ObjectCache Class

Summary

Abstract class to provide cache support.

Syntax

C++/CLI

Java

Python

[DefaultMemberAttribute("Item")] 
public abstract class ObjectCache

public [DefaultMemberAttribute(L"Item")] 
   ref class ObjectCache abstract

public abstract class ObjectCache

class ObjectCache:

Remarks

Refer to Document Toolkit and Caching for more information on how the cache is used with the LEADTOOLS Document library and how to set up optional custom cache provider.

LEADTOOLS provides the FileCache object that implements ObjectCache.

Example

Java

using Leadtools.Caching; 
 
 
public void FileCacheConfigurationExample() 
{ 
   // XML file to save the cache configuration 
   string cacheConfigFile = Path.Combine(LEAD_VARS.ImagesDir, "filecache.xml"); 
 
   string cacheDir = Path.Combine(LEAD_VARS.ImagesDir, "cache"); 
   // This is optional and can be null if not needed 
   string cacheVirtualDir = "http://localhost/cache"; 
 
   // Create the LEADTOOLS FileCache object and set it up 
 
   var cache1 = new FileCache(); 
   cache1.CacheDirectory = cacheDir; 
   if (cacheVirtualDir != null) 
      cache1.CacheVirtualDirectory = new Uri(cacheVirtualDir); 
   cache1.PolicySerializationMode = CacheSerializationMode.Json; 
   cache1.DataSerializationMode = CacheSerializationMode.Json; 
   cache1.DefaultRegion = "defaultRegion"; 
   cache1.AccessTimeout = TimeSpan.FromSeconds(5); 
 
   Console.WriteLine("cache1 ready"); 
 
   // Set the policy, expires in 1 day 
 
   var defaultPolicy = new CacheItemPolicy(); 
   var absoluteExpiration = DateTime.Now; 
   absoluteExpiration = absoluteExpiration.AddDays(1); 
   defaultPolicy.AbsoluteExpiration = absoluteExpiration; 
   cache1.DefaultPolicy = defaultPolicy; 
 
   // Cache is ready, save its configuration to the file 
   using (var stream = File.Create(cacheConfigFile)) 
      cache1.SaveConfiguration(stream, true); 
 
   // Add an item 
   CacheItem<string> cacheItem = new CacheItem<string>("key1", "value1", "region1"); 
   Console.WriteLine("Adding {0}.{1} with value:{2} to cache1", cacheItem.RegionName, cacheItem.Key, cacheItem.Value); 
   cache1.Add(cacheItem, new CacheItemPolicy()); 
   // Check it 
   CacheItem<string> result = cache1.GetCacheItem<string>("key1", "region1"); 
   Assert.AreEqual(cacheItem.Value, result.Value); 
 
   // Now, call a separate function with just the configuration file to load and setup the cache and read the item back 
   InitFromConfigurationAndCheckCache(cacheConfigFile, cacheItem); 
} 
 
private static void InitFromConfigurationAndCheckCache(string cacheConfigFile, CacheItem<string> originalItem) 
{ 
   // Create the cache from the configuration file 
   // Note that we can use the base ObjectCache object here, we do not need to know the exact type 
   ObjectCache cache2 = null; 
 
   using (var stream = File.OpenRead(cacheConfigFile)) 
      cache2 = ObjectCache.CreateFromConfigurations(stream, null); 
 
   Console.WriteLine("cache2 loaded from {0}", cacheConfigFile); 
 
   // Read the item we previously saved and check its value 
   CacheItem<string> result = cache2.GetCacheItem<string>(originalItem.Key, originalItem.RegionName); 
   Console.WriteLine("Reading {0}.{1} with value:{2} to cache1", result.RegionName, result.Key, result.Value); 
   Assert.AreEqual(originalItem.Value, result.Value); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

 
import static org.junit.Assert.assertTrue; 
 
import java.io.File; 
import java.io.IOException; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.util.Calendar; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
 
import leadtools.*; 
import leadtools.caching.*; 
 
 
public void fileCacheConfigurationExample() throws MalformedURLException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
 
   // XML file to save the cache configuration 
   String cacheConfigFile = combine(LEAD_VARS_IMAGES_DIR, "filecache.xml"); 
   String cacheDir = combine(LEAD_VARS_IMAGES_DIR, "cache"); 
 
   // This is optional and can be null if not needed 
   String cacheVirtualDir = "http://localhost/cache"; 
 
   // Create the LEADTOOLS FileCache object and set it up 
   FileCache cache1 = new FileCache(); 
   cache1.setCacheDirectory(cacheDir); 
   if (cacheVirtualDir != null) 
      cache1.setCacheVirtualDirectory(new URL(cacheVirtualDir)); 
   cache1.setPolicySerializationMode(CacheSerializationMode.JSON); 
   cache1.setDataSerializationMode(CacheSerializationMode.JSON); 
   cache1.setDefaultRegion("defaultRegion"); 
   cache1.setAccessTimeout(5000); 
 
   System.out.println("cache1 set up and ready"); 
 
   // Set the policy, expires in 1 day 
   CacheItemPolicy defaultPolicy = new CacheItemPolicy(); 
   Calendar calendar = Calendar.getInstance(); 
   calendar.add(Calendar.DATE, 1); 
 
   defaultPolicy.setAbsoluteExpiration(calendar.getTime()); 
   cache1.setDefaultPolicy(defaultPolicy); 
 
   // Cache is ready, save its configuration to the file 
   ILeadStream stream = LeadStreamFactory.create(cacheConfigFile); 
 
   cache1.saveConfiguration(stream, true); 
 
   // Add an item 
   CacheItem<String> cacheItem = new CacheItem<String>("key1", "value1", "region1"); 
   System.out.printf("Adding %s.%s with value: %s to cache1%n", cacheItem.getRegionName(), cacheItem.getKey(), 
         cacheItem.getValue()); 
   cache1.add(cacheItem, String.class, new CacheItemPolicy()); 
 
   // Now, call a separate function with just the configuration file to load and 
   // setup the cache and read the item back 
   initFromConfigurationAndCheckCache(cacheConfigFile, cacheItem); 
   stream.dispose(); 
} 
 
private void initFromConfigurationAndCheckCache(String cacheConfigFile, CacheItem<String> originalItem) { 
   // Create the cache from the configuration file 
   // Note that we can use the base ObjectCache object here, we do not need to know 
   // the exact type 
   ObjectCache cache2 = null; 
   ILeadStream stream = LeadStreamFactory.create(cacheConfigFile); 
   cache2 = ObjectCache.createFromConfigurations(stream, null); 
   stream.dispose(); 
 
   System.out.println("cache2 loaded from " + cacheConfigFile); 
 
   // Read the item we previously saved and check its value 
   CacheItem<String> result = cache2.getCacheItem(originalItem.getKey(), String.class, originalItem.getRegionName()); 
   System.out.printf("Reading %s.%s with value: %s to cache1%n", result.getRegionName(), result.getKey(), 
         result.getValue()); 
   assertTrue("Saved and loaded values are not the same", originalItem.getValue().equals(result.getValue())); 
}

Requirements

Target Platforms

Reference

ObjectCache Members

Leadtools.Caching Namespace

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Help Version 23.0.2024.2.29

Leadtools.Caching Assembly

Introduction

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Namespaces

Leadtools.Caching Namespace

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