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Added TripleReader and TripleWriter modules to read and write triples
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1 parent a797c03 commit 969a803

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+209
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4 files changed

+209
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‎src/main/java/org/culturegraph/mf/stream/sink/TripleWriter.java

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/*
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* Copyright 2013 Deutsche Nationalbibliothek
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*
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* Licensed under the Apache License, Version 2.0 the "License";
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.culturegraph.mf.stream.sink;
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import java.io.BufferedOutputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.ObjectOutputStream;
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import org.culturegraph.mf.exceptions.MetafactureException;
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import org.culturegraph.mf.framework.DefaultObjectReceiver;
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import org.culturegraph.mf.types.Triple;
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/**
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* @author Christoph Böhme
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*
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*/
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public final class TripleWriter extends DefaultObjectReceiver<Triple> {
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public static final int BUFFERSIZE = 2048;
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private final String filename;
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private ObjectOutputStream outputStream;
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public TripleWriter(final String filename) {
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this.filename = filename;
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resetStream();
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}
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@Override
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public void process(final Triple obj) {
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try {
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obj.write(outputStream);
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} catch (IOException e) {
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throw new MetafactureException(e);
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}
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}
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@Override
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public void resetStream() {
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try {
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if (outputStream != null) {
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outputStream.close();
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}
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outputStream = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(filename), BUFFERSIZE));
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} catch (IOException e) {
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throw new MetafactureException(e);
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}
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}
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@Override
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public void closeStream() {
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try {
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if (outputStream != null) {
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outputStream.close();
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}
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} catch (IOException e) {
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throw new MetafactureException(e);
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}
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}
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}

‎src/main/java/org/culturegraph/mf/stream/source/TripleReader.java

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/*
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* Copyright 2013 Deutsche Nationalbibliothek
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*
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* Licensed under the Apache License, Version 2.0 the "License";
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.culturegraph.mf.stream.source;
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import java.io.BufferedInputStream;
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import java.io.EOFException;
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import java.io.FileInputStream;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import org.culturegraph.mf.exceptions.MetafactureException;
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import org.culturegraph.mf.framework.DefaultObjectPipe;
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import org.culturegraph.mf.framework.ObjectReceiver;
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import org.culturegraph.mf.types.Triple;
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/**
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* @author Christoph Böhme
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*
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*/
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public final class TripleReader extends
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DefaultObjectPipe<String, ObjectReceiver<Triple>> {
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public static final int BUFFERSIZE = 2048;
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@Override
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public void process(final String filename) {
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try {
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final ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(new FileInputStream(filename), BUFFERSIZE));
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try {
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while (true) {
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getReceiver().process(Triple.read(in));
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}
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} catch (EOFException e) {
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} finally {
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in.close();
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}
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} catch (IOException e) {
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throw new MetafactureException(e);
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}
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}
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}

‎src/main/java/org/culturegraph/mf/types/Triple.java

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@@ -19,6 +19,8 @@
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import org.culturegraph.mf.exceptions.ShouldNeverHappenException;
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/**
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* Stores an immutable name-value-pair. The hash code is precomputed during
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* instantiation.
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}
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public static Triple read(final ObjectInputStream in) throws IOException {
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return new Triple(in.readUTF(), in.readUTF(), in.readUTF());
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try {
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return new Triple(in.readUTF(), in.readUTF(), in.readUTF(), (ObjectType) in.readObject());
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} catch (ClassNotFoundException e) {
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throw new ShouldNeverHappenException(e);
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}
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}
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public void write(final ObjectOutputStream out) throws IOException {
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out.writeUTF(subject);
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out.writeUTF(predicate);
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out.writeUTF(object);
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out.writeObject(objectType);
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}
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@Override

‎src/test/java/org/culturegraph/mf/stream/sink/TripleReaderWriterTest.java

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/*
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* Copyright 2013 Deutsche Nationalbibliothek
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*
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* Licensed under the Apache License, Version 2.0 the "License";
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.culturegraph.mf.stream.sink;
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import static org.mockito.Mockito.verify;
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import java.io.File;
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import java.io.IOException;
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import org.culturegraph.mf.framework.ObjectReceiver;
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import org.culturegraph.mf.stream.source.TripleReader;
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import org.culturegraph.mf.types.Triple;
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import org.culturegraph.mf.types.Triple.ObjectType;
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import org.junit.Rule;
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import org.junit.Test;
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import org.junit.rules.TemporaryFolder;
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import org.mockito.Mock;
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import org.mockito.MockitoAnnotations;
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/**
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* @author Christoph Böhme
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*
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*/
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public final class TripleReaderWriterTest {
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private static final Triple TRIPLE1 = new Triple("S", "P", "O1");
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private static final Triple TRIPLE2 = new Triple("S", "P", "O2", ObjectType.ENTITY);
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// NO CHECKSTYLE VisibilityModifier FOR 3 LINES:
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// JUnit requires rules to be public
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@Rule
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public TemporaryFolder tempFolder = new TemporaryFolder();
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@Mock
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private ObjectReceiver<Triple> receiver;
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@Test
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public void testShouldWriteAndReadTriples() throws IOException {
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MockitoAnnotations.initMocks(this);
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final File file = tempFolder.newFile();
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final TripleWriter tripleWriter = new TripleWriter(file.getAbsolutePath());
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final TripleReader tripleReader = new TripleReader();
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tripleReader.setReceiver(receiver);
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tripleWriter.process(TRIPLE1);
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tripleWriter.process(TRIPLE2);
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tripleWriter.closeStream();
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tripleReader.process(file.getAbsolutePath());
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verify(receiver).process(TRIPLE1);
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verify(receiver).process(TRIPLE2);
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}
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}

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