Extracted group order arrays into constants, reducing object allocations

Author: amichair

quickfixj-codegenerator/src/main/resources/org/quickfixj/codegenerator/Message.xsl

@@ -115,10 +115,10 @@ public class Message extends quickfix.Message {
 	public static class <xsl:value-of select="@name"/> extends Group {
 
 		static final long serialVersionUID = <xsl:value-of select="$serialVersionUID"/>;
+		private static final int[] ORDER = {<xsl:apply-templates select="field|component|group" mode="group-field-numbers"/>0};
 
 		public <xsl:value-of select="@name"/>() {
-			super(<xsl:value-of select="/fix/fields/field[@name=$groupFieldName]/@number"/>, <xsl:apply-templates select="field|component|group" mode="group-delimeter"/>,
-				new int[] {<xsl:apply-templates select="field|component|group" mode="group-field-numbers"/>0});
+			super(<xsl:value-of select="/fix/fields/field[@name=$groupFieldName]/@number"/>, <xsl:apply-templates select="field|component|group" mode="group-delimeter"/>, ORDER);
 		}
 		<xsl:apply-templates select="field|component|group" mode="field-accessors"/>
 	}

quickfixj-codegenerator/src/main/resources/org/quickfixj/codegenerator/MessageSubclass.xsl

@@ -172,10 +172,10 @@ import quickfix.Group;</xsl:if>
 	public static class <xsl:value-of select="@name"/> extends Group {
 
 		static final long serialVersionUID = <xsl:value-of select="$serialVersionUID"/>;
+		private static final int[] ORDER = {<xsl:apply-templates select="field|component|group" mode="group-field-numbers"/>0};
 
 		public <xsl:value-of select="@name"/>() {
-			super(<xsl:value-of select="/fix/fields/field[@name=$groupFieldName]/@number"/>, <xsl:apply-templates select="field|component|group" mode="group-delimeter"/>,
-				new int[] {<xsl:apply-templates select="field|component|group" mode="group-field-numbers"/> 0 });
+			super(<xsl:value-of select="/fix/fields/field[@name=$groupFieldName]/@number"/>, <xsl:apply-templates select="field|component|group" mode="group-delimeter"/>, ORDER);
 		}
 		<xsl:apply-templates select="field|component|group" mode="field-accessors"/>
 	}

quickfixj-core/src/main/java/quickfix/FieldMap.java

@@ -56,6 +56,12 @@ public abstract class FieldMap implements Serializable {
 
     private final TreeMap<Integer, List<Group>> groups = new TreeMap<Integer, List<Group>>();
 
+    /**
+     * Constructs a FieldMap with the given field order.
+     * The given array must not be modified.
+     *
+     * @param fieldOrder the field order, or null if there is none
+     */
     protected FieldMap(int[] fieldOrder) {
         this.fieldOrder = fieldOrder;
         fields = new TreeMap<Integer, Field<?>>(
@@ -66,6 +72,12 @@ protected FieldMap() {
         this(null);
     }
 
+    /**
+     * Returns the order of fields in the group.
+     * The returned array must not be modified.
+     *
+     * @return the field order
+     */
     public int[] getFieldOrder() {
         return fieldOrder;
     }