4 files changed, 161 insertions, 0 deletions

diff --git a/src/uk/ac/ox/cs/pagoda/model/AnswerTerm.java b/src/uk/ac/ox/cs/pagoda/model/AnswerTerm.java
new file mode 100644
index 0000000..777a35c
--- /dev/null
+++ b/src/uk/ac/ox/cs/pagoda/model/AnswerTerm.java
@@ -0,0 +1,10 @@
+package uk.ac.ox.cs.pagoda.model;
+
+public abstract class AnswerTerm {
+
+        protected static Trie instances = new Trie(); 
+        protected static int SkolemCounter = 0; 
+        protected static int OriginalCounter = 0; 
+
+        public abstract String toString();
+}
diff --git a/src/uk/ac/ox/cs/pagoda/model/IRI.java b/src/uk/ac/ox/cs/pagoda/model/IRI.java
new file mode 100644
index 0000000..7dc5242
--- /dev/null
+++ b/src/uk/ac/ox/cs/pagoda/model/IRI.java
@@ -0,0 +1,28 @@
+package uk.ac.ox.cs.pagoda.model;
+
+import uk.ac.ox.cs.pagoda.util.Namespace;
+
+public class IRI extends AnswerTerm {
+
+        int id; 
+        String iri; 
+        
+        private IRI(String iri, int id) {
+                this.iri = iri; 
+                this.id = id; 
+        }
+        
+        public IRI create(String iri) {
+                IRI instance = (IRI) instances.find(iri); 
+                if (instance != null) return instance;
+                instance = new IRI(iri, iri.startsWith(Namespace.PAGODA_ANONY) ? --SkolemCounter : ++OriginalCounter);
+                instances.insert(iri, instance);
+                return instance; 
+        }
+
+        @Override
+        public String toString() {
+                return "<" + iri + ">";
+        }
+        
+}
diff --git a/src/uk/ac/ox/cs/pagoda/model/Literal.java b/src/uk/ac/ox/cs/pagoda/model/Literal.java
new file mode 100644
index 0000000..0a4dff2
--- /dev/null
+++ b/src/uk/ac/ox/cs/pagoda/model/Literal.java
@@ -0,0 +1,28 @@
+package uk.ac.ox.cs.pagoda.model;
+
+public class Literal extends AnswerTerm {
+
+        int id; 
+        String lexicalForm, datatype; 
+        
+        public Literal(String lexicalForm2, String datatype2, int i) {
+                this.lexicalForm = lexicalForm2; 
+                this.datatype = datatype2; 
+                this.id = i; 
+        }
+
+        public static Literal create(String lexicalForm, String datatype) {
+                String key = lexicalForm + "^^" + datatype; 
+                Literal instance = (Literal) instances.find(key);
+                if (instance != null) return instance;
+                instance = new Literal(lexicalForm, datatype, ++OriginalCounter); 
+                instances.insert(key, instance);
+                return instance;
+        }
+
+        @Override
+        public String toString() {
+                return "\"" + lexicalForm + "\"^^" + datatype; 
+        }
+        
+}
diff --git a/src/uk/ac/ox/cs/pagoda/model/Trie.java b/src/uk/ac/ox/cs/pagoda/model/Trie.java
new file mode 100644
index 0000000..eb9e71b
--- /dev/null
+++ b/src/uk/ac/ox/cs/pagoda/model/Trie.java
@@ -0,0 +1,95 @@
+package uk.ac.ox.cs.pagoda.model;
+
+public class Trie {
+        
+        private TrieNode root = new TrieNode("");
+        private Status findStatus;  
+
+        public void insert(String key, AnswerTerm term) {
+                findStatus.lastNode.insert(key, findStatus.lastIndex, term); 
+        }
+        
+        public AnswerTerm find(String key) {
+                findStatus = root.find(key, 0);
+                return findStatus.term; 
+        }
+        
+}
+
+class TrieNode {
+        
+        String relative;
+        TrieNode[] children = new TrieNode[256];
+
+        public TrieNode(String s) {
+                relative = s;
+        }
+
+        public void insert(String key, int index, AnswerTerm term) {
+                int nextChar = (int) key.charAt(index); 
+                if (children[nextChar] == null) {
+                        children[nextChar] = new TrieLeaf(key.substring(index), term);
+                }
+                else {
+                        TrieNode next = children[nextChar];
+                        int len = next.isPrefixOf(key, index); 
+                        if (len == next.relative.length())
+                                insert(key, index + len, term);
+                        else {
+                                TrieNode newNext = new TrieNode(next.relative.substring(0, len)); 
+                                next.relative = next.relative.substring(len);
+                                children[nextChar] = newNext; 
+                                newNext.children[(int) next.relative.charAt(0)] = next; 
+                                insert(key, index + len, term);
+                        }
+                }
+        }
+
+        private int isPrefixOf(String key, int index) {
+                int i = 0; 
+                for (int j = index; i < relative.length() && j < key.length(); ++i, ++j)
+                        if (relative.charAt(i) != relative.charAt(j)) 
+                                break; 
+                return i;
+        }
+
+        public Status find(String key, int index) {
+                TrieNode next = children[(int) key.charAt(index)]; 
+                if (next == null)
+                        return new Status(this, index, null);
+                
+                if (next instanceof TrieLeaf) 
+                        if (next.relative.equals(key.substring(index))) 
+                                return new Status(this, index, ((TrieLeaf) next).term); 
+                        else {
+                                return new Status(this, index, null);
+                        }
+                return find(key, index + next.relative.length());
+        }
+        
+}
+
+class TrieLeaf extends TrieNode {
+        
+        AnswerTerm term; 
+
+        public TrieLeaf(String s, AnswerTerm term) {
+                super(s);
+                this.term = term; 
+        }
+
+}
+
+class Status {
+        
+        AnswerTerm term; 
+        TrieNode lastNode; 
+        int lastIndex;
+        
+        public Status(TrieNode trieNode, int index, AnswerTerm term2) {
+                this.lastNode = trieNode; 
+                this.lastIndex = index; 
+                this.term = term2; 
+        }
+
+}
\ No newline at end of file