com.redhat.lightblue.assoc.ep.Project Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of lightblue-core-crud Show documentation
There is a newer version: 2.18.0
/*
 Copyright 2013 Red Hat, Inc. and/or its affiliates.

 This file is part of lightblue.

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see .
 */
package com.redhat.lightblue.assoc.ep;

import java.util.stream.Stream;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;

import com.redhat.lightblue.eval.Projector;
import com.redhat.lightblue.query.Projection;

/**
 * Projects the result
 */
public class Project extends Step {

    private final Projector p;
    private final Projection projection;
    private final Source source;

    public Project(ExecutionBlock block, Source source, Projection projection) {
        super(block);
        this.source = source;
        this.projection = projection;
        this.p = Projector.getInstance(projection, block.getMetadata());
    }

    @Override
    public StepResult getResults(ExecutionContext ctx) {
        return new StepResultWrapper(source.getStep().getResults(ctx)) {
            @Override
            public Stream stream() {
                return super.stream().map(doc -> new ResultDocument(p.project(doc.getDoc(), JsonNodeFactory.instance), doc));
            }
        };
    }

    @Override
    public JsonNode toJson() {
        ObjectNode o = JsonNodeFactory.instance.objectNode();
        o.set("project", projection.toJson());
        o.set("source", source.getStep().toJson());
        return o;
    }

    @Override
    public JsonNode explain(ExecutionContext ctx) {
        ObjectNode o = JsonNodeFactory.instance.objectNode();
        o.set("project", projection.toJson());
        o.set("source", source.getStep().explain(ctx));
        return o;
    }

}