/**
* Open a copy of the map in read-only mode.
*
* @return the opened map
*/
protected MVMap<K, V> openReadOnly() {
MVMap<K, V> m = new MVMap<K, V>(keyType, valueType);
m.readOnly = true;
HashMap<String, String> config = New.hashMap();
config.put("id", String.valueOf(id));
config.put("createVersion", String.valueOf(createVersion));
m.init(store, config);
m.root = root;
return m;
}
/**
* Open an old version for the given map.
*
* @param version the version
* @return the map
*/
public MVMap<K, V> openVersion(long version) {
if (readOnly) {
throw DataUtils.newUnsupportedOperationException(
"This map is read-only - need to call the method on the writable map");
}
DataUtils.checkArgument(
version >= createVersion,
"Unknown version {0}; this map was created in version is {1}",
version,
createVersion);
Page newest = null;
// need to copy because it can change
Page r = root;
if (version >= r.getVersion()
&& (version == store.getCurrentVersion()
|| r.getVersion() >= 0
|| version <= createVersion
|| store.getFile() == null)) {
newest = r;
} else {
// find the newest page that has a getVersion() <= version
int i = searchRoot(version);
if (i < 0) {
// not found
if (i == -1) {
// smaller than all in-memory versions
return store.openMapVersion(version, id, this);
}
i = -i - 2;
}
newest = oldRoots.get(i);
}
MVMap<K, V> m = openReadOnly();
m.root = newest;
return m;
}