ALF-9613: caching content store

http://issues.alfresco.com/jira/browse/ALF-9613


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@29662 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/content/caching/ContentCacheImpl.java

@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2005-2011 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco 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 Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.repo.content.caching;
+
+import java.io.File;
+
+import net.sf.ehcache.CacheManager;
+
+import org.alfresco.repo.cache.EhCacheAdapter;
+import org.alfresco.repo.content.filestore.FileContentReader;
+import org.alfresco.repo.content.filestore.FileContentWriter;
+import org.alfresco.service.cmr.repository.ContentIOException;
+import org.alfresco.service.cmr.repository.ContentReader;
+import org.alfresco.service.cmr.repository.ContentStreamListener;
+import org.alfresco.service.cmr.repository.ContentWriter;
+import org.alfresco.util.TempFileProvider;
+
+/**
+ * The one and only implementation of the ContentCache class.
+ * <p>
+ * Binary content data itself is stored on disk in temporary files managed
+ * by Alfresco (see {@link org.alfresco.util.TempFileProvider}).
+ * <p>
+ * The in-memory lookup table is provided by Ehcache.
+ * 
+ * @author Matt Ward
+ */
+public class ContentCacheImpl implements ContentCache
+{
+    private static final String CACHE_DIR = "caching_cs";
+    private static final String TMP_FILE_EXTENSION = ".tmp";
+    private static final String EHCACHE_NAME = "contentStoreCache";
+    private static final long T24_HOURS = 86400;
+    private final File cacheRoot = TempFileProvider.getLongLifeTempDir(CACHE_DIR);
+    private EhCacheAdapter<String, String> memoryStore;
+    
+    public ContentCacheImpl()
+    {
+        // TODO: Configuration to be moved out into Spring
+        memoryStore = new EhCacheAdapter<String, String>();
+        configureMemoryStore();   
+    }
+
+    private void configureMemoryStore()
+    {
+        CacheManager manager = CacheManager.getInstance();
+        
+        // Create the cache if it hasn't already been created.
+        if (!manager.cacheExists(EHCACHE_NAME))
+        {
+            net.sf.ehcache.Cache memoryOnlyCache = 
+                new net.sf.ehcache.Cache(EHCACHE_NAME, 10000, false, false, T24_HOURS, T24_HOURS);
+            
+            manager.addCache(memoryOnlyCache);
+        }
+        
+        memoryStore.setCache(manager.getCache(EHCACHE_NAME));
+    }
+    
+    
+    @Override
+    public boolean contains(String contentUrl)
+    {
+        return memoryStore.contains(contentUrl);
+    }
+
+    
+    
+    @Override
+    public ContentReader getReader(String contentUrl)
+    {
+        if (memoryStore.contains(contentUrl))
+        {
+            String path = memoryStore.get(contentUrl);
+            return new FileContentReader(new File(path), contentUrl);
+        }
+        
+        throw new CacheMissException(contentUrl);
+    }
+
+    
+    
+    @Override
+    public boolean put(String contentUrl, ContentReader source)
+    {
+        File cacheFile = createCacheFile(contentUrl);
+        
+        // Copy the content from the source into a cache file
+        if (source.getSize() > 0L)
+        {
+            source.getContent(cacheFile);
+            // Add a record of the cached file to the in-memory cache.
+            memoryStore.put(contentUrl, cacheFile.getAbsolutePath());
+            return true;
+        }
+
+        return false;
+    }
+
+    
+    /**
+     * Create a File object and makes any intermediate directories in the path.
+     * 
+     * @param contentUrl
+     * @return File
+     */
+    private File createCacheFile(String contentUrl)
+    {
+        File path = new File(cacheRoot, pathFromUrl(contentUrl));
+        File parentDir = path.getParentFile();
+        
+        parentDir.mkdirs();
+        
+        File cacheFile = TempFileProvider.createTempFile(path.getName(), TMP_FILE_EXTENSION, parentDir);
+        return cacheFile;
+    }
+    
+    
+    
+    
+    /*
+     * @see org.alfresco.repo.content.caching.ContentCache#remove(java.lang.String)
+     */
+    @Override
+    public void remove(String contentUrl)
+    {
+        // Remove from the in-memory cache, but not from disk. Let the clean-up process do this asynchronously.
+        memoryStore.remove(contentUrl);
+    }
+
+    
+    /*
+     * @see org.alfresco.repo.content.caching.ContentCache#getWriter(org.alfresco.repo.content.ContentContext)
+     */
+    @Override
+    public ContentWriter getWriter(final String url)
+    {
+        // Get a writer to a cache file.
+        final File cacheFile = createCacheFile(url);
+        ContentWriter writer = new FileContentWriter(cacheFile);
+        
+        // Attach a listener to populate the in-memory store when done writing.
+        writer.addListener(new ContentStreamListener()
+        {
+            @Override
+            public void contentStreamClosed() throws ContentIOException
+            {
+                memoryStore.put(url, cacheFile.getAbsolutePath());
+            }
+        });
+        
+        return writer;
+    }
+
+    
+    /**
+     * Converts a content URL to a relative path name where the protocol will
+     * be the name of a subdirectory. For example:
+     * <p>
+     * store://2011/8/5/15/4/386595e0-3b52-4d5c-a32d-df9d0b9fd56e.bin
+     * <p>
+     * will become:
+     * <p>
+     * store/2011/8/5/15/4/386595e0-3b52-4d5c-a32d-df9d0b9fd56e.bin
+     * 
+     * @param contentUrl
+     * @return String representation of relative path to file.
+     */
+    private String pathFromUrl(String contentUrl)
+    {
+        return contentUrl.replaceFirst("://", "/");
+    }
+}