/*
* 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.clerezza.rdf.file.storage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;
import java.util.Collection;
import java.util.Iterator;
import org.apache.clerezza.rdf.core.Graph;
import org.apache.clerezza.rdf.core.NonLiteral;
import org.apache.clerezza.rdf.core.Resource;
import org.apache.clerezza.rdf.core.Triple;
import org.apache.clerezza.rdf.core.UriRef;
import org.apache.clerezza.rdf.core.impl.SimpleMGraph;
import org.apache.clerezza.rdf.core.serializedform.Parser;
import org.apache.clerezza.rdf.core.serializedform.Serializer;
import org.apache.clerezza.rdf.core.serializedform.SupportedFormat;
/**
*
* @author mir
*/
public class FileMGraph extends SimpleMGraph {
private Serializer serializer;
private File file;
private String fileType;
FileMGraph(UriRef uri, Parser parser,
Serializer serializer) {
file = new File(URI.create(uri.getUnicodeString()));
String fileEnding = extractFileEnding(uri);
fileType = getMediaTypeForFileEnding(fileEnding);
this.serializer = serializer;
try {
if (file.exists() && file.length() != 0) {
InputStream fio = new FileInputStream(file);
Graph graph = parser.parse(fio, fileType);
addAllNoFileAccess(graph);
} else {
file.createNewFile();
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public boolean add(Triple e) {
boolean result = super.add(e);
writeToFile();
return result;
}
@Override
public boolean addAll(Collection<? extends Triple> c) {
boolean modified = addAllNoFileAccess(c);
writeToFile();
return modified;
}
@Override
public boolean remove(Object o) {
Iterator<Triple> e = super.filter(null, null, null);
while (e.hasNext()) {
if (o.equals(e.next())) {
e.remove();
writeToFile();
return true;
}
}
return false;
}
@Override
public boolean removeAll(Collection<?> c) {
boolean modified = false;
Iterator<Triple> e = super.filter(null, null, null);
while (e.hasNext()) {
if (c.contains(e.next())) {
e.remove();
modified = true;
}
}
writeToFile();
return modified;
}
@Override
public boolean retainAll(Collection<?> c) {
boolean result = super.retainAll(c);
writeToFile();
return result;
}
@Override
public Iterator<Triple> filter(final NonLiteral subject,
final UriRef predicate,
final Resource object) {
final Iterator<Triple> baseIter = super.filter(subject, predicate, object);
Iterator<Triple> iterator = new Iterator<Triple>() {
@Override
public boolean hasNext() {
return baseIter.hasNext();
}
@Override
public Triple next() {
return baseIter.next();
}
@Override
public void remove() {
baseIter.remove();
writeToFile();
}
};
return iterator;
}
private boolean addAllNoFileAccess(Collection<? extends Triple> c) {
boolean modified = false;
Iterator<? extends Triple> e = c.iterator();
while (e.hasNext()) {
if (super.add(e.next())) {
modified = true;
}
}
return modified;
}
private String extractFileEnding(UriRef uri) {
String uriString = uri.getUnicodeString();
String fileEnding = uriString.substring(uriString.lastIndexOf(".") + 1, uriString.length());
return fileEnding;
}
private String getMediaTypeForFileEnding(String fileEnding) {
if (fileEnding.equals("rdf")) {
return SupportedFormat.RDF_XML;
}
if (fileEnding.equals("nt")) {
return SupportedFormat.N_TRIPLE;
}
if (fileEnding.equals("ttl")) {
return SupportedFormat.TURTLE;
}
if (fileEnding.equals("n3")) {
return SupportedFormat.N3;
}
return null;
}
private void writeToFile() {
synchronized(this) {
OutputStream out = null;
try {
out = new FileOutputStream(file);
serializer.serialize(out, this, fileType);
} catch (FileNotFoundException ex) {
throw new RuntimeException(ex);
} finally {
try {
out.close();
} catch (IOException ex) {
new RuntimeException(ex);
}
}
}
}
public void delete() {
file.delete();
}
}