Improve CRS Caching, add CoordinateReferenceSystem.equals overload (#33)

* Improve CRS Caching, add CoordinateReferenceSystem.equals overload

Signed-off-by: Grigory Pomadchin <gr.pomadchin@gmail.com>

pom.xml

@@ -60,8 +60,8 @@
                 <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

@@ -15,12 +15,15 @@
  */
 package org.locationtech.proj4j.io;
 
+import org.locationtech.proj4j.util.Pair;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.StreamTokenizer;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class Proj4FileReader {
@@ -71,49 +74,14 @@ private StreamTokenizer createTokenizer(BufferedReader reader) {
         return t;
     }
 
-    private String[] readFile(BufferedReader reader, String name)
-            throws IOException {
+    private String[] readFile(BufferedReader reader, String name) throws IOException {
         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();
+            Pair<String, List> pair = parseTokenizer(t);
+            String crsName = pair.fst();
+            List v = pair.snd();
 
             // found requested CRS?
             if (crsName.equals(name)) {
@@ -156,4 +124,68 @@ 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 == '<') {
+            Pair<String, List> pair = parseTokenizer(t);
+            String crsName = pair.fst();
+            List v = pair.snd();
+
+            String[] paramsParsed = (String[]) v.toArray(new String[0]);
+
+            if(Arrays.equals(params, paramsParsed)) return crsName;
+        }
+        return null;
+    }
+
+    private static Pair<String, List> parseTokenizer(StreamTokenizer t) throws IOException {
+        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();
+
+        return Pair.create(crsName, v);
+    }
 }

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

@@ -15,31 +15,64 @@
  */
 package org.locationtech.proj4j.util;
 
-import java.util.HashMap;
-import java.util.Map;
-
 import org.locationtech.proj4j.*;
 
-public class CRSCache {
-
-    private static Map<String, CoordinateReferenceSystem> projCache = new HashMap<String, CoordinateReferenceSystem>();
+import java.io.IOException;
+import java.util.concurrent.ConcurrentHashMap;
 
+public class CRSCache {
     private static CRSFactory crsFactory = new CRSFactory();
 
-// TODO: provide limit on number of items in cache (LRU)
+    private ConcurrentHashMap<String, CoordinateReferenceSystem> crsCache = new ConcurrentHashMap<>();
+    private ConcurrentHashMap<String, String> epsgCache = new ConcurrentHashMap<>();
 
-    public CRSCache() {
-        super();
+    public CRSCache CRSCache() {
+        crsCache = new ConcurrentHashMap<>();
+        epsgCache = new ConcurrentHashMap<>();
+        return this;
+    }
+
+    public CRSCache CRSCache(ConcurrentHashMap<String, CoordinateReferenceSystem> crsCache, ConcurrentHashMap<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;
+        CoordinateReferenceSystem res = crsCache.get(name);
+        if(res != null) return res;
+        return crsCache.computeIfAbsent(name, k -> crsFactory.createFromName(name));
     }
 
+    public CoordinateReferenceSystem createFromParameters(String name, String paramStr)
+            throws UnsupportedParameterException, InvalidValueException {
+        String nonNullName = name == null ? "" : name;
+        String key = nonNullName + paramStr;
+        CoordinateReferenceSystem res = crsCache.get(key);
+        if(res != null) return res;
+        return crsCache.computeIfAbsent(key, k -> crsFactory.createFromParameters(name, paramStr));
+    }
+
+    public CoordinateReferenceSystem createFromParameters(String name, String[] params)
+            throws UnsupportedParameterException, InvalidValueException {
+        String nonNullName = name == null ? "" : name;
+        String key = nonNullName + String.join(" ", params);
+        CoordinateReferenceSystem res = crsCache.get(key);
+        if(res != null) return res;
+        return crsCache.computeIfAbsent(key, k -> crsFactory.createFromParameters(name, params));
+    }
+
+    public String readEpsgFromParameters(String paramStr) {
+        String res = epsgCache.get(paramStr);
+        if(res != null) return res;
+        return epsgCache.computeIfAbsent(paramStr, k -> { try { return crsFactory.readEpsgFromParameters(paramStr); } catch (IOException e) {  return null; } });
+    }
+
+    public String readEpsgFromParameters(String[] params) {
+        String paramStr = String.join(" ", params);
+        String res = epsgCache.get(paramStr);
+        if(res != null) return res;
+        return epsgCache.computeIfAbsent(paramStr, k -> { try { return crsFactory.readEpsgFromParameters(params); } catch (IOException e) {  return null; } });
+    }
 }

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

@@ -0,0 +1,78 @@
+/*******************************************************************************
+ * Copyright 2009, 2017 Martin Davis
+ *
+ * Licensed 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.locationtech.proj4j.util;
+
+public class Pair<A, B> {
+
+    private A first;
+    private B second;
+
+    public Pair() {
+        super();
+    }
+
+    public Pair(A first, B second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    public A fst() {
+        return first;
+    }
+
+    public void setFirst(A first) {
+        this.first = first;
+    }
+
+    public B snd() {
+        return second;
+    }
+
+    public void setSecond(B second) {
+        this.second = second;
+    }
+
+    @Override
+    public String toString() {
+        return "<" + first + "," + second + ">";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        final Pair<?, ?> other = (Pair<?, ?>) obj;
+        if (first == null) {
+            if (other.first != null)
+                return false;
+        } else if (!first.equals(other.first))
+            return false;
+        if (second == null) {
+            if (other.second != null)
+                return false;
+        } else if (!second.equals(other.second))
+            return false;
+        return true;
+    }
+
+    public static <A, B> Pair<A, B> create(A first, B second) {
+        return new Pair<A, B>(first, second);
+    }
+}