org.snmp4j.agent.io.DefaultMOPersistenceProvider Maven / Gradle / Ivy
/*_############################################################################
_##
_## SNMP4J-Agent - DefaultMOPersistenceProvider.java
_##
_## Copyright (C) 2005-2009 Frank Fock (SNMP4J.org)
_##
_## Licensed under the Apache License, Version 2.0 (the "License");
_## you may not use this file except in compliance with the License.
_## You may obtain a copy of the License at
_##
_## http://www.apache.org/licenses/LICENSE-2.0
_##
_## Unless required by applicable law or agreed to in writing, software
_## distributed under the License is distributed on an "AS IS" BASIS,
_## WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
_## See the License for the specific language governing permissions and
_## limitations under the License.
_##
_##########################################################################*/
package org.snmp4j.agent.io;
import java.io.*;
import java.net.URI;
import org.snmp4j.agent.MOServer;
/**
* The DefaultMOPersistenceProvider provides agent state
* persistence using a file with {@link DefaultMOInput} and
* {@link DefaultMOOutput} input/output.
*
* @author Frank Fock
* @version 1.2
*/
public class DefaultMOPersistenceProvider implements MOPersistenceProvider {
private MOServer[] server;
private String defaultURI;
/**
* Creates a persistence provider for the supplied {@link MOServer} instances.
* The content and state of the managed objects of those servers are subject
* to {@link #store} and {@link #restore} operations.
*
* @param server
* an array of MOServer instances (possibly empty).
* @param defaultURI
* the (optional) default URI (i.e., file path) to be used for this
* persistence provider.
*/
public DefaultMOPersistenceProvider(MOServer[] server, String defaultURI) {
this.server = server;
this.defaultURI = defaultURI;
}
/**
* Returns an unique ID of the persistence provider which should identify the
* format and type of the persistence provider.
*
* @return "default".
*/
public String getPersistenceProviderID() {
return "default";
}
/**
* Checks whether the supplied URI string is valid for this persistence
* provider.
*
* @param uri a string identifying a persistent storage location for this
* storage provider.
* @return true if the uri is valid,
* false otherwise.
*/
public boolean isValidPersistenceURI(String uri) {
try {
File f = getFile(uri);
return (f.isFile() && (f.canRead() || f.canWrite())) || !f.exists();
}
catch (Exception ex) {
return false;
}
}
private File getFile(String uri) {
File f;
if (uri.toUpperCase().startsWith("FILE:")) {
URI u = URI.create(uri);
f = new File(u);
}
else {
f = new File(uri);
}
return f;
}
/**
* Restore (load) agent state from the specified file URI or file name.
*
* @param uri a string pointing to the persistent storage file from which the
* agent state should be restored from. The format of he string is
* either a simple file name or an URI starting with "file:".
* @param importMode specifies how the agent's current state should be
* update while restoring a previous state.
* @throws IOException if the restore operation fails.
*/
public void restore(String uri, int importMode) throws IOException {
if (uri == null) {
uri = getDefaultURI();
}
ObjectInputStream ois = null;
try {
ois = new ObjectInputStream(new FileInputStream(getFile(uri)));
DefaultMOInput is = new DefaultMOInput(ois);
is.setOverwriteMode(importMode);
MOServerPersistence p = new MOServerPersistence(server);
p.loadData(is);
ois.close();
}
catch (IOException iox) {
throw iox;
}
finally {
if (ois != null) {
try { ois.close(); } catch (IOException iox) { }
}
}
}
/**
* Stores the current agent state to persistent storage specified by the
* supplied URI.
*
* @param uri a string pointing to the persistent storage file to use.
* The format of he string is either a simple file name or an URI
* starting with "file:".
* @throws IOException if the store operation fails.
*/
public void store(String uri) throws IOException {
if (uri == null) {
uri = getDefaultURI();
}
ObjectOutputStream oos = null;
try {
oos = new ObjectOutputStream(new FileOutputStream(getFile(uri)));
DefaultMOOutput os = new DefaultMOOutput(oos);
MOServerPersistence p = new MOServerPersistence(server);
p.saveData(os);
oos.flush();
oos.close();
}
catch (IOException iox) {
throw iox;
}
finally {
if (oos != null) {
try { oos.close(); } catch (IOException iox) { }
}
}
}
public String getDefaultURI() {
return defaultURI;
}
}