added basic server side image caching

etc/ehcache-1.5.0.xsd

@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
+    <xs:element name="ehcache" >
+        <xs:complexType>
+            <xs:sequence>
+                <xs:element minOccurs="0" maxOccurs="1" ref="diskStore"/>
+                <xs:element minOccurs="0" maxOccurs="1"
+                            ref="cacheManagerEventListenerFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1"
+                            ref="cacheManagerPeerProviderFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1"
+                            ref="cacheManagerPeerListenerFactory"/>
+                <xs:element ref="defaultCache"/>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cache"/>
+            </xs:sequence>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="diskStore">
+        <xs:complexType>
+            <xs:attribute name="path" use="optional" />
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheManagerEventListenerFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheManagerPeerProviderFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheManagerPeerListenerFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <!-- add clone support for addition of cacheExceptionHandler. Important! -->
+    <xs:element name="defaultCache">
+        <xs:complexType>
+            <xs:sequence>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheEventListenerFactory"/>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheExtensionFactory"/>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheLoaderFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1" ref="bootstrapCacheLoaderFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1" ref="cacheExceptionHandlerFactory"/>
+            </xs:sequence>
+            <xs:attribute name="diskExpiryThreadIntervalSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="diskSpoolBufferSizeMB" use="optional" type="xs:integer"/>
+            <xs:attribute name="diskPersistent" use="optional" type="xs:boolean"/>
+            <xs:attribute name="eternal" use="required" type="xs:boolean"/>
+            <xs:attribute name="maxElementsInMemory" use="required" type="xs:integer"/>
+            <xs:attribute name="memoryStoreEvictionPolicy" use="optional" type="xs:string"/>
+            <xs:attribute name="overflowToDisk" use="required" type="xs:boolean"/>
+            <xs:attribute name="timeToIdleSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="timeToLiveSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="maxElementsOnDisk" use="optional" type="xs:integer"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cache">
+        <xs:complexType>
+            <xs:sequence>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheEventListenerFactory"/>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheExtensionFactory"/>
+                <xs:element minOccurs="0" maxOccurs="unbounded" ref="cacheLoaderFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1" ref="bootstrapCacheLoaderFactory"/>
+                <xs:element minOccurs="0" maxOccurs="1" ref="cacheExceptionHandlerFactory"/>
+            </xs:sequence>
+            <xs:attribute name="diskExpiryThreadIntervalSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="diskSpoolBufferSizeMB" use="optional" type="xs:integer"/>
+            <xs:attribute name="diskPersistent" use="optional" type="xs:boolean"/>
+            <xs:attribute name="eternal" use="required" type="xs:boolean"/>
+            <xs:attribute name="maxElementsInMemory" use="required" type="xs:integer"/>
+            <xs:attribute name="memoryStoreEvictionPolicy" use="optional" type="xs:string"/>
+            <xs:attribute name="name" use="required" type="xs:string"/>
+            <xs:attribute name="overflowToDisk" use="required" type="xs:boolean"/>
+            <xs:attribute name="timeToIdleSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="timeToLiveSeconds" use="optional" type="xs:integer"/>
+            <xs:attribute name="maxElementsOnDisk" use="optional" type="xs:integer"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheEventListenerFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="bootstrapCacheLoaderFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheExtensionFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheExceptionHandlerFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+    <xs:element name="cacheLoaderFactory">
+        <xs:complexType>
+            <xs:attribute name="class" use="required"/>
+            <xs:attribute name="properties" use="optional"/>
+            <xs:attribute name="propertySeparator" use="optional"/>
+        </xs:complexType>
+    </xs:element>
+</xs:schema>

etc/ehcache.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="ehcache-1.5.0.xsd">
+
+  <diskStore path="java.io.tmpdir"/>
+
+  <defaultCache eternal="false" maxElementsInMemory="200" overflowToDisk="false" />
+
+  <cache
+    name="imageCache"
+    maxElementsInMemory="120"
+    maxElementsOnDisk="5000"
+    eternal="true"
+    overflowToDisk="true"
+    diskPersistent="true"
+    diskSpoolBufferSizeMB="20"
+    diskExpiryThreadIntervalSeconds="1"
+    memoryStoreEvictionPolicy="LFU"/>
+
+</ehcache>

pom.xml

@@ -108,6 +108,11 @@
       <version>2.4</version>
       <scope>provided</scope>
     </dependency>
+    <dependency>
+      <groupId>net.sf.ehcache</groupId>
+      <artifactId>ehcache</artifactId>
+      <version>1.5.0</version>
+    </dependency>
   </dependencies>
   <repositories>
     <repository>

src/org/forkalsrud/album/web/AlbumServlet.java

@@ -4,6 +4,7 @@ import java.awt.Graphics2D;
 import java.awt.RenderingHints;
 import java.awt.geom.AffineTransform;
 import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.util.Iterator;
@@ -20,6 +21,10 @@ import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import net.sf.ehcache.Cache;
+import net.sf.ehcache.CacheManager;
+import net.sf.ehcache.Element;
+
 import org.forkalsrud.album.exif.Dimension;
 import org.forkalsrud.album.exif.DirectoryEntry;
 import org.forkalsrud.album.exif.Entry;
@@ -31,6 +36,7 @@ public class AlbumServlet
 {
 	File base;
 	String basePrefix;
+	Cache imageCache;
 
