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Merge branch '1.3.x'
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wilkinsona committed Jun 1, 2016
2 parents 436b58a + f3e9f1e commit a3f4b3c
Showing 1 changed file with 161 additions and 113 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
Expand All @@ -44,22 +45,24 @@ public class FileSystemWatcher {

private static final long DEFAULT_QUIET_PERIOD = 400;

private List<FileChangeListener> listeners = new ArrayList<FileChangeListener>();
private final List<FileChangeListener> listeners = new ArrayList<FileChangeListener>();

private final boolean daemon;

private final long pollInterval;

private final long quietPeriod;

private Thread watchThread;
private final AtomicInteger remainingScans = new AtomicInteger(-1);

private AtomicInteger remainingScans = new AtomicInteger(-1);
private final Map<File, FolderSnapshot> folders = new HashMap<File, FolderSnapshot>();

private Map<File, FolderSnapshot> folders = new LinkedHashMap<File, FolderSnapshot>();
private Thread watchThread;

private FileFilter triggerFilter;

private final Object monitor = new Object();

/**
* Create a new {@link FileSystemWatcher} instance.
*/
Expand Down Expand Up @@ -89,10 +92,12 @@ public FileSystemWatcher(boolean daemon, long pollInterval, long quietPeriod) {
* {@link #start() started}.
* @param fileChangeListener the listener to add
*/
public synchronized void addListener(FileChangeListener fileChangeListener) {
public void addListener(FileChangeListener fileChangeListener) {
Assert.notNull(fileChangeListener, "FileChangeListener must not be null");
checkNotStarted();
this.listeners.add(fileChangeListener);
synchronized (this.monitor) {
checkNotStarted();
this.listeners.add(fileChangeListener);
}
}

/**
Expand All @@ -102,8 +107,10 @@ public synchronized void addListener(FileChangeListener fileChangeListener) {
*/
public void addSourceFolders(Iterable<File> folders) {
Assert.notNull(folders, "Folders must not be null");
for (File folder : folders) {
addSourceFolder(folder);
synchronized (this.monitor) {
for (File folder : folders) {
addSourceFolder(folder);
}
}
}

Expand All @@ -112,54 +119,49 @@ public void addSourceFolders(Iterable<File> folders) {
* {@link #start() started}.
* @param folder the folder to monitor
*/
public synchronized void addSourceFolder(File folder) {
public void addSourceFolder(File folder) {
Assert.notNull(folder, "Folder must not be null");
Assert.isTrue(folder.isDirectory(),
"Folder '" + folder + "' must exist and must" + " be a directory");
checkNotStarted();
this.folders.put(folder, null);
synchronized (this.monitor) {
checkNotStarted();
this.folders.put(folder, null);
}
}

/**
* Set an optional {@link FileFilter} used to limit the files that trigger a change.
* @param triggerFilter a trigger filter or null
*/
public synchronized void setTriggerFilter(FileFilter triggerFilter) {
this.triggerFilter = triggerFilter;
public void setTriggerFilter(FileFilter triggerFilter) {
synchronized (this.monitor) {
this.triggerFilter = triggerFilter;
}
}

private void checkNotStarted() {
Assert.state(this.watchThread == null, "FileSystemWatcher already started");
synchronized (this.monitor) {
Assert.state(this.watchThread == null, "FileSystemWatcher already started");
}
}

/**
* Start monitoring the source folder for changes.
*/
public synchronized void start() {
saveInitialSnapshots();
if (this.watchThread == null) {
this.watchThread = new Thread() {
@Override
public void run() {
int remaining = FileSystemWatcher.this.remainingScans.get();
while (remaining > 0 || remaining == -1) {
try {
if (remaining > 0) {
FileSystemWatcher.this.remainingScans.decrementAndGet();
}
scan();
}
catch (InterruptedException ex) {
// Ignore
}
remaining = FileSystemWatcher.this.remainingScans.get();
}
};
};
this.watchThread.setName("File Watcher");
this.watchThread.setDaemon(this.daemon);
this.remainingScans = new AtomicInteger(-1);
this.watchThread.start();
public void start() {
synchronized (this.monitor) {
saveInitialSnapshots();
if (this.watchThread == null) {
Map<File, FolderSnapshot> localFolders = new HashMap<File, FolderSnapshot>();
localFolders.putAll(this.folders);
this.watchThread = new Thread(new Watcher(this.remainingScans,
new ArrayList<FileChangeListener>(this.listeners),
this.triggerFilter, this.pollInterval, this.quietPeriod,
localFolders));
this.watchThread.setName("File Watcher");
this.watchThread.setDaemon(this.daemon);
this.watchThread.start();
}
}
}

Expand All @@ -169,96 +171,142 @@ private void saveInitialSnapshots() {
}
}

private void scan() throws InterruptedException {
Thread.sleep(this.pollInterval - this.quietPeriod);
Map<File, FolderSnapshot> previous;
Map<File, FolderSnapshot> current = this.folders;
do {
previous = current;
current = getCurrentSnapshots();
Thread.sleep(this.quietPeriod);
}
while (isDifferent(previous, current));
if (isDifferent(this.folders, current)) {
updateSnapshots(current.values());
}
}

private boolean isDifferent(Map<File, FolderSnapshot> previous,
Map<File, FolderSnapshot> current) {
if (!previous.keySet().equals(current.keySet())) {
return true;
}
for (Map.Entry<File, FolderSnapshot> entry : previous.entrySet()) {
FolderSnapshot previousFolder = entry.getValue();
FolderSnapshot currentFolder = current.get(entry.getKey());
if (!previousFolder.equals(currentFolder, this.triggerFilter)) {
return true;
}
}
return false;
}

