001/* 002 * BioJava development code 003 * 004 * This code may be freely distributed and modified under the 005 * terms of the GNU Lesser General Public Licence. This should 006 * be distributed with the code. If you do not have a copy, 007 * see: 008 * 009 * http://www.gnu.org/copyleft/lesser.html 010 * 011 * Copyright for this code is held jointly by the individual 012 * authors. These should be listed in @author doc comments. 013 * 014 * For more information on the BioJava project and its aims, 015 * or to join the biojava-l mailing list, visit the home page 016 * at: 017 * 018 * http://www.biojava.org/ 019 * 020 */ 021 022package org.biojavax.bio.db.biosql; 023 024import java.lang.reflect.InvocationTargetException; 025import java.lang.reflect.Method; 026import java.util.Collections; 027import java.util.Map; 028 029import org.biojava.bio.seq.Feature; 030 031/** 032 * The class that accepts no features. 033 * <p> 034 * Use the FeatureFilter.none member. 035 * 036 * @author Matthew Pocock 037 * @author Richard Holland 038 * @since 1.5 039 */ 040public class BioSQLAcceptNoneFilter implements BioSQLFeatureFilter { 041 private Method isNull; 042 043 protected BioSQLAcceptNoneFilter() { 044 super(); 045 try { 046 // Lazy load the Restrictions class. 047 Class restrictions = Class.forName("org.hibernate.criterion.Restrictions"); 048 // Lookup the isNull method 049 this.isNull = restrictions.getMethod("isNull", new Class[]{String.class}); 050 } catch (ClassNotFoundException e) { 051 throw new RuntimeException(e); 052 } catch (NoSuchMethodException e) { 053 throw new RuntimeException(e); 054 } 055 } 056 057 public Object asCriterion() { 058 try { 059 // All feature have parents, so checking for null means none will ever be returned. 060 return this.isNull.invoke(null,new Object[]{"parent"}); 061 } catch (InvocationTargetException e) { 062 throw new RuntimeException(e); 063 } catch (IllegalAccessException e) { 064 throw new RuntimeException(e); 065 } 066 } 067 068 public Map criterionAliasMap() { 069 return Collections.EMPTY_MAP; 070 } 071 072 public boolean equals(Object o) { 073 return o instanceof BioSQLAcceptNoneFilter; 074 } 075 076 public boolean accept(Feature f) { return false; } 077 078 public int hashCode() { 079 return 1; 080 } 081 082 public String toString() { 083 return "None"; 084 } 085} 086