Improve CRS Caching, add CoordinateReferenceSystem.equals overload

pom.xml

@@ -45,6 +45,11 @@
     </properties>
 
     <dependencies>
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+            <version>2.6.2</version>
+        </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
@@ -60,8 +65,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.6.0</version>
                 <configuration>
-                    <source>1.7</source>
-                    <target>1.7</target>
+                    <source>1.8</source>
+                    <target>1.8</target>
                     <debug>true</debug>
                     <encoding>UTF-8</encoding>
                 </configuration>

src/main/java/org/locationtech/proj4j/CRSFactory.java

@@ -18,6 +18,8 @@
 import org.locationtech.proj4j.io.Proj4FileReader;
 import org.locationtech.proj4j.parser.Proj4Parser;
 
+import java.io.IOException;
+
 /**
  * A factory which can create {@link CoordinateReferenceSystem}s
  * from a variety of ways
@@ -39,7 +41,6 @@ public class CRSFactory {
 
     // TODO: add method to allow reading from arbitrary PROJ4 CS file
 
-
     /**
      * Gets the {@link Registry} used by this factory.
      *
@@ -126,9 +127,39 @@ public CoordinateReferenceSystem createFromParameters(String name, String[] para
         return parser.parse(name, params);
     }
 
+    /**
+     * Finds a EPSG Code
+     * from a PROJ.4 projection parameter string.
+     * <p>
+     * An example of a valid PROJ.4 projection parameter string is:
+     * <pre>
+     * +proj=aea +lat_1=50 +lat_2=58.5 +lat_0=45 +lon_0=-126 +x_0=1000000 +y_0=0 +ellps=GRS80 +units=m
+     * </pre>
+     *
+     * @param paramStr a PROJ.4 projection parameter string
+     * @return the specified {@link CoordinateReferenceSystem}
+     * @throws IOException if there was an issue in reading EPSG file
+     */
+    public String readEpsgFromParameters(String paramStr) throws IOException {
+        return readEpsgFromParameters(splitParameters(paramStr));
+    }
+
+    /**
+     * Finds a EPSG Code
+     * defined by an array of PROJ.4 projection parameters.
+     * PROJ.4 parameters are generally of the form
+     * "<tt>+name=value</tt>".
+     *
+     * @param params an array of PROJ.4 projection parameters
+     * @return s String EPSG code
+     * @throws IOException if there was an issue in reading EPSG file
+     */
+    public String readEpsgFromParameters(String[] params) throws IOException {
+        return csReader.readEpsgCodeFromFile(params);
+    }
+
     private static String[] splitParameters(String paramStr) {
         String[] params = paramStr.split("\\s+");
         return params;
     }
-
 }

src/main/java/org/locationtech/proj4j/CoordinateReferenceSystem.java

@@ -22,6 +22,8 @@
 import org.locationtech.proj4j.units.Unit;
 import org.locationtech.proj4j.units.Units;
 
+import java.util.Arrays;
+
 /**
  * Represents a projected or geodetic geospatial coordinate system,
  * to which coordinates may be referenced.
@@ -119,4 +121,16 @@ public CoordinateReferenceSystem createGeographic() {
     public String toString() {
         return name;
     }
+
+    @Override
+    public boolean equals(Object that) {
+        if (this == that) {
+            return true;
+        }
+        if (that instanceof CoordinateReferenceSystem) {
+            CoordinateReferenceSystem cr = (CoordinateReferenceSystem) that;
+            return name.equals(cr.name) && datum.isEqual(cr.getDatum()) && Arrays.equals(params, cr.params);
+        }
+        return false;
+    }
 }

src/main/java/org/locationtech/proj4j/io/Proj4FileReader.java

@@ -21,6 +21,7 @@
 import java.io.InputStreamReader;
 import java.io.StreamTokenizer;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class Proj4FileReader {
@@ -156,4 +157,60 @@ public String[] getParameters(String crsName) {
         return null;
     }
 
