getNumProxyServers

 import com.screenscraper.util.*;

 // Create a new ProxyServerPool object.
 proxyServerPool = new ProxyServerPool();

 // Must be set on the session before other calls are made
 session.setProxyServerPool(proxyServerPool);

 // This tells the pool to populate itself from a file
 proxyServerPool.populateFromFile( "proxies.txt" );

 // Validate proxies up to 25 proxies at a time.
 proxyServerPool.setNumProxiesToValidateConcurrently( 25 );

 // Set timout interval
 proxyServerPool.filter( 7 );
 
 // Check number of available proxies
 if (proxyServerPool.getNumProxyServers() < 4) {
 {
    // Repopulate available proxies
    proxyServerPool.setRepopulateThreshold( 5 );
 }