src/org/apache/pig/impl/logicalLayer/LOUnion.java

/*
 * 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.pig.impl.logicalLayer;

import java.util.List;
import java.util.Map;

import org.apache.pig.impl.logicalLayer.schema.TupleSchema;



public class LOUnion extends LogicalOperator {
    private static final long serialVersionUID = 1L;

    public LOUnion(Map<OperatorKey, LogicalOperator> opTable,
                   String scope, 
                   long id, 
                   List<OperatorKey> inputsIn) {
        super(opTable, scope, id, inputsIn);
    }
    
    @Override
    public String name() {
        StringBuilder sb = new StringBuilder();
        sb.append("Union ");
        sb.append(scope);
        sb.append("-");
        sb.append(id);
        return sb.toString();
    }

    @Override
    public TupleSchema outputSchema() {
        if (schema == null) {
            TupleSchema longest = opTable.get(getInputs().get(0)).outputSchema();
            int current = 0;
          for (OperatorKey opKey: getInputs()) {
              LogicalOperator lo = opTable.get(opKey);
              
              if (lo != null && lo.outputSchema() != null && 
                  lo.outputSchema().numFields() > current) {
                  longest = lo.outputSchema();
                  current = longest.numFields();
                }
            }
            schema = longest.copy();
        }

        schema.setAlias(alias);
        return schema;
    }

    @Override
    public int getOutputType() {
        int outputType = FIXED;
        for (int i = 0; i < getInputs().size(); i++) {
            switch (opTable.get(getInputs().get(i)).getOutputType()) {
            case FIXED:
                continue;
            case MONOTONE:
                if (outputType == FIXED)
                    outputType = MONOTONE;
                continue;
            case AMENDABLE:
                outputType = AMENDABLE;
            default:
                throw new
                    RuntimeException
                    ("Invalid input type to the UNION operator");
            }
        }
        return outputType;
    }

    public void visit(LOVisitor v) {
        v.visitUnion(this);
    }
}