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

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* 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
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* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
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* 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);
}

}

```

39fdb3633cae1e43c5b21d4ff3e1606aa0614625

Start with wayang-platforms/wayang-java/src/main/java/org/apache/wayang/java/operators/JavaGoogleCloudStorageSource.java at the referenced TODOs, then inspect related Java source operators and their load-profile configuration. Determine what the prepare and main lineage entries require, and verify that the Google Cloud Storage source evaluates successfully with correct lineage handling.

Written by the indexing model from the issue text.