Example: Caching a command object

Cacheable commands are stored in the cache for reuse with a similar mechanism for servlets and JSPs.

This example of command caching is a simple stock quote command.

 

Example

The following is a stock quote command bean. It accepts a ticker as an input parameter and produces a price as its output parameter.

public class QuoteCommand extends CacheableCommandImpl
{
    private String ticker;
    private double price;
    
// called to validate that command input parameters have been set
    public boolean isReadyToCallExecute() {
      return (ticker!=null);
    }
    
// called by a cache-hit to copy output properties to this object
    public void setOutputProperties(TargetableCommand fromCommand) {
        QuoteCommand f = (QuoteCommand)fromCommand;
        this.price = f.price;
    }

   
// business logic method called when the stock price must be retrieved
    public void performExecute()throws Exception {...}

    
//input parameters for the command
    public void setTicker(String ticker) { this.ticker=ticker;}
    public String getTicker() { return ticker;}

    
//output parameters for the command
    public double getPrice()  { return price;};
}

 

Example

To cache the above command object using the stock ticker as the cache key and using a 60 second time-to-live, use the following cache policy:

<cache>
  <cache-entry>
    <class>command</class>
    <sharing-policy>not-shared</sharing-policy>
    <name>QuoteCommand</name>
    <cache-id>
      <component type="method" id="getTicker">
        <required>true</required>
      </component>
      <priority>3</priority>
      <timeout>60</timeout>
    </cache-id>
  </cache-entry>
</cache>

---

 

Related tasks

Set command caching