harp.script.node.NodeContextBuilder.java Source code

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Here is the source code for harp.script.node.NodeContextBuilder.java

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/*
 * Copyright 2014 Yash Parghi
 *
 * Licensed 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 harp.script.node;

import com.google.common.base.Preconditions;
import harp.node.NodeSpec;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * A builder for assembling a NodeContext in the course of evaluating a node.harp script.
 */
public final class NodeContextBuilder {

    private final Set<String> nodeNames;
    private final List<NodeSpec> nodes;

    public NodeContextBuilder() {
        this.nodeNames = new HashSet<>();
        this.nodes = new ArrayList<>();
    }

    void addNode(NodeSpec nodeSpec) {
        Preconditions.checkNotNull(nodeSpec.getName(), "A NodeSpec must have a non-null name.");
        Preconditions.checkState(!nodeNames.contains(nodeSpec.getName()),
                "A NodeSpec named %s has already been declared.", nodeSpec.getName());
        nodeNames.add(nodeSpec.getName());
        nodes.add(nodeSpec);
    }

    NodeContext build() {
        return new NodeContext(nodes);
    }
}