org.apache.crunch.impl.mr.plan.NodePath.java Source code

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Here is the source code for org.apache.crunch.impl.mr.plan.NodePath.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * 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
 * "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 org.apache.crunch.impl.mr.plan;

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

import org.apache.crunch.impl.dist.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(stage);
    }

    public NodePath close(PCollectionImpl<?> head) {
        this.path.push(head);
        return this;
    }

    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;
    }

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