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The NetCDF-Java Library is a Java interface to NetCDF files, as well as to many other types of scientific data formats.
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/*
 * Copyright 1998-2014 University Corporation for Atmospheric Research/Unidata
 *
 *   Portions of this software were developed by the Unidata Program at the
 *   University Corporation for Atmospheric Research.
 *
 *   Access and use of this software shall impose the following obligations
 *   and understandings on the user. The user is granted the right, without
 *   any fee or cost, to use, copy, modify, alter, enhance and distribute
 *   this software, and any derivative works thereof, and its supporting
 *   documentation for any purpose whatsoever, provided that this entire
 *   notice appears in all copies of the software, derivative works and
 *   supporting documentation.  Further, UCAR requests that the user credit
 *   UCAR/Unidata in any publications that result from the use of this
 *   software or in any product that includes this software. The names UCAR
 *   and/or Unidata, however, may not be used in any advertising or publicity
 *   to endorse or promote any products or commercial entity unless specific
 *   written permission is obtained from UCAR/Unidata. The user also
 *   understands that UCAR/Unidata is not obligated to provide the user with
 *   any support, consulting, training or assistance of any kind with regard
 *   to the use, operation and performance of this software nor to provide
 *   the user with any updates, revisions, new versions or "bug fixes."
 *
 *   THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
 *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *   DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
 *   INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 *   FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 *   WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
 */
package ucar.nc2.ft.point;

import ucar.nc2.ft.*;
import ucar.ma2.StructureData;
import ucar.ma2.StructureDataIterator;

import java.io.IOException;

/**
 * A PointFeatureIterator which uses a StructureDataIterator to iterate over members of a Structure,
 * with optional filtering and calculation of time range and bounding box.
 * 
 * Subclass must implement makeFeature() to turn the StructureData into a PointFeature.
 *
 * @author caron
 * @since Feb 29, 2008
 */
public abstract class PointIteratorFromStructureData extends PointIteratorAbstract {

  // makeFeature may return null, if so then skip it and go to next iteration
  protected abstract PointFeature makeFeature(int recnum, StructureData sdata) throws IOException;

  private PointFeatureIterator.Filter filter;
  private StructureDataIterator structIter;
  private PointFeature feature = null; // hasNext must cache
  private boolean finished = false;

  /**
   * Constructor
   * @param structIter  original iterator
   * @param filter      optional filter
   * @throws IOException
   */
  public PointIteratorFromStructureData(StructureDataIterator structIter, PointFeatureIterator.Filter filter) throws IOException {
    this.structIter = structIter;
    this.filter = filter;
  }

  public boolean hasNext() throws IOException {

    while (true) {
      StructureData sdata = nextStructureData();
      if (sdata == null) break;
      feature = makeFeature(structIter.getCurrentRecno(), sdata);
      if (feature == null) continue;
      if (feature.getLocation().isMissing()) {
        continue;
      }
      if (filter == null || filter.filter(feature))
        return true;
    }

    // all done
    feature = null;
    finish();
    return false;
  }

  public PointFeature next() throws IOException {
    if (feature == null) return null;
    calcBounds(feature);
    return feature;
  }

  public void setBufferSize(int bytes) {
    structIter.setBufferSize(bytes);
  }

  public void finish() {
    if (finished) return;
    finishCalcBounds();
    finished = true;
    structIter.finish();
  }

  private StructureData nextStructureData() throws IOException {
    return structIter.hasNext() ? structIter.next() : null;
  }

}