+    public String readEpsgCodeFromFile(String[] params) throws IOException {
+        InputStream inStr = Proj4FileReader.class.getClassLoader().getResourceAsStream("proj4/nad/epsg");
+
+        if (inStr == null) {
+            throw new IllegalStateException("Unable to access CRS file: EPSG");
+        }
+        BufferedReader reader = new BufferedReader(new InputStreamReader(inStr));
+
+        StreamTokenizer t = createTokenizer(reader);
+
+        t.nextToken();
+        while (t.ttype == '<') {
+            t.nextToken();
+            if (t.ttype != StreamTokenizer.TT_WORD)
+                throw new IOException(t.lineno() + ": Word expected after '<'");
+            String crsName = t.sval;
+            t.nextToken();
+            if (t.ttype != '>')
+                throw new IOException(t.lineno() + ": '>' expected");
+            t.nextToken();
+            List v = new ArrayList();
+
+            while (t.ttype != '<') {
+                if (t.ttype == '+')
+                    t.nextToken();
+                if (t.ttype != StreamTokenizer.TT_WORD)
+                    throw new IOException(t.lineno() + ": Word expected after '+'");
+                String key = t.sval;
+                t.nextToken();
+
+
+                // parse =arg, if any
+                if (t.ttype == '=') {
+                    t.nextToken();
+                    //Removed check to allow for proj4 hack +nadgrids=@null
+                    //if ( t.ttype != StreamTokenizer.TT_WORD )
+                    //  throw new IOException( t.lineno()+": Value expected after '='" );
+                    String value = t.sval;
+                    t.nextToken();
+                    addParam(v, key, value);
+                } else {
+                    // add param with no value
+                    addParam(v, key, null);
+                }
+            }
+            t.nextToken();
+            if (t.ttype != '>')
+                throw new IOException(t.lineno() + ": '<>' expected");
+            t.nextToken();
+
+            String[] paramsParsed = (String[]) v.toArray(new String[0]);
+
+            if(Arrays.equals(params, paramsParsed)) return crsName;
+        }
+        return null;
+    }
 }

src/main/java/org/locationtech/proj4j/util/CRSCache.java

@@ -15,31 +15,51 @@
  */
 package org.locationtech.proj4j.util;
 
-import java.util.HashMap;
-import java.util.Map;
-
 import org.locationtech.proj4j.*;
 
-public class CRSCache {
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
 
-    private static Map<String, CoordinateReferenceSystem> projCache = new HashMap<String, CoordinateReferenceSystem>();
+import java.io.IOException;
 
+public class CRSCache {
     private static CRSFactory crsFactory = new CRSFactory();
+    private Cache<String, CoordinateReferenceSystem> crsCache = Caffeine.newBuilder().build();
+    private Cache<String, String> epsgCache = Caffeine.newBuilder().build();
 
-// TODO: provide limit on number of items in cache (LRU)
+    public CRSCache CRSCache() {
+        crsCache = Caffeine.newBuilder().build();
+        return this;
+    }
 
-    public CRSCache() {
-        super();
+    public CRSCache CRSCache(Cache<String, CoordinateReferenceSystem> crsCache, Cache<String, String> epsgCache) {
+        this.crsCache = crsCache;
+        this.epsgCache = epsgCache;
+        return this;
     }
 
     public CoordinateReferenceSystem createFromName(String name)
             throws UnsupportedParameterException, InvalidValueException, UnknownAuthorityCodeException {
-        CoordinateReferenceSystem proj = (CoordinateReferenceSystem) projCache.get(name);
-        if (proj == null) {
-            proj = crsFactory.createFromName(name);
-            projCache.put(name, proj);
-        }
-        return proj;
+        return crsCache.get(name, k -> crsFactory.createFromName(name));
+    }
+
+    public CoordinateReferenceSystem createFromParameters(String name, String paramStr)
+            throws UnsupportedParameterException, InvalidValueException {
+        String nonNullName = name == null ? "" : name;
+        return crsCache.get(nonNullName + paramStr, k -> crsFactory.createFromParameters(name, paramStr));
     }
 
+    public CoordinateReferenceSystem createFromParameters(String name, String[] params)
+            throws UnsupportedParameterException, InvalidValueException {
+        String nonNullName = name == null ? "" : name;
+        return crsCache.get(nonNullName + String.join(" ", params), k -> crsFactory.createFromParameters(name, params));
+    }
+
+    public String readEpsgFromParameters(String paramStr) {
+        return epsgCache.get(paramStr, k -> { try { return crsFactory.readEpsgFromParameters(paramStr); } catch (IOException e) {  return null; } });
+    }
+
+    public String readEpsgFromParameters(String[] params) {
+        return epsgCache.get(String.join(" ", params), k -> { try { return crsFactory.readEpsgFromParameters(params); } catch (IOException e) {  return null; } });
+    }
 }