk/exo.jcr.docs/exo.jcr.docs.developer/en/src/main/docbook/en-US/modules/kernel/cache.xml 2011-07-04 17:12:39 UTC (rev 4588)
@@ -133,7 +133,7 @@
<entry>replicated</entry>
<entry>Indicates if the cache is replicated. This field is
- optional. </entry>
+ optional.</entry>
</row>
<row>
@@ -231,6 +231,36 @@
the infinite loop described above will still be effective.</para>
</note>
</section>
+
+ <section>
+ <title>FutureExoCache</title>
+
+ <para>If the data that you want to store into your eXo Cache instance
+ and/or you would like to prevent multiple concurrent loading of the same
+ data at the same time, you can use
+ <emphasis>org.exoplatform.services.cache.future.FutureExoCache</emphasis>
+ on top of your eXo Cache instance in order to delegate the loading of
+ your data to a loader that will be called only once whatever the total
+ amount of concurrent thread looking for it. See below an example of how
+ the FutureExoCache can be used:</para>
+
+ <programlisting language="java">import org.exoplatform.services.cache.future.Loader;
+import org.exoplatform.services.cache.future.FutureExoCache;
+...
+ // Define first your loader and choose properly your context object in order
+ // to be able to reuse the same loader for different FutureExoCache instances
+ Loader<String, String, String> loader = new Loader<String, String, String>()
+ {
+ public String retrieve(String context, String key) throws Exception
+ {
+ return "Value loaded thanks to the key = '" + key + "' and the context = '" + context + "'";
+ }
+ };
+ // Create your FutureExoCache from your eXo cache instance and your loader
+ FutureExoCache<String, String, String> myFutureExoCache = new FutureExoCache<String, String, String>(loader, myExoCache);
+ // Get your data from your future cache instance
+ System.out.println(myFutureExoCache.get("my context", "foo"));</programlisting>
+ </section>
</section>
<section>
Added: kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureCache.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureCache.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureCache.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import org.exoplatform.services.log.ExoLogger;
+import org.exoplatform.services.log.Log;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.FutureTask;
+
+/**
+ * A future cache that prevents the loading of the same resource twice. This should be used when the resource
+ * to load is very expensive or cannot be concurrently retrieved (like a classloading).
+ *
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ * @param <K> the key type parameter
+ * @param <V> the value type parameter
+ * @param <C> the context type parameter
+ */
+public abstract class FutureCache<K, V, C>
+{
+
+ /** . */
+ private final Loader<K, V, C> loader;
+
+ /** . */
+ private final ConcurrentMap<K, FutureTask<V>> futureEntries;
+
+ /** . */
+ private static final Log log = ExoLogger.getLogger("exo.kernel.component.cache.FutureCache");
+
+
+ public FutureCache(Loader<K, V, C> loader)
+ {
+ this.loader = loader;
+ this.futureEntries = new ConcurrentHashMap<K, FutureTask<V>>();
+ }
+
+ protected abstract V get(K key);
+
+ protected abstract void put(K key, V value);
+
+ /**
+ * Perform a cache lookup for the specified key within the specified context.
+ * When the value cannot be loaded (because it does not exist or it failed or anything else that
+ * does not come to my mind), the value null is returned.
