what to write here

what to write here

https://github.com/apache/incubator-wayang/blob/3a461b516bda004c2fa7d6d4392ed0ee23da96cf/wayang-platforms/wayang-java/src/main/java/org/apache/wayang/java/operators/JavaGoogleCloudStorageSource.java#L80

```java

/*
* 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.wayang.java.operators;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.stream.Stream;

import org.apache.wayang.basic.operators.AmazonS3Source;
import org.apache.wayang.basic.operators.GoogleCloudStorageSource;
import org.apache.wayang.core.api.exception.WayangException;
import org.apache.wayang.core.optimizer.OptimizationContext;
import org.apache.wayang.core.optimizer.OptimizationContext.OperatorContext;
import org.apache.wayang.core.optimizer.costs.LoadProfileEstimators;
import org.apache.wayang.core.platform.ChannelDescriptor;
import org.apache.wayang.core.platform.ChannelInstance;
import org.apache.wayang.core.platform.lineage.ExecutionLineageNode;
import org.apache.wayang.core.util.Tuple;
import org.apache.wayang.java.channels.StreamChannel;
import org.apache.wayang.java.execution.JavaExecutor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class JavaGoogleCloudStorageSource extends GoogleCloudStorageSource implements JavaExecutionOperator {
private static final Logger logger = LoggerFactory.getLogger(JavaGoogleCloudStorageSource.class);

public JavaGoogleCloudStorageSource(String bucket, String blobName, String filePathToCredentialsFile) {
super(bucket, blobName, filePathToCredentialsFile);
}

public JavaGoogleCloudStorageSource(GoogleCloudStorageSource that) {
super(that);
}

@Override
public Tuple, Collection> evaluate(ChannelInstance[] inputs,
ChannelInstance[] outputs, JavaExecutor javaExecutor, OperatorContext operatorContext) {
assert inputs.length == this.getNumInputs();
assert outputs.length == this.getNumOutputs();

try {

BufferedReader buffereadReder = new BufferedReader(new InputStreamReader(super.getInputStream()));
Stream lines = buffereadReder.lines();
((StreamChannel.Instance) outputs[0]).accept(lines);
}
catch (Exception e) {
throw new WayangException("Failed to read file from Google CLoud storage with error", e);
}

//TODO what to write here
ExecutionLineageNode prepareLineageNode = new ExecutionLineageNode(operatorContext);
prepareLineageNode.add(LoadProfileEstimators.createFromSpecification(
//TODO what to write here

"wayang.java.googlecloudstoragesource.load.prepare", javaExecutor.getConfiguration()
));
ExecutionLineageNode mainLineageNode = new ExecutionLineageNode(operatorContext);
mainLineageNode.add(LoadProfileEstimators.createFromSpecification(
//TODO what to write here

"wayang.java.googlecloudstoragesource.load.main", javaExecutor.getConfiguration()
));

outputs[0].getLineage().addPredecessor(mainLineageNode);

return prepareLineageNode.collectAndMark();
}

@Override
public Collection getLoadProfileEstimatorConfigurationKeys() {
return Arrays.asList("wayang.java.googlecloudstoragesource.load.prepare", "wayang.java.googlecloudstoragesource.load.main");
}

@Override
public JavaGoogleCloudStorageSource copy() {
return new JavaGoogleCloudStorageSource(this.getBucket(), this.getBlobName(), this.getfilePathToCredentialsFile());
}

@Override
public List getSupportedInputChannels(int index) {
throw new UnsupportedOperationException(String.format("%s does not have input channels.", this));
}

@Override
public List getSupportedOutputChannels(int index) {
assert index <= this.getNumOutputs() || (index == 0 && this.getNumOutputs() == 0);
return Collections.singletonList(StreamChannel.DESCRIPTOR);
}

}

```

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