/*******************************************************************************
* Copyright (c) 2006-2012
* Software Technology Group, Dresden University of Technology
* DevBoost GmbH, Berlin, Amtsgericht Charlottenburg, HRB 140026
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Software Technology Group - TU Dresden, Germany;
* DevBoost GmbH - Berlin, Germany
* - initial API and implementation
******************************************************************************/
package org.reuseware.sokan.index;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.reuseware.sokan.FacetedRequest;
import org.reuseware.sokan.FacetedResponse;
import org.reuseware.sokan.ID;
import org.reuseware.sokan.IndexRow;
import org.reuseware.sokan.index.util.CoreUtil;
import org.reuseware.sokan.index.util.RowUtil;
/**
* Caches query results from queries on the index.
*/
public class IndexCache {
/**
* Indicates that the cache was just initiated.
*/
public static final String INIT_TIME = "INIT_TIME";
private String time = INIT_TIME;
private List<IndexRow> allCache;
private Map<ID, IndexRow> oneRowCache;
private Map<Collection<ID>, List<IndexRow>> nRowCache;
private Map<FacetedRequest, FacetedResponse> rspCache;
private Map<ID, Boolean> isArtCache;
/**
* The constructor.
*/
public IndexCache() {
oneRowCache = new HashMap<ID, IndexRow>();
nRowCache = new HashMap<Collection<ID>, List<IndexRow>>();
rspCache = new HashMap<FacetedRequest, FacetedResponse>();
isArtCache = new HashMap<ID, Boolean>();
}
/**
* Puts all given rows into the cache.
*
* @param timeStamp the time stamp of the index update
* @param toCache the rows to cache
* @return true if successful
*/
public boolean putAll(String timeStamp, List<IndexRow> toCache) {
if (isNull(timeStamp, toCache)) {
return false;
}
time = timeStamp;
allCache = toCache;
return true;
}
/**
* Returns all rows associated with the given time stamp.
*
* @param timeStamp the time stamp
* @return the rows
*/
public List<IndexRow> getAll(String timeStamp) {
if (notLastCommit(timeStamp)) {
if (isWellFormed(timeStamp)) {
clearAll();
}
return null;
}
return allCache;
}
/**
* Returns the row of the artifact with the given ID and the given time stamp.
*
* @param timeStamp the time stamp
* @param id the ID
* @return the row
*/
public IndexRow getIndex(String timeStamp, ID id) {
if (notLastCommit(timeStamp)) {
if (id != null && isWellFormed(timeStamp)) {
clearAll();
}
return null;
}
IndexRow myRow = oneRowCache.get(id);
if (myRow != null) {
return myRow;
}
if (allCache != null) {
myRow = RowUtil.findRowFor(id, allCache);
if (myRow != null) {
oneRowCache.put(id, myRow);
return myRow;
}
}
return myRow;
}
/**
* Puts the given row into the cache.
*
* @param timeStamp the time stamp of the index update
* @param id the ID of the artifact
* @param toCache the row to cache
* @return true if successful
*/
public boolean putIndex(String timeStamp, ID id, IndexRow toCache) {
if (isNull(timeStamp, toCache) || id == null) {
return false;
}
time = timeStamp;
oneRowCache.put(id, toCache);
return true;
}
/**
* Returns the rows of the artifacts with the given IDs and the given time stamp.
*
* @param timeStamp the time stamp
* @param ids the IDs
* @return the rows
*/
public List<IndexRow> getIndex(String timeStamp, Collection<ID> ids) {
if (notLastCommit(timeStamp)) {
if (ids != null && isWellFormed(timeStamp)) {
clearAll();
}
return null;
}
Collection<ID> myKey = null;
for (Collection<ID> keyIDs : nRowCache.keySet()) {
if (!CoreUtil.equal(ids, keyIDs)) {
continue;
}
myKey = keyIDs;
break;
}
return nRowCache.get(myKey);
}
/**
* Puts the given rows into the cache.
*
* @param timeStamp the time stamp of the index update
* @param ids the IDs of the artifacts
* @param toCache the rows to cache
* @return true if successful
*/
public boolean putIndex(String timeStamp, Collection<ID> ids,
List<IndexRow> toCache) {
if (isNull(timeStamp, toCache) || ids == null || ids.isEmpty()) {
return false;
}
time = timeStamp;
Collection<ID> myKey = null;
for (Collection<ID> keyIDs : nRowCache.keySet()) {
if (!CoreUtil.equal(ids, keyIDs)) {
continue;
}
myKey = keyIDs;
break;
}
nRowCache.put(myKey != null ? myKey : ids, toCache);
return true;
}
/**
* @param timeStamp the time stamp
* @param req the request
* @return the cached query result
*/
public FacetedResponse getResponse(String timeStamp, FacetedRequest req) {
if (notLastCommit(timeStamp)) {
if (req != null && isWellFormed(timeStamp)) {
clearAll();
}
return null;
}
return rspCache.get(req);
}
/**
* @param timeStamp the time stamp
* @param req the request
* @param toCache the query result to cache
* @return true if successful
*/
public boolean putResponse(String timeStamp, FacetedRequest req,
FacetedResponse toCache) {
if (isNull(timeStamp, toCache) || req == null) {
return false;
}
time = timeStamp;
rspCache.put(req, toCache);
return true;
}
/**
* @param timeStamp the time stamp
* @param id the artifact ID
* @return true if there is an artifact with the given ID indexed at the given time stamp
*/
public Boolean isArtifact(String timeStamp, ID id) {
if (notLastCommit(timeStamp)) {
if (id != null && isWellFormed(timeStamp)) {
clearAll();
}
return null;
}
Boolean isArt = isArtCache.get(id);
if (isArt != null) {
return isArt;
}
if (allCache != null && RowUtil.findRowFor(id, allCache) != null) {
isArtCache.put(id, true);
return true;
}
if (RowUtil.findRowFor(id, oneRowCache.values()) != null) {
isArtCache.put(id, true);
return true;
}
for (List<IndexRow> rows : nRowCache.values()) {
if (RowUtil.findRowFor(id, rows) != null) {
isArtCache.put(id, true);
return true;
}
}
for (FacetedResponse rsp : rspCache.values()) {
if (RowUtil.findRowFor(id, rsp.getContent()) != null) {
isArtCache.put(id, true);
return true;
}
}
return null;
}
/**
* @param timeStamp the time stamp
* @param id the ID
* @param toCache value to cache
* @return true if successful
*/
public boolean putIsArtifact(String timeStamp, ID id, Boolean toCache) {
if (isNull(timeStamp, toCache) || id == null) {
return false;
}
time = timeStamp;
isArtCache.put(id, toCache);
return true;
}
private boolean notLastCommit(String timeStamp) {
return timeStamp == null || timeStamp.equals("")
|| !timeStamp.equals(time);
}
private boolean isWellFormed(String timeStamp) {
return CoreUtil.toDate(timeStamp) != null;
}
private boolean isNull(String timeStamp, Object toCache) {
return timeStamp == null || timeStamp.equals("") || toCache == null;
}
private void clearAll() {
nRowCache.clear();
allCache = null;
oneRowCache.clear();
rspCache.clear();
isArtCache.clear();
}
}