+ *
+ * @param context the context in which the resource is accessed
+ * @param key the key identifying the resource
+ * @return the value
+ */
+ public final V get(final C context, final K key)
+ {
+ // First we try a simple cache get
+ V value = get(key);
+
+ // If it does not succeed then we go through a process that will avoid to load
+ // the same resource concurrently
+ if (value == null)
+ {
+ // Create our future
+ FutureTask<V> future = new FutureTask<V>(new Callable<V>()
+ {
+ public V call() throws Exception
+ {
+ // Retrieve the value from the loader
+ V value = loader.retrieve(context, key);
+
+ //
+ if (value != null)
+ {
+ // Cache it, it is made available to other threads (unless someone removes it)
+ put(key, value);
+
+ // Return value
+ return value;
+ }
+ else
+ {
+ return null;
+ }
+ }
+ });
+
+ // This boolean means we inserted in the local
+ boolean inserted = true;
+
+ //
+ try
+ {
+ FutureTask<V> phantom = futureEntries.putIfAbsent(key, future);
+
+ // Use the value that could have been inserted by another thread
+ if (phantom != null)
+ {
+ future = phantom;
+ inserted = false;
+ }
+ else
+ {
+ future.run();
+ }
+
+ // Returns the value
+ value = future.get();
+ }
+ catch (ExecutionException e)
+ {
+ log.error("Computing of resource " + key + " threw an exception", e.getCause());
+ }
+ catch (Exception e)
+ {
+ log.error("Retrieval of resource " + key + " threw an exception", e);
+ }
+ finally
+ {
+ // Clean up the per key map but only if our insertion succeeded and with our future
+ if (inserted)
+ {
+ futureEntries.remove(key, future);
+ }
+ }
+ }
+
+ //
+ return value;
+ }
+}
Added: kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureExoCache.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureExoCache.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/FutureExoCache.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import org.exoplatform.services.cache.ExoCache;
+
+import java.io.Serializable;
+
+/**
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ */
+public class FutureExoCache<K extends Serializable, V, C> extends FutureCache<K, V, C>
+{
+
+ /** . */
+ private final ExoCache<K, V> cache;
+
+ public FutureExoCache(Loader<K, V, C> loader, ExoCache<K, V> cache)
+ {
+ super(loader);
+
+ //
+ this.cache = cache;
+ }
+
+ @Override
+ protected V get(K key)
+ {
+ return cache.get(key);
+ }
+
+ @Override
+ protected void put(K key, V entry)
+ {
+ cache.put(key, entry);
+ }
+}
+
Added: kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/Loader.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/Loader.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/main/java/org/exoplatform/services/cache/future/Loader.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+/**
+ * The loader interface is used by the future cache to retrieves the value from the key when it does not exist.
+ *
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ * @param <K> the key type parameter
+ * @param <V> the value type parameter
+ * @param <C> the context type parameter
+ */
+public interface Loader<K, V, C>
+{
+
+ /**
+ * Retrieves the value from the key within the specified context. If the resource is not found then the value
+ * null must be returned.
+ *
+ * @param context the context
+ * @param key the key
+ * @return the value
+ * @throws Exception any exception that would prevent the value to be loaded
+ */
+ V retrieve(C context, K key) throws Exception;
+
+}
Added: kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/ConcurrentGetWhenPutTestCase.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/ConcurrentGetWhenPutTestCase.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/ConcurrentGetWhenPutTestCase.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import junit.framework.AssertionFailedError;
+import junit.framework.TestCase;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.Callable;
+
+/**
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ */
+public class ConcurrentGetWhenPutTestCase extends TestCase
+{
+
+ /** . */
+ private AssertionFailedError failure;
+
+ /** . */
+ private List<String> events = Collections.synchronizedList(new LinkedList<String>());
+
+ FutureCache<String, String, Callable<String>> futureCache = new FutureCache<String, String, Callable<String>>(new StringLoader()) {
+
+
+ @Override
+ protected String get(String key)
+ {
+ if (key == key1)
+ {
+ if (Thread.currentThread() != thread1)
+ {
+ failure = new AssertionFailedError();
+ }
+ events.add("get/key1");
+ }
+ else if (key == key2)
+ {
+ if (Thread.currentThread() != thread2)
+ {
+ failure = new AssertionFailedError();
+ }
+ events.add("get/key2");
+ }
+ else
+ {
+ failure = new AssertionFailedError();
+ }
+ return null;
+ }
+
+ @Override
+ protected void put(String key, String value)
+ {
+ if (key == key1)
+ {
+ if (Thread.currentThread() == thread1)
