1 files changed, 84 insertions, 0 deletions
diff --git a/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java b/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java
new file mode 100644
index 0000000000..8226cc77cb
--- /dev/null
+++ b/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java
@@ -0,0 +1,84 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+package org.apache.qpid.messaging.util;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+
+/**
+ * Lexer
+ *
+ */
+
+public class Lexer
+{
+
+    private List<Token.Type> types;
+    private Token.Type eof;
+    private Pattern rexp;
+
+    public Lexer(List<Token.Type> types, Token.Type eof, Pattern rexp)
+    {
+        this.types = types;
+        this.eof = eof;
+        this.rexp = rexp;
+    }
+
+    public List<Token> lex(final String st)
+    {
+        List<Token> tokens = new ArrayList<Token>();
+
+        int position = 0;
+        Matcher m = rexp.matcher(st);
+        OUTER: while (position < st.length())
+        {
+            m.region(position, st.length());
+            if (m.lookingAt())
+            {
+                for (int i = 1; i <= m.groupCount(); i++)
+                {
+                    String value = m.group(i);
+                    if (value != null)
+                    {
+                        tokens.add(new Token(types.get(i-1), value, st, m.start(i)));
+                        position = m.end(i);
+                        continue OUTER;
+                    }
+                }
+                throw new RuntimeException("no group matched");
+            }
+            else
+            {
+                throw new LexError("unrecognized characters line:" + LineInfo.get(st, position));
+            }
+        }
+
+        tokens.add(new Token(eof, null, st, position));
+
+        return tokens;
+    }
+
+}