content: /*
   * 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.hadoop.chukwa;
  
  import java.io.IOException;
  
  import org.apache.pig.EvalFunc;
  import org.apache.pig.data.DataType;
  import org.apache.pig.data.Tuple;
  import org.apache.pig.impl.logicalLayer.FrontendException;
  import org.apache.pig.impl.logicalLayer.schema.Schema;
  
  /**
   * string.PARSEDOUBLE implements a binding to the Java method
   * {@link java.lang.Double#parseDouble(String)}
   * 
   * <dl>
   * <dt><b>Parameters:</b></dt>
   * <dd><code>strtoconvert</code> - <code>chararray</code>
   * 
   * <dt><b>Return Value:</b></dt>
   * <dd><code>double</code> parsed value</dd>
   * 
   * <dt><b>Return Schema:</b></dt>
   * <dd>parselong: double</dd>
   * 
   * <dt><b>Example:</b></dt>
   * <dd><code>
   * register string.jar;<br/>
   * A = load 'mydata' using PigStorage() as ( stringnumber: chararray );<br/>
   * B = foreach A generate stringnumber, org.apache.hadoop.chukwa.PARSEDOUBLE(stringnumber));
   * </code></dd>
   * </dl>
   * 
   */
  public class PARSEDOUBLE extends EvalFunc<Double> {
    
    public Double exec(Tuple input) throws IOException {
      if (input == null || input.size() < 1)
        return null;
      try {
        String strtoconvert = input.get(0).toString();
        Double number = Double.parseDouble(strtoconvert);
  
        return number;
      } catch (Exception e) {
        return null;
      }
    }
  
    @Override
    public Schema outputSchema(Schema input) {
      Schema schema = null;
      try {
        schema = new Schema(new Schema.FieldSchema(input.getField(0).alias, DataType.DOUBLE));
      } catch (FrontendException e) {
        schema = new Schema(new Schema.FieldSchema(getSchemaName("parseDouble", input),
            DataType.DOUBLE));
      }
      return schema;
    }
  }
  