From 8c16310474c2e769de68b57df4f3ae872e454089 Mon Sep 17 00:00:00 2001
From: Thomas Butz <tbutz@optitool.de>
Date: Thu, 11 Apr 2024 10:20:52 +0200
Subject: [PATCH] Avoid String concatenation in loops

---
 .../routing/RoutingAlgorithmWithOSMTest.java  |  2 +-
 .../main/java/com/graphhopper/GHResponse.java | 24 +++++++++----------
 .../java/com/graphhopper/ResponsePath.java    |  8 +++----
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/core/src/test/java/com/graphhopper/routing/RoutingAlgorithmWithOSMTest.java b/core/src/test/java/com/graphhopper/routing/RoutingAlgorithmWithOSMTest.java
index 5e62a603eed..0cbce97c208 100644
--- a/core/src/test/java/com/graphhopper/routing/RoutingAlgorithmWithOSMTest.java
+++ b/core/src/test/java/com/graphhopper/routing/RoutingAlgorithmWithOSMTest.java
@@ -733,7 +733,7 @@ private void checkQueries(GraphHopper hopper, List<Query> queries) {
                 // for edge-based routing we expect a slightly different algo name for CH
                 if (profile.hasTurnCosts())
                     expectedAlgo = expectedAlgo.replaceAll("\\|ch-routing", "|ch|edge_based|no_sod-routing");
-                assertTrue(res.getBest().getDebugInfo().contains(expectedAlgo),
+                assertTrue(res.getBest().getDebugInfo().toString().contains(expectedAlgo),
                         "Response does not contain expected algo string. Expected: '" + expectedAlgo +
                                 "', got: '" + res.getBest().getDebugInfo() + "'");
             }
diff --git a/web-api/src/main/java/com/graphhopper/GHResponse.java b/web-api/src/main/java/com/graphhopper/GHResponse.java
index ffd99461226..2ec22ef3c9f 100644
--- a/web-api/src/main/java/com/graphhopper/GHResponse.java
+++ b/web-api/src/main/java/com/graphhopper/GHResponse.java
@@ -32,7 +32,7 @@ public class GHResponse {
     private final List<Throwable> errors = new ArrayList<>(4);
     private PMap hintsMap = new PMap();
     private final List<ResponsePath> responsePaths = new ArrayList<>(5);
-    private String debugInfo = "";
+    private final StringBuilder debugInfo = new StringBuilder();
 
     public GHResponse() {
     }
@@ -70,20 +70,20 @@ public void addDebugInfo(String debugInfo) {
             throw new IllegalStateException("Debug information has to be none null");
 
         if (!this.debugInfo.isEmpty())
-            this.debugInfo += "; ";
+            this.debugInfo.append("; ");
 
-        this.debugInfo += debugInfo;
+        this.debugInfo.append(debugInfo);
     }
 
     public String getDebugInfo() {
-        String str = debugInfo;
+        StringBuilder str = new StringBuilder(debugInfo);
         for (ResponsePath p : responsePaths) {
             if (!str.isEmpty())
-                str += "; ";
+                str.append("; ");
 
-            str += p.getDebugInfo();
+            str.append(p.getDebugInfo());
         }
-        return str;
+        return str.toString();
     }
 
     /**
@@ -126,18 +126,18 @@ public GHResponse addError(Throwable error) {
 
     @Override
     public String toString() {
-        String str = "";
+        StringBuilder str = new StringBuilder();
         for (ResponsePath a : responsePaths) {
-            str += "; " + a.toString();
+            str.append("; ").append(a.toString());
         }
 
         if (responsePaths.isEmpty())
-            str = "no paths";
+            str.append("no paths");
 
         if (!errors.isEmpty())
-            str += ", main errors: " + errors.toString();
+            str.append(", main errors: ").append(errors);
 
-        return str;
+        return str.toString();
     }
 
     public void setHints(PMap hints) {
diff --git a/web-api/src/main/java/com/graphhopper/ResponsePath.java b/web-api/src/main/java/com/graphhopper/ResponsePath.java
index 8638efc73c7..bb79e06cff3 100644
--- a/web-api/src/main/java/com/graphhopper/ResponsePath.java
+++ b/web-api/src/main/java/com/graphhopper/ResponsePath.java
@@ -39,7 +39,7 @@ public class ResponsePath {
     private double descend;
     private double routeWeight;
     private long time;
-    private String debugInfo = "";
+    private final StringBuilder debugInfo = new StringBuilder();
     private InstructionList instructions;
     private PointList waypointList = PointList.EMPTY;
     private List<Integer> waypointIndices = new ArrayList<>();
@@ -71,13 +71,13 @@ public ResponsePath addDebugInfo(String debugInfo) {
             throw new IllegalStateException("Debug information has to be none null");
 
         if (!this.debugInfo.isEmpty())
-            this.debugInfo += ";";
+            this.debugInfo.append(";");
 
-        this.debugInfo += debugInfo;
+        this.debugInfo.append(debugInfo);
         return this;
     }
 
-    public String getDebugInfo() {
+    public StringBuilder getDebugInfo() {
         return debugInfo;
     }