Refactor of query plan hash - add HashQueryPlan, HashQuery etc

src/main/java/com/avaje/ebeaninternal/api/HashQueryPlan.java

@@ -0,0 +1,46 @@
+package com.avaje.ebeaninternal.api;
+
+import java.util.Objects;
+
+/**
+ * A hash for a query plan.
+ */
+public class HashQueryPlan {
+
+  private final String rawSql;
+  
+  private final int planHash;
+  
+  private final int bindCount;
+
+  public HashQueryPlan(String rawSql, int planHash, int bindCount) {
+    this.rawSql = rawSql;
+    this.planHash = planHash;
+    this.bindCount = bindCount;
+  }
+
+  public String toString() {
+    return planHash+":"+bindCount+(rawSql != null ? ":r" : "");
+  }
+  
+  public int hashCode() {
+    int hc = planHash;
+    hc = hc * 31 + bindCount;
+    hc = hc * 31 + Objects.hashCode(rawSql);
+    return hc;
+  }
+  
+  public boolean equals(Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (!(obj instanceof HashQueryPlan)) {
+      return false;
+    }
+    
+    HashQueryPlan e = (HashQueryPlan) obj;
+    return e.planHash == planHash 
+        && e.bindCount == bindCount
+        && Objects.equals(e.rawSql, rawSql);
+  }
+}