org.apache.jackrabbit.vault.fs.io.AutoSave Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.jackrabbit.vault.fs.io;
import java.util.HashSet;
import java.util.Set;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import org.apache.jackrabbit.vault.fs.spi.ProgressTracker;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* {@code AutoSave}...
*/
public class AutoSave {
/**
* default logger
*/
private static final Logger log = LoggerFactory.getLogger(AutoSave.class);
/**
* number of modified nodes
*/
private int numModified;
/**
* number of modified nodes at last save
*/
private int lastSave;
/**
* number of modified nodes that trigger a save. default is 1024
*/
private int threshold = 1024;
/**
* set that records the missing mandatory items. save has to be delay until they are resolved
*/
private final Set missingMandatory = new HashSet();
/**
* tracker to use to report progress messages
*/
private ProgressTracker tracker;
/**
* flag controlling if autosave should until simulate
*/
private boolean dryRun;
/**
* debug setting that allows to simulate autosave failures.
*/
private int debugFailEach;
/**
* debug counter used to trigger failures
*/
private int debugSaveCount;
public AutoSave() {
}
public AutoSave(int threshold) {
this.threshold = threshold;
}
public AutoSave copy() {
AutoSave ret = new AutoSave();
ret.threshold = threshold;
ret.numModified = numModified;
ret.lastSave = lastSave;
ret.tracker = tracker;
ret.dryRun = dryRun;
ret.missingMandatory.addAll(missingMandatory);
ret.debugFailEach = debugFailEach;
// don't copy save count, otherwise it will fail for ever.
// ret.debugSaveCount = debugSaveCount;
return ret;
}
public void setTracker(@Nullable ProgressTracker tracker) {
this.tracker = tracker;
}
public boolean isDryRun() {
return dryRun;
}
public void setDryRun(boolean dryRun) {
this.dryRun = dryRun;
}
/**
* Debug settings to allows to produce failures after each {@code debugFailEach} save.
* @param debugFailEach cardinal indicating when to fail
*/
public void setDebugFailEach(int debugFailEach) {
this.debugFailEach = debugFailEach;
}
/**
* Returns {@code true} if more than {@link #getThreshold()} nodes are
* modified.
* @return {@code true} if threshold reached.
*/
public boolean needsSave() {
boolean res = (numModified - lastSave) >= threshold;
if (res && !missingMandatory.isEmpty()) {
log.debug("Threshold of {} reached but still unresolved mandatory items.", threshold);
res = false;
}
return res;
}
/**
* saves the changes under the given node and resets the counter
* @param session the session to save. can be {@code null}
* @throws RepositoryException if an error occurs.
*/
public void save(@Nullable Session session) throws RepositoryException {
if (threshold == Integer.MAX_VALUE) {
log.trace("Save disabled.");
return;
}
int diff = numModified - lastSave;
log.debug("Threshold of {} reached. {} approx {} transient changes. {} unresolved", new Object[]{
threshold,
dryRun ? "dry run, reverting" : "saving",
diff,
missingMandatory.size()
});
if (tracker != null) {
if (dryRun) {
tracker.track("reverting approx " + diff + " nodes... (dry run)", "");
} else {
tracker.track("saving approx " + diff + " nodes...", "");
}
}
if (session != null) {
if (debugFailEach > 0 && debugSaveCount > 0 && debugSaveCount%debugFailEach == 0) {
String msg = String.format("Debugging provoked failure after %s saves.", debugSaveCount);
log.error(msg);
throw new RepositoryException(msg);
}
if (dryRun) {
session.refresh(false);
} else {
try {
session.save();
debugSaveCount++;
} catch (RepositoryException e) {
log.error("error during auto save - retrying after refresh...");
session.refresh(true);
session.save();
debugSaveCount++;
}
}
}
lastSave = numModified;
}
/**
* Returns the threshold
* @return the threshold
*/
public int getThreshold() {
return threshold;
}
/**
* Sets the threshold
* @param threshold the threshold
*/
public void setThreshold(int threshold) {
this.threshold = threshold;
}
/**
* Adds {@code num} modified
* @param num number of modified
* @return {@code true} if threshold is reached
*/
public boolean modified(int num) {
numModified+= num;
return needsSave();
}
public void markMissing(@Nonnull String path) {
missingMandatory.add(path);
}
public void markResolved(@Nonnull String path) {
missingMandatory.remove(path);
}
@Override
public String toString() {
return String.valueOf(threshold);
}
}