more efficient persisting

core/src/main/groovy/com/muwire/core/files/PersisterService.groovy

@@ -103,10 +103,12 @@ class PersisterService extends Service {
 	private void persistFiles() {
 		location.delete()
 		def sharedFiles = fileSource.getSharedFiles()
+		location.withPrintWriter { writer ->
 			sharedFiles.each { k, v ->
 				def json = toJson(k,v)
 				json = JsonOutput.toJson(json)
-			location.append "$json\n"
+				writer.println json
+			}
 		}
 	}
 	

core/src/main/groovy/com/muwire/core/hostcache/HostCache.groovy

@@ -107,13 +107,15 @@ class HostCache extends Service {
 	
 	private void save() {
 		storage.delete()
+		storage.withPrintWriter { writer ->
 			hosts.each { dest, host ->
 				if (allowHost(host)) {
 					def map = [:]
 					map.destination = dest.toBase64()
 					map.failures = host.failures
 					def json = JsonOutput.toJson(map)
-				storage.append("${json}\n")
+					writer.println json
+				}
 			}
 		}
 	}

core/src/main/groovy/com/muwire/core/trust/TrustService.groovy

@@ -49,12 +49,16 @@ class TrustService extends Service {
 	
 	private void persist() {
 		persistGood.delete()
+		persistGood.withPrintWriter { writer ->
 			good.each {
-			persistGood.append("${it.toBase64()}\n")
+				writer.println it.toBase64()
+			}
 		}
 		persistBad.delete()
+		persistBad.withPrintWriter { writer ->
 			bad.each { 
-			persistBad.append("${it.toBase64()}\n")
+				writer.println it.toBase64()
+			}
 		}
 	}