com.cloudera.crunch.impl.mr.plan.NodePath.java Source code

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Here is the source code for com.cloudera.crunch.impl.mr.plan.NodePath.java

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/**
 * Copyright (c) 2011, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. 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
 *
 * This software 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 com.cloudera.crunch.impl.mr.plan;

import java.util.Iterator;
import java.util.LinkedList;

import com.cloudera.crunch.impl.mr.collect.PCollectionImpl;
import com.google.common.collect.Lists;

class NodePath implements Iterable<PCollectionImpl> {
    private LinkedList<PCollectionImpl> path;

    public NodePath() {
        this.path = Lists.newLinkedList();
    }

    public NodePath(PCollectionImpl tail) {
        this.path = Lists.newLinkedList();
        this.path.add(tail);
    }

    public NodePath(NodePath other) {
        this.path = Lists.newLinkedList(other.path);
    }

    public void push(PCollectionImpl stage) {
        this.path.push((PCollectionImpl) stage);
    }

    public void close(PCollectionImpl head) {
        this.path.push(head);
    }

    public Iterator<PCollectionImpl> iterator() {
        return path.iterator();
    }

    public Iterator<PCollectionImpl> descendingIterator() {
        return path.descendingIterator();
    }

    public PCollectionImpl get(int index) {
        return path.get(index);
    }

    public PCollectionImpl head() {
        return path.peekFirst();
    }

    public PCollectionImpl tail() {
        return path.peekLast();
    }

    @Override
    public boolean equals(Object other) {
        if (other == null || !(other instanceof NodePath)) {
            return false;
        }
        NodePath nodePath = (NodePath) other;
        return path.equals(nodePath.path);
    }

    @Override
    public int hashCode() {
        return 17 + 37 * path.hashCode();
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for (PCollectionImpl collect : path) {
            sb.append(collect.getName() + "|");
        }
        sb.deleteCharAt(sb.length() - 1);
        return sb.toString();
    }

    public NodePath splitAt(int splitIndex, PCollectionImpl newHead) {
        NodePath top = new NodePath();
        for (int i = 0; i <= splitIndex; i++) {
            top.path.add(path.get(i));
        }
        LinkedList<PCollectionImpl> nextPath = Lists.newLinkedList();
        nextPath.add(newHead);
        nextPath.addAll(path.subList(splitIndex + 1, path.size()));
        path = nextPath;
        return top;
    }
}