private Map<File, FolderSnapshot> getCurrentSnapshots() {
Map<File, FolderSnapshot> snapshots = new LinkedHashMap<File, FolderSnapshot>();
for (File folder : this.folders.keySet()) {
snapshots.put(folder, new FolderSnapshot(folder));
}
return snapshots;
}

private void updateSnapshots(Collection<FolderSnapshot> snapshots) {
Map<File, FolderSnapshot> updated = new LinkedHashMap<File, FolderSnapshot>();
Set<ChangedFiles> changeSet = new LinkedHashSet<ChangedFiles>();
for (FolderSnapshot snapshot : snapshots) {
FolderSnapshot previous = this.folders.get(snapshot.getFolder());
updated.put(snapshot.getFolder(), snapshot);
ChangedFiles changedFiles = previous.getChangedFiles(snapshot,
this.triggerFilter);
if (!changedFiles.getFiles().isEmpty()) {
changeSet.add(changedFiles);
}
}
if (!changeSet.isEmpty()) {
fireListeners(Collections.unmodifiableSet(changeSet));
}
this.folders = updated;
}

private void fireListeners(Set<ChangedFiles> changeSet) {
for (FileChangeListener listener : this.listeners) {
listener.onChange(changeSet);
}
}

/**
* Stop monitoring the source folders.
*/
public synchronized void stop() {
public void stop() {
stopAfter(0);
}

/**
* Stop monitoring the source folders.
* @param remainingScans the number of remaining scans
*/
synchronized void stopAfter(int remainingScans) {
Thread thread = this.watchThread;
if (thread != null) {
this.remainingScans.set(remainingScans);
if (remainingScans <= 0) {
thread.interrupt();
void stopAfter(int remainingScans) {
synchronized (this.monitor) {
Thread thread = this.watchThread;
if (thread != null) {
this.remainingScans.set(remainingScans);
if (remainingScans <= 0) {
thread.interrupt();
}
if (Thread.currentThread() != thread) {
try {
thread.join();
}
catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
this.watchThread = null;
}
if (Thread.currentThread() != thread) {
}
}

private static final class Watcher implements Runnable {

private final AtomicInteger remainingScans;

private final List<FileChangeListener> listeners;

private final FileFilter triggerFilter;

private final long pollInterval;

private final long quietPeriod;

private Map<File, FolderSnapshot> folders;

private Watcher(AtomicInteger remainingScans, List<FileChangeListener> listeners,
FileFilter triggerFilter, long pollInterval, long quietPeriod,
Map<File, FolderSnapshot> folders) {
this.remainingScans = remainingScans;
this.listeners = listeners;
this.triggerFilter = triggerFilter;
this.pollInterval = pollInterval;
this.quietPeriod = quietPeriod;
this.folders = folders;
}

@Override
public void run() {
int remainingScans = this.remainingScans.get();
while (remainingScans > 0 || remainingScans == -1) {
try {
thread.join();
if (remainingScans > 0) {
this.remainingScans.decrementAndGet();
}
scan();
}
catch (InterruptedException ex) {
Thread.currentThread().interrupt();
// Ignore
}
remainingScans = this.remainingScans.get();
}
};

private void scan() throws InterruptedException {
Thread.sleep(this.pollInterval - this.quietPeriod);
Map<File, FolderSnapshot> previous;
Map<File, FolderSnapshot> current = this.folders;
do {
previous = current;
current = getCurrentSnapshots();
Thread.sleep(this.quietPeriod);
}
while (isDifferent(previous, current));
if (isDifferent(this.folders, current)) {
updateSnapshots(current.values());
}
this.watchThread = null;
}

private boolean isDifferent(Map<File, FolderSnapshot> previous,
Map<File, FolderSnapshot> current) {
if (!previous.keySet().equals(current.keySet())) {
return true;
}
for (Map.Entry<File, FolderSnapshot> entry : previous.entrySet()) {
FolderSnapshot previousFolder = entry.getValue();
FolderSnapshot currentFolder = current.get(entry.getKey());
if (!previousFolder.equals(currentFolder, this.triggerFilter)) {
return true;
}
}
return false;
}

private Map<File, FolderSnapshot> getCurrentSnapshots() {
Map<File, FolderSnapshot> snapshots = new LinkedHashMap<File, FolderSnapshot>();
for (File folder : this.folders.keySet()) {
snapshots.put(folder, new FolderSnapshot(folder));
}
return snapshots;
}

private void updateSnapshots(Collection<FolderSnapshot> snapshots) {
Map<File, FolderSnapshot> updated = new LinkedHashMap<File, FolderSnapshot>();
Set<ChangedFiles> changeSet = new LinkedHashSet<ChangedFiles>();
for (FolderSnapshot snapshot : snapshots) {
FolderSnapshot previous = this.folders.get(snapshot.getFolder());
updated.put(snapshot.getFolder(), snapshot);
ChangedFiles changedFiles = previous.getChangedFiles(snapshot,
this.triggerFilter);
if (!changedFiles.getFiles().isEmpty()) {
changeSet.add(changedFiles);
}
}
if (!changeSet.isEmpty()) {
fireListeners(Collections.unmodifiableSet(changeSet));
}
this.folders = updated;
}

private void fireListeners(Set<ChangedFiles> changeSet) {
for (FileChangeListener listener : this.listeners) {
listener.onChange(changeSet);
}
}

}

}

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