org.apache.sling.discovery.commons.providers.spi.base.ClusterSyncHistory Maven / Gradle / Ivy
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* 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
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package org.apache.sling.discovery.commons.providers.spi.base;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import org.apache.sling.discovery.commons.providers.BaseTopologyView;
public class ClusterSyncHistory {
class HistoryEntry {
BaseTopologyView view;
String msg;
String fullLine;
}
/** the date format used in the truncated log of topology events **/
private final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
protected List history = new LinkedList();
public List getSyncHistory() {
List snapshot;
synchronized(history) {
snapshot = Collections.unmodifiableList(history);
}
List result = new ArrayList(snapshot.size());
for (HistoryEntry historyEntry : snapshot) {
result.add(historyEntry.fullLine);
}
return result;
}
protected void addHistoryEntry(BaseTopologyView view, String msg) {
synchronized(history) {
for(int i = history.size() - 1; i>=0; i--) {
HistoryEntry entry = history.get(i);
if (!entry.view.equals(view)) {
// don't filter if the view starts differing,
// only filter for the last few entries where
// the view is equal
break;
}
if (entry.msg.equals(msg)) {
// if the view is equal and the msg matches
// then this is a duplicate entry, so ignore
return;
}
}
String fullLine = sdf.format(Calendar.getInstance().getTime()) + ": " + msg;
HistoryEntry newEntry = new HistoryEntry();
newEntry.view = view;
newEntry.fullLine = fullLine;
newEntry.msg = msg;
history.add(newEntry);
while (history.size() > 12) {
history.remove(0);
}
}
}
}