NullIf.java

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 * Pentaho Data Integration
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 * Copyright (C) 2002-2017 by Pentaho : http://www.pentaho.com
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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with
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 *    http://www.apache.org/licenses/LICENSE-2.0
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package org.pentaho.di.trans.steps.nullif;

import org.pentaho.di.core.exception.KettleException;
import org.pentaho.di.core.row.ValueMetaInterface;
import org.pentaho.di.core.row.value.ValueMetaString;
import org.pentaho.di.i18n.BaseMessages;
import org.pentaho.di.trans.Trans;
import org.pentaho.di.trans.TransMeta;
import org.pentaho.di.trans.step.BaseStep;
import org.pentaho.di.trans.step.StepDataInterface;
import org.pentaho.di.trans.step.StepInterface;
import org.pentaho.di.trans.step.StepMeta;
import org.pentaho.di.trans.step.StepMetaInterface;

/**
 * NullIf step, put null as value when the original field matches a specific value.
 *
 * @author Matt
 * @since 4-aug-2003
 */
public class NullIf extends BaseStep implements StepInterface {
  private static Class<?> PKG = NullIfMeta.class; // for i18n purposes, needed by Translator2!!

  private NullIfMeta meta;
  private NullIfData data;

  public NullIf( StepMeta stepMeta, StepDataInterface stepDataInterface, int copyNr, TransMeta transMeta,
    Trans trans ) {
    super( stepMeta, stepDataInterface, copyNr, transMeta, trans );
  }

  @Override
  public boolean processRow( StepMetaInterface smi, StepDataInterface sdi ) throws KettleException {
    meta = (NullIfMeta) smi;
    data = (NullIfData) sdi;

    // Get one row from one of the rowsets...
    Object[] r = getRow();

    if ( r == null ) { // no more input to be expected...

      setOutputDone();
      return false;
    }

    if ( first ) {
      first = false;
      data.outputRowMeta = getInputRowMeta().clone();
      int fieldsLength = meta.getFields().length;
      data.keynr = new int[fieldsLength];
      data.nullValue = new Object[fieldsLength];
      data.nullValueMeta = new ValueMetaInterface[fieldsLength];
      for ( int i = 0; i < fieldsLength; i++ ) {
        data.keynr[i] = data.outputRowMeta.indexOfValue( meta.getFields()[i].getFieldName() );
        if ( data.keynr[i] < 0 ) {
          logError( BaseMessages.getString( PKG, "NullIf.Log.CouldNotFindFieldInRow", meta.getFields()[i].getFieldName() ) );
          setErrors( 1 );
          stopAll();
          return false;
        }
        data.nullValueMeta[i] = data.outputRowMeta.getValueMeta( data.keynr[i] );
        // convert from input string entered by the user
        ValueMetaString vms = new ValueMetaString();
        vms.setConversionMask( data.nullValueMeta[i].getConversionMask() );
        data.nullValue[i] =
          data.nullValueMeta[i].convertData( vms, meta.getFields()[i].getFieldValue() );
      }
    }

    if ( log.isRowLevel() ) {
      logRowlevel( BaseMessages.getString( PKG, "NullIf.Log.ConvertFieldValuesToNullForRow" )
        + data.outputRowMeta.getString( r ) );
    }

    for ( int i = 0; i < meta.getFields().length; i++ ) {
      Object field = r[data.keynr[i]];
      if ( field != null && data.nullValueMeta[i].compare( field, data.nullValue[i] ) == 0 ) {
        // OK, this value needs to be set to NULL
        r[data.keynr[i]] = null;
      }
    }

    putRow( data.outputRowMeta, r ); // Just one row!

    return true;
  }

  @Override
  public void dispose( StepMetaInterface smi, StepDataInterface sdi ) {
    meta = (NullIfMeta) smi;
    data = (NullIfData) sdi;

    super.dispose( smi, sdi );
  }

  @Override
  public boolean init( StepMetaInterface smi, StepDataInterface sdi ) {
    meta = (NullIfMeta) smi;
    data = (NullIfData) sdi;

    if ( super.init( smi, sdi ) ) {
      // Add init code here.
      return true;
    }
    return false;
  }

}