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1   // ******************************************************************************
2   //
3   // Title:       Force Field X.
4   // Description: Force Field X - Software for Molecular Biophysics.
5   // Copyright:   Copyright (c) Michael J. Schnieders 2001-2024.
6   //
7   // This file is part of Force Field X.
8   //
9   // Force Field X is free software; you can redistribute it and/or modify it
10  // under the terms of the GNU General Public License version 3 as published by
11  // the Free Software Foundation.
12  //
13  // Force Field X is distributed in the hope that it will be useful, but WITHOUT
14  // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15  // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16  // details.
17  //
18  // You should have received a copy of the GNU General Public License along with
19  // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
20  // Place, Suite 330, Boston, MA 02111-1307 USA
21  //
22  // Linking this library statically or dynamically with other modules is making a
23  // combined work based on this library. Thus, the terms and conditions of the
24  // GNU General Public License cover the whole combination.
25  //
26  // As a special exception, the copyright holders of this library give you
27  // permission to link this library with independent modules to produce an
28  // executable, regardless of the license terms of these independent modules, and
29  // to copy and distribute the resulting executable under terms of your choice,
30  // provided that you also meet, for each linked independent module, the terms
31  // and conditions of the license of that module. An independent module is a
32  // module which is not derived from or based on this library. If you modify this
33  // library, you may extend this exception to your version of the library, but
34  // you are not obligated to do so. If you do not wish to do so, delete this
35  // exception statement from your version.
36  //
37  // ******************************************************************************
38  
39  package ffx.potential.parsers;
40  
41  import static java.lang.Double.parseDouble;
42  import static java.lang.Integer.parseInt;
43  
44  import java.io.BufferedReader;
45  import java.io.File;
46  import java.io.FileReader;
47  import java.io.IOException;
48  import javax.swing.filechooser.FileFilter;
49  import org.apache.commons.io.FilenameUtils;
50  
51  /**
52   * The PDBFileFilter class is used to choose a Protein Databank (*.PDB) file.
53   *
54   * @author Michael J. Schnieders
55   * @since 1.0
56   */
57  public final class PDBFileFilter extends FileFilter {
58  
59    /** Public Constructor. */
60    public PDBFileFilter() {}
61  
62    /**
63     * This is a static version of the accept method.
64     *
65     * <p>This method return <code>true</code> if the file is a directory or Protein Databank File
66     * (*.PDB).
67     *
68     * @param file The File to examine.
69     * @return Returns true if this a PDB file.
70     */
71    public static boolean isPDB(File file) {
72      return new PDBFileFilter().accept(file);
73    }
74  
75    /**
76     * {@inheritDoc}
77     *
78     * <p>This method return <code>true</code> if the file is a directory or Protein Databank File
79     * (*.PDB).
80     */
81    @Override
82    public boolean accept(File file) {
83      if (file.isDirectory()) {
84        return true;
85      }
86      String ext = FilenameUtils.getExtension(file.getName());
87      return ext.toUpperCase().startsWith("PDB");
88    }
89  
90    /**
91     * acceptDeep Accepts a PDB file if it finds at least one parseable ATOM line.
92     *
93     * @param file a {@link java.io.File} object.
94     * @return Whether a valid PDB file.
95     */
96    public boolean acceptDeep(File file) {
97      try {
98        if (file == null || file.isDirectory() || !file.canRead()) {
99          return false;
100       }
101       try (BufferedReader br = new BufferedReader(new FileReader(file))) {
102         if (!br.ready()) {
103           return false;
104         }
105         String line = br.readLine();
106         if (line != null) {
107           line = line.trim();
108         } else {
109           return false;
110         }
111         while (line != null) {
112           line = line.trim();
113           if (line.startsWith("ATOM  ") || line.startsWith("HETATM")) {
114             try {
115               parseInt(line.substring(6, 11).trim());
116               parseInt(line.substring(22, 26).trim());
117               String[] coordOccTempVals = line.substring(30, 66).trim().split(" +");
118               for (String value : coordOccTempVals) {
119                 parseDouble(value);
120               }
121               return true;
122             } catch (NumberFormatException | StringIndexOutOfBoundsException ex) {
123               // Do nothing.
124             }
125           }
126           line = br.readLine();
127         }
128       }
129     } catch (IOException e) {
130       return false;
131     }
132     return false;
133   }
134 
135   /**
136    * {@inheritDoc}
137    *
138    * <p>Provides a description of the PDBFileFilter.
139    */
140   @Override
141   public String getDescription() {
142     return "Protein Databank (*.PDB)";
143   }
144 }