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Copyright 2010, Google Inc.
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*/
package com.google.refine;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.tools.tar.TarOutputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.refine.history.HistoryEntryManager;
import com.google.refine.model.Project;
import com.google.refine.preference.PreferenceStore;
import com.google.refine.preference.TopList;
/**
* ProjectManager is responsible for loading and saving the workspace and projects.
*
*
*/
public abstract class ProjectManager {
// last n expressions used across all projects
static protected final int s_expressionHistoryMax = 100;
// If a project has been idle this long, flush it from memory
static protected final int PROJECT_FLUSH_DELAY = 1000 * 60 * 15; // 15 minutes
// Don't spend more than this much time saving projects if doing a quick save
static protected final int QUICK_SAVE_MAX_TIME = 1000 * 30; // 30 secs
protected Map<Long, ProjectMetadata> _projectsMetadata;
protected PreferenceStore _preferenceStore;
final static Logger logger = LoggerFactory.getLogger("ProjectManager");
/**
* What caches the joins between projects.
*/
transient protected InterProjectModel _interProjectModel = new InterProjectModel();
/**
* Flag for heavy operations like creating or importing projects. Workspace saves are skipped while it's set.
*/
transient protected int _busy = 0;
/**
* While each project's metadata is loaded completely at start-up, each project's raw data
* is loaded only when the project is accessed by the user. This is because project
* metadata is tiny compared to raw project data. This hash map from project ID to project
* is more like a last accessed-last out cache.
*/
transient protected Map<Long, Project> _projects;
static public ProjectManager singleton;
protected ProjectManager(){
_projectsMetadata = new HashMap<Long, ProjectMetadata>();
_preferenceStore = new PreferenceStore();
_projects = new HashMap<Long, Project>();
preparePreferenceStore(_preferenceStore);
}
public void dispose() {
save(true); // complete save
for (Project project : _projects.values()) {
if (project != null) {
project.dispose();
}
}
_projects.clear();
_projectsMetadata.clear();
}
/**
* Registers the project in the memory of the current session
* @param project
* @param projectMetadata
*/
public void registerProject(Project project, ProjectMetadata projectMetadata) {
synchronized (this) {
_projects.put(project.id, project);
_projectsMetadata.put(project.id, projectMetadata);
}
}
/**
* Load project metadata from data storage
* @param projectID
* @return
*/
public abstract boolean loadProjectMetadata(long projectID);
/**
* Loads a project from the data store into memory
* @param id
* @return
*/
protected abstract Project loadProject(long id);
/**
* Import project from a Refine archive
* @param projectID
* @param inputStream
* @param gziped
* @throws IOException
*/
public abstract void importProject(long projectID, InputStream inputStream, boolean gziped) throws IOException;
/**
* Export project to a Refine archive
* @param projectId
* @param tos
* @throws IOException
*/
public abstract void exportProject(long projectId, TarOutputStream tos) throws IOException;
/**
* Saves a project and its metadata to the data store
* @param id
*/
public void ensureProjectSaved(long id) {
synchronized(this){
ProjectMetadata metadata = this.getProjectMetadata(id);
if (metadata != null) {
try {
saveMetadata(metadata, id);
} catch (Exception e) {
e.printStackTrace();
}
}//FIXME what should be the behaviour if metadata is null? i.e. not found
Project project = getProject(id);
if (project != null && metadata != null && metadata.getModified().after(project.getLastSave())) {
try {
saveProject(project);
} catch (Exception e) {
e.printStackTrace();
}
}//FIXME what should be the behaviour if project is null? i.e. not found or loaded.
//FIXME what should happen if the metadata is found, but not the project? or vice versa?
}
}
/**
* Save project metadata to the data store
* @param metadata
* @param projectId
* @throws Exception
*/
protected abstract void saveMetadata(ProjectMetadata metadata, long projectId) throws Exception;
/**
* Save project to the data store
* @param project
* @throws IOException
*/
protected abstract void saveProject(Project project) throws IOException;
/**
* Save workspace and all projects to data store
* @param allModified
*/
public void save(boolean allModified) {
if (allModified || _busy == 0) {
saveProjects(allModified);
saveWorkspace();
}
}
/**
* Saves the workspace to the data store
*/
protected abstract void saveWorkspace();
/**
* A utility class to prioritize projects for saving, depending on how long ago
* they have been changed but have not been saved.
*/
static protected class SaveRecord {
final Project project;
final long overdue;
SaveRecord(Project project, long overdue) {
this.project = project;
this.overdue = overdue;
}
}
/**
* Saves all projects to the data store
* @param allModified
*/
protected void saveProjects(boolean allModified) {
List<SaveRecord> records = new ArrayList<SaveRecord>();
Date startTimeOfSave = new Date();
synchronized (this) {
for (long id : _projectsMetadata.keySet()) {
ProjectMetadata metadata = getProjectMetadata(id);
Project project = _projects.get(id); // don't call getProject() as that will load the project.
if (project != null) {
boolean hasUnsavedChanges =
metadata.getModified().getTime() >= project.getLastSave().getTime();
// We use >= instead of just > to avoid the case where a newly created project
// has the same modified and last save times, resulting in the project not getting
// saved at all.
if (hasUnsavedChanges) {
long msecsOverdue = startTimeOfSave.getTime() - project.getLastSave().getTime();
records.add(new SaveRecord(project, msecsOverdue));
} else if (!project.getProcessManager().hasPending()
&& startTimeOfSave.getTime() - project.getLastSave().getTime() > PROJECT_FLUSH_DELAY) {
/*
* It's been a while since the project was last saved and it hasn't been
* modified. We can safely remove it from the cache to save some memory.
