java/pig-galago/src/com/yahoo/pig/impl/logicalLayer/LogicalOperator.java

   1 /*
   2  * Copyright (c) 2007 Yahoo! Inc.  All rights reserved.
   3  * See accompanying LICENSE file.
   4  */
   5 package com.yahoo.pig.impl.logicalLayer;
   6
   7 import java.util.LinkedList;
   8 import java.util.List;
   9
  10 import com.yahoo.pig.impl.PigContext;
  11 import com.yahoo.pig.impl.logicalLayer.schema.SchemaItem;
  12 import com.yahoo.pig.impl.logicalLayer.schema.SchemaItemList;
  13
  14 abstract public class LogicalOperator {
  15     public String            alias                = null;
  16
  17     public static final int  FIXED                = 1;
  18     public static final int  MONOTONE             = 2;
  19     public static final int  UPDATABLE            = 3;   // Reserved for future use
  20     public static final int  AMENDABLE            = 4;
  21
  22     public LogicalOperator[] inputs;
  23     public int               requestedParallelism = -1;
  24     public SchemaItemList    schema               = null;
  25     public PigContext pigContext;
  26
  27     protected LogicalOperator(PigContext pigContext) {
  28         this.pigContext = pigContext;
  29     }
  30
  31     public abstract SchemaItemList outputSchema();
  32
  33     public String name() {
  34         return "ROOT";
  35     }
  36
  37     public LogicalOperator[] children() {
  38         return inputs;
  39     }
  40
  41     public String arguments() {
  42         return "";
  43     }
  44
  45     public List<String> getFuncs() {
  46         List<String> funcs = new LinkedList<String>();
  47         for (int i = 0; i < inputs.length; i++) {
  48             funcs.addAll(inputs[i].getFuncs());
  49         }
  50         return funcs;
  51     }
  52
  53     public abstract int getOutputType();
  54 }