     @Override
     public void init()
@@ -39,6 +45,9 @@ public class AlbumServlet
         System.out.println("in init of Album");
         base = new File(getServletConfig().getInitParameter("base")).getAbsoluteFile();
         basePrefix = "/" + base.getName();
+
+        CacheManager cacheManager = new CacheManager();
+        imageCache = cacheManager.getCache("imageCache");
     }
 
     @Override
@@ -75,12 +84,13 @@ public class AlbumServlet
             return;
         }
 
-        if (req.getParameter("size") != null) {
+        String size = req.getParameter("size");
+        if (size != null) {
 
             try {
                 res.setContentType("image/jpeg");
                 FileEntry e = (FileEntry)DirectoryEntry.getEntry(file);
-                scaleImage(req, res, file, e.getThumbnail(), req.getParameter("size"));
+                scaleImage(req, res, file, e.getThumbnail(), size);
                 res.setStatus(HttpServletResponse.SC_OK);
                 return;
             } catch (Exception e) {
@@ -134,7 +144,7 @@ public class AlbumServlet
         return reqDate > 0 && fDate > 0 && fDate <= reqDate;
     }
 
-    synchronized void scaleImage(HttpServletRequest req, HttpServletResponse res, File file, Thumbnail thumbnail, String size) throws IOException {
+    void scaleImage(HttpServletRequest req, HttpServletResponse res, File file, Thumbnail thumbnail, String size) throws IOException {
 
         if (notModified(req, file)) {
             res.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
@@ -150,6 +160,24 @@ public class AlbumServlet
         res.setDateHeader("Last-Modified", file.lastModified());
         res.setHeader("ETag", fileEtag);
 
+
+        String key = file.getPath() + ":" + size;
+        Element element = imageCache.get(key);
+        if (element != null) {
+            CachedImage cimg = (CachedImage) element.getObjectValue();
+            if (cimg.lastModified == file.lastModified()) {
+                System.out.println("cache hit on " + key);
+                //res.setContentType(cimg.mimeType);
+                res.setContentLength(cimg.bits.length);
+                res.getOutputStream().write(cimg.bits);
+                return;
+            } else {
+                System.out.println("             " + key + " has changed so cache entry wil be refreshed");
+                imageCache.remove(key);
+            }
+        }
+
+      synchronized (this) {
         Dimension orig = thumbnail.getSize();
         Dimension outd;
         if (size.endsWith("h")) {
@@ -219,15 +247,26 @@ public class AlbumServlet
 
         Iterator<ImageWriter> writers = ImageIO.getImageWritersByFormatName("jpg");
         ImageWriter writer = writers.next();
-//        ImageWriteParam wParam = writer.getDefaultWriteParam();
+
-//        wParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
+        ByteArrayOutputStream bits = new ByteArrayOutputStream();
-//        wParam.setCompressionQuality(1.0f);
+
-        ImageOutputStream ios = ImageIO.createImageOutputStream(res.getOutputStream());
+        ImageOutputStream ios = ImageIO.createImageOutputStream(bits);
         writer.setOutput(ios);
-//        writer.write(null, new IIOImage(buf2, null, null), wParam);
         writer.write(buf2);
         ios.flush();
-        res.getOutputStream().close();
+
+        CachedImage cimg = new CachedImage();
+        cimg.lastModified = file.lastModified();
+        cimg.mimeType = "image/jpeg";
+        cimg.bits = bits.toByteArray();
+        imageCache.put(new Element(key, cimg));
+
+        System.out.println("             " + key + " added to the cache with size " + cimg.bits.length + " -- now " + imageCache.getSize() + " entries");
+
+        //res.setContentType(cimg.mimeType);
+        res.setContentLength(cimg.bits.length);
+        res.getOutputStream().write(cimg.bits);
+      }
     }
 
 
@@ -273,6 +312,12 @@ public class AlbumServlet
     		}
     	}
     }
+
+    static class CachedImage {
+        long lastModified;
+        String mimeType;
+        byte[] bits;
+    }
 }
 
 // eof