Add guava cache for Strings to OBOFormatParser. Cache is restricted t…

…o 8K chars.

Cached values are looked up in getParseUntil(String,boolean)

Call freeze on header frame, term frames, and typedef frames.

oboformat/src/main/java/org/obolibrary/oboformat/parser/OBOFormatParser.java

@@ -1,5 +1,8 @@
 package org.obolibrary.oboformat.parser;
 
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.Weigher;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
@@ -13,12 +16,15 @@
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-
-import org.obolibrary.oboformat.model.*;
+import org.obolibrary.oboformat.model.Clause;
+import org.obolibrary.oboformat.model.Frame;
 import org.obolibrary.oboformat.model.Frame.FrameType;
+import org.obolibrary.oboformat.model.FrameMergeException;
+import org.obolibrary.oboformat.model.OBODoc;
+import org.obolibrary.oboformat.model.QualifierValue;
+import org.obolibrary.oboformat.model.Xref;
 import org.obolibrary.oboformat.parser.OBOFormatConstants.OboFormatTag;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -37,6 +43,40 @@ protected static SimpleDateFormat getISODateFormat() {
     private boolean followImport;
     private Object location;
     protected final MyStream stream;
+    public  final com.google.common.cache.LoadingCache<String,String> stringCache;
+
+    /**
+     *
+     */
+    public OBOFormatParser() {
+        this(new MyStream());
+    }
+
+    /**
+     *
+     * @param s
+     */
+    protected OBOFormatParser(MyStream s) {
+        stream = s;
+        Weigher<String, String> stringWeigher = new Weigher<String, String>() {
+            @Override
+            public int weigh(String key, String value) {
+                return key.length();
+            }
+        };
+        CacheLoader<String, String> loader = new CacheLoader<String, String>() {
+            @Override
+            public String load(String key) throws Exception {
+                return key;
+            }
+        };
+        if (LOG.isDebugEnabled()) {
+            stringCache = CacheBuilder.newBuilder().recordStats().maximumWeight(8192*1024).weigher(stringWeigher).build(loader);
+        } else {
+            stringCache = CacheBuilder.newBuilder().maximumWeight(8192*1024).weigher(stringWeigher).build(loader);
+        }
+    }
+
 
     protected static class MyStream {
 
@@ -158,17 +198,6 @@ public int getLineNo() {
         }
     }
 
-    /**
-     * 
-     */
-    public OBOFormatParser() {
-        this(new MyStream());
-    }
-
-    protected OBOFormatParser(MyStream s) {
-        stream = s;
-    }
-
     /**
      * @param r
      *        r
@@ -347,6 +376,7 @@ public void parseOBODoc(@Nonnull OBODoc obodoc) {
         Frame h = new Frame(FrameType.HEADER);
         obodoc.setHeaderFrame(h);
         parseHeaderFrame(h);
+        h.freeze();
         parseZeroOrMoreWsOptCmtNl();
         while (!stream.eof()) {
             parseEntityFrame(obodoc);
@@ -573,6 +603,7 @@ public void parseTermFrame(@Nonnull OBODoc obodoc) {
                 parseZeroOrMoreWsOptCmtNl();
             }
             try {
+                f.freeze();
                 obodoc.addFrame(f);
             } catch (FrameMergeException e) {
                 throw new OBOFormatParserException("Could not add frame " + f
@@ -710,6 +741,7 @@ public void parseTypedefFrame(@Nonnull OBODoc obodoc) {
                 parseZeroOrMoreWsOptCmtNl();
             }
             try {
+                f.freeze();
                 obodoc.addFrame(f);
             } catch (FrameMergeException e) {
                 throw new OBOFormatParserException("Could not add frame " + f
@@ -1435,7 +1467,13 @@ private String getParseUntil(@Nonnull String compl, boolean commaWhitespace) {
             ret = sb.toString();
         }
         stream.advance(i);
-        return ret;
+        String cachedValue = stringCache.getUnchecked(ret);
+        if(LOG.isTraceEnabled()) {
+            if (ret != cachedValue) {
+                LOG.trace("Cache hit for  {}", cachedValue);
+            }
+        }
+        return cachedValue;
     }
 
     @Nonnull