import storm.trident.planner.processor.ProjectedProcessor; //导入依赖的package包/类
public Stream project(Fields keepFields) {
    projectionValidation(keepFields);
    return _topology.addSourcedNode(this, new ProcessorNode(_topology.getUniqueStreamId(), _name, keepFields, new Fields(), new ProjectedProcessor(keepFields)));
}
 

import storm.trident.planner.processor.ProjectedProcessor; //导入依赖的package包/类
public Stream project(Fields keepFields) {
    projectionValidation(keepFields);
    return _topology.addSourcedNode(this, new ProcessorNode(_topology.getUniqueStreamId(), _name, keepFields, new Fields(), new ProjectedProcessor(
            keepFields)));
}
 

import storm.trident.planner.processor.ProjectedProcessor; //导入依赖的package包/类
/**
 * Filters out fields from a stream, resulting in a Stream containing only the fields specified by `keepFields`.
 *
 * For example, if you had a Stream `mystream` containing the fields `["a", "b", "c","d"]`, calling"
 *
 * ```java
 * mystream.project(new Fields("b", "d"))
 * ```
 *
 * would produce a stream containing only the fields `["b", "d"]`.
 *
 *
 * @param keepFields The fields in the Stream to keep
 * @return
 */
public Stream project(Fields keepFields) {
    projectionValidation(keepFields);
    return _topology.addSourcedNode(this, new ProcessorNode(_topology.getUniqueStreamId(), _name, keepFields, new Fields(), new ProjectedProcessor(keepFields)));
}