*/
_projects.remove(id).dispose();
}
}
}
}
if (records.size() > 0) {
Collections.sort(records, new Comparator<SaveRecord>() {
@Override
public int compare(SaveRecord o1, SaveRecord o2) {
if (o1.overdue < o2.overdue) {
return 1;
} else if (o1.overdue > o2.overdue) {
return -1;
} else {
return 0;
}
}
});
logger.info(allModified ?
"Saving all modified projects ..." :
"Saving some modified projects ..."
);
for (int i = 0;
i < records.size() &&
(allModified || (new Date().getTime() - startTimeOfSave.getTime() < QUICK_SAVE_MAX_TIME));
i++) {
try {
saveProject(records.get(i).project);
} catch (Exception e) {
e.printStackTrace();
// In case we're running low on memory, free as much as we can
disposeUnmodifiedProjects();
}
}
}
}
/**
* Flush all unmodified projects from memory.
*/
protected void disposeUnmodifiedProjects() {
synchronized (this) {
for (long id : _projectsMetadata.keySet()) {
ProjectMetadata metadata = getProjectMetadata(id);
Project project = _projects.get(id);
if (project != null && !project.getProcessManager().hasPending()
&& metadata.getModified().getTime() < project.getLastSave().getTime()) {
_projects.remove(id).dispose();
}
}
}
}
/**
* Gets the InterProjectModel from memory
*/
public InterProjectModel getInterProjectModel() {
return _interProjectModel;
}
/**
* Gets the project metadata from memory
* Requires that the metadata has already been loaded from the data store
* @param id
* @return
*/
public ProjectMetadata getProjectMetadata(long id) {
return _projectsMetadata.get(id);
}
/**
* Gets the project metadata from memory
* Requires that the metadata has already been loaded from the data store
* @param name
* @return
*/
public ProjectMetadata getProjectMetadata(String name) {
for (ProjectMetadata pm : _projectsMetadata.values()) {
if (pm.getName().equals(name)) {
return pm;
}
}
return null;
}
/**
* Tries to find the project id when given a project name
* Requires that all project metadata exists has been loaded to memory from the data store
* @param name
* The name of the project
* @return
* The id of the project, or -1 if it cannot be found
*/
public long getProjectID(String name) {
for (Entry<Long, ProjectMetadata> entry : _projectsMetadata.entrySet()) {
if (entry.getValue().getName().equals(name)) {
return entry.getKey();
}
}
return -1;
}
/**
* Gets all the project Metadata currently held in memory
* @return
*/
public Map<Long, ProjectMetadata> getAllProjectMetadata() {
return _projectsMetadata;
}
/**
* Gets the required project from the data store
* If project does not already exist in memory, it is loaded from the data store
* @param id
* the id of the project
* @return
* the project with the matching id, or null if it can't be found
*/
public Project getProject(long id) {
synchronized (this) {
if (_projects.containsKey(id)) {
return _projects.get(id);
} else {
Project project = loadProject(id);
if (project != null) {
_projects.put(id, project);
}
return project;
}
}
}
/**
* Gets the preference store
* @return
*/
public PreferenceStore getPreferenceStore() {
return _preferenceStore;
}
/**
* Gets all expressions from the preference store
* @return
*/
public List<String> getExpressions() {
return ((TopList) _preferenceStore.get("scripting.expressions")).getList();
}
/**
* The history entry manager deals with changes
* @return manager for handling history
*/
public abstract HistoryEntryManager getHistoryEntryManager();
/**
* Remove the project from the data store
* @param project
*/
public void deleteProject(Project project) {
deleteProject(project.id);
}
/**
* Remove project from data store
* @param projectID
*/
public abstract void deleteProject(long projectID);
/**
* Removes project from memory
* @param projectID
*/
protected void removeProject(long projectID){
if (_projects.containsKey(projectID)) {
_projects.remove(projectID).dispose();
}
if (_projectsMetadata.containsKey(projectID)) {
_projectsMetadata.remove(projectID);
}
}
/**
* Sets the flag for long running operations. This will prevent
* workspace saves from happening while it's set.
* @param busy
*/
public void setBusy(boolean busy) {
synchronized (this) {
if (busy) {
_busy++;
} else {
_busy--;
}
}
}
/**
* Add the latest expression to the preference store
* @param s
*/
public void addLatestExpression(String s) {
synchronized (this) {
((TopList) _preferenceStore.get("scripting.expressions")).add(s);
}
}
/**
*
* @param ps
*/
static protected void preparePreferenceStore(PreferenceStore ps) {
ps.put("scripting.expressions", new TopList(s_expressionHistoryMax));
ps.put("scripting.starred-expressions", new TopList(Integer.MAX_VALUE));
}
}