+ {
+ events.add("begin_put/key1/" + value);
+
+ //
+ thread2.start();
+
+ //
+ while (thread2.getState() != Thread.State.WAITING)
+ {
+ // Wait until thread 2 is blocked
+ }
+
+ //
+ events.add("end_put/key1");
+ }
+ else
+ {
+ failure = new AssertionFailedError();
+ }
+ }
+ else
+ {
+ failure = new AssertionFailedError();
+ }
+ }
+ };
+
+ /** . */
+ private final String key1 = new String("foo");
+
+ /** . */
+ private final String key2 = new String("foo");
+
+ Thread thread1 = new Thread()
+ {
+ @Override
+ public void run()
+ {
+ String v = futureCache.get(new Callable<String>()
+ {
+ public String call() throws Exception
+ {
+ events.add("call/key1");
+ return "foo_value_1";
+ }
+ }, key1);
+ events.add("retrieved/key1/" + v);
+ }
+ };
+
+ Thread thread2 = new Thread()
+ {
+ @Override
+ public void run()
+ {
+ String v = futureCache.get(new Callable<String>()
+ {
+ public String call() throws Exception
+ {
+ failure = new AssertionFailedError();
+ return "foo_value_2";
+ }
+ }, key2);
+ events.add("retrieved/key2/" + v);
+ }
+ };
+
+ public void testMain() throws Exception
+ {
+ thread1.start();
+
+ //
+ thread1.join();
+ thread2.join();
+
+ //
+ if (failure != null)
+ {
+ throw failure;
+ }
+
+ //
+ List<String> expectedEvents = Arrays.asList(
+ "get/key1",
+ "call/key1",
+ "begin_put/key1/foo_value_1",
+ "get/key2",
+ "end_put/key1"
+ );
+
+ //
+ assertEquals(expectedEvents, events.subList(0, expectedEvents.size()));
+
+ //
+ Set<String> expectedEndEvents = new HashSet<String>(Arrays.asList("retrieved/key1/foo_value_1", "retrieved/key2/foo_value_1"));
+ assertEquals(expectedEndEvents, new HashSet<String>(events.subList(expectedEvents.size(), events.size())));
+ }
+}
\ No newline at end of file
Added: kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/FutureMap.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/FutureMap.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/FutureMap.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ */
+public class FutureMap<C> extends FutureCache<String, String, C>
+{
+
+ /** . */
+ final Map<String, String> data;
+
+ public FutureMap(Loader<String, String, C> loader)
+ {
+ super(loader);
+
+ //
+ this.data = Collections.synchronizedMap(new HashMap<String, String>());
+ }
+
+ @Override
+ protected String get(String key)
+ {
+ return data.get(key);
+ }
+
+ @Override
+ protected void put(String key, String value)
+ {
+ data.put(key, value);
+ }
+}
Added: kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/GetTestCase.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/GetTestCase.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/GetTestCase.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import java.util.concurrent.Callable;
+
+/**
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ */
+public class GetTestCase extends TestCase
+{
+ public void testGet()
+ {
+ FutureMap<Callable<String>> futureCache = new FutureMap<Callable<String>>(new StringLoader());
+ Assert.assertEquals("foo_value", futureCache.get(new Callable<String>()
+ {
+ public String call() throws Exception
+ {
+ return "foo_value";
+ }
+ }, "foo"));
+ Assert.assertEquals("foo_value", futureCache.data.get("foo"));
+ }
+
+ public void testNullValue()
+ {
+ FutureMap<Callable<String>> futureCache = new FutureMap<Callable<String>>(new StringLoader());
+ Assert.assertEquals(null, futureCache.get(new Callable<String>()
+ {
+ public String call() throws Exception
+ {
+ return null;
+ }
+ }, "foo"));
+ Assert.assertFalse(futureCache.data.containsKey("foo"));
+ }
+
+ public void testThrowException()
+ {
+ FutureMap<Callable<String>> futureCache = new FutureMap<Callable<String>>(new StringLoader());
+ Assert.assertEquals(null, futureCache.get(new Callable<String>()
+ {
+ public String call() throws Exception
+ {
+ throw new Exception("DON'T FREAK OUT");
+ }
+ }, "foo"));
+ Assert.assertFalse(futureCache.data.containsKey("foo"));
+ }
+}
Added: kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/StringLoader.java
===================================================================
--- kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/StringLoader.java (rev 0)
+++ kernel/trunk/exo.kernel.component.cache/src/test/java/org/exoplatform/services/cache/future/StringLoader.java 2011-07-04 17:12:39 UTC (rev 4588)
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2011 eXo Platform SAS.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.exoplatform.services.cache.future;
+
+import java.util.concurrent.Callable;
+
+/**
+ * @author <a href="mailto:julien.viet at exoplatform.com">Julien Viet</a>
+ * @version $Revision$
+ */
+public class StringLoader implements Loader<String, String, Callable<String>>
+{
+ public String retrieve(Callable<String> context, String key) throws Exception
+ {
+ return context.call();
+ }
+}
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