| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.kernel.se.dto.module; |
| 17 | |
| 18 | import org.apache.commons.lang.ArrayUtils; |
| 19 | import org.qedeq.base.utility.EqualsUtility; |
| 20 | import org.qedeq.kernel.se.base.list.Element; |
| 21 | import org.qedeq.kernel.se.base.module.Existential; |
| 22 | |
| 23 | |
| 24 | /** |
| 25 | * Usage of rule for existential generalization. |
| 26 | * |
| 27 | * @author Michael Meyling |
| 28 | */ |
| 29 | public class ExistentialVo implements Existential { |
| 30 | |
| 31 | /** Reference to previously proven formula. Usually like A -> B. */ |
| 32 | private String reference; |
| 33 | |
| 34 | /** Subject variable that we will quantify about. */ |
| 35 | private Element subjectVariable; |
| 36 | |
| 37 | /** |
| 38 | * Constructs an reason. |
| 39 | * |
| 40 | * @param reference Reference to a valid formula. |
| 41 | * @param subjectVariable Subject variable that we will quantify about. |
| 42 | */ |
| 43 | |
| 44 | public ExistentialVo(final String reference, final Element subjectVariable) { |
| 45 | this.reference = reference; |
| 46 | this.subjectVariable = subjectVariable; |
| 47 | } |
| 48 | |
| 49 | /** |
| 50 | * Default constructor. |
| 51 | */ |
| 52 | public ExistentialVo() { |
| 53 | // nothing to do |
| 54 | } |
| 55 | |
| 56 | public Existential getExistential() { |
| 57 | return this; |
| 58 | } |
| 59 | |
| 60 | public String getReference() { |
| 61 | return reference; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Set formula reference. |
| 66 | * |
| 67 | * @param reference Reference to formula. |
| 68 | */ |
| 69 | public void setReference(final String reference) { |
| 70 | this.reference = reference; |
| 71 | } |
| 72 | |
| 73 | public String[] getReferences() { |
| 74 | if (reference == null) { |
| 75 | return ArrayUtils.EMPTY_STRING_ARRAY; |
| 76 | } |
| 77 | return new String[] {reference }; |
| 78 | } |
| 79 | |
| 80 | public Element getSubjectVariable() { |
| 81 | return subjectVariable; |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * Set quantification subject variable. |
| 86 | * |
| 87 | * @param subjectVariable Set free subject variable. |
| 88 | */ |
| 89 | public void setSubjectVariable(final Element subjectVariable) { |
| 90 | this.subjectVariable = subjectVariable; |
| 91 | } |
| 92 | |
| 93 | public String getName() { |
| 94 | return "Existential"; |
| 95 | } |
| 96 | |
| 97 | public boolean equals(final Object obj) { |
| 98 | if (!(obj instanceof ExistentialVo)) { |
| 99 | return false; |
| 100 | } |
| 101 | final ExistentialVo other = (ExistentialVo) obj; |
| 102 | return EqualsUtility.equals(reference, other.reference) |
| 103 | && EqualsUtility.equals(subjectVariable, other.subjectVariable); |
| 104 | } |
| 105 | |
| 106 | public int hashCode() { |
| 107 | return (reference != null ? reference.hashCode() : 0) |
| 108 | ^ (subjectVariable != null ? 2 ^ subjectVariable.hashCode() : 0); |
| 109 | } |
| 110 | |
| 111 | public String toString() { |
| 112 | StringBuffer result = new StringBuffer(); |
| 113 | result.append(getName()); |
| 114 | if (reference != null || subjectVariable != null) { |
| 115 | result.append(" ("); |
| 116 | boolean w = false; |
| 117 | if (reference != null) { |
| 118 | result.append(reference); |
| 119 | w = true; |
| 120 | } |
| 121 | if (subjectVariable != null) { |
| 122 | if (w) { |
| 123 | result.append(", "); |
| 124 | } |
| 125 | result.append(subjectVariable); |
| 126 | w = true; |
| 127 | } |
| 128 | result.append(")"); |
| 129 | } |
| 130 | return result.toString(); |
| 131 | } |
| 132 | |
| 133 | } |