Issue 21 serialize back to x12

build.gradle

@@ -30,6 +30,7 @@ dependencies {
     api 'com.thoughtworks.xstream:xstream:1.4.11.1'
 
     testImplementation 'junit:junit:4.13'
+    testImplementation 'commons-io:commons-io:2.6'
 }
 
 jar {

src/main/java/com/imsweb/x12/LineBreak.java

@@ -0,0 +1,30 @@
+package com.imsweb.x12;
+
+/**
+ * Choice of line break when serializing x12 documents.
+ */
+public enum LineBreak {
+
+  /**
+   * Unix line endings.
+   */
+  LF("\n"),
+  /**
+   * Windows line endings.
+   */
+  CRLF("\r\n"),
+  /**
+   * No line breaks at all.
+   */
+  NONE("");
+
+  private String _lineBreakString;
+
+  LineBreak(String lineBreakString) {
+    this._lineBreakString = lineBreakString;
+  }
+
+  public String getLineBreakString() {
+    return _lineBreakString;
+  }
+}

src/main/java/com/imsweb/x12/Loop.java

@@ -6,8 +6,14 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
+import com.imsweb.x12.converters.ElementConverter;
+import com.imsweb.x12.mapping.LoopDefinition;
+import com.imsweb.x12.mapping.Positioned;
+import com.imsweb.x12.mapping.SegmentDefinition;
 import com.thoughtworks.xstream.XStream;
 import com.thoughtworks.xstream.annotations.XStreamAlias;
 import com.thoughtworks.xstream.annotations.XStreamOmitField;
@@ -19,8 +25,6 @@
 import com.thoughtworks.xstream.security.NoTypePermission;
 import com.thoughtworks.xstream.security.WildcardTypePermission;
 
-import com.imsweb.x12.converters.ElementConverter;
-
 /**
  * The Loop class is the representation of an Loop in a ANSI X12 transaction. The building block of an X12 transaction is an element. Some
  * elements may be made of sub elements. Elements combine to form segments.  Segments are grouped as loops. And a set of loops form an X12
@@ -567,7 +571,9 @@ public Loop findTopParentById(String parentId) {
     }
 
     /**
-     * Returns the Loop in X12 String format. This method is used to convert the X12 object into a X12 transaction.
+     * Returns an X12 String for this loop, but it will not be
+     * properly ordered. For properly ordered X12 string use toX12String.
+     *
      * @return String representation
      */
     @Override
@@ -584,6 +590,71 @@ public String toString() {
         return dump.toString();
     }
 
+    /**
+     * Returns the Loop in X12 String format. This method is used to convert the X12 object into a X12 transaction.
+     * 
+     * This will first go through each segment and will return the properly separated string for the segment.
+     * 
+     * After the segments are seriaized to X12 strings, it will then go through the Loops (in the correct order) and
+     * recursively call this function for the child loops.
+     * 
+     * @param loopDefinition The definition of the loop that we are currently on.
+     * @return String representation The segments from this loop, including child loops.
+     */
+    public String toX12String(LoopDefinition loopDefinition) {
+        StringBuilder dump = new StringBuilder();
+
+        Set<Positioned> segmentsAndLoops = new TreeSet<>();
+        if (loopDefinition.getLoop() != null) {
+            segmentsAndLoops.addAll(loopDefinition.getLoop());
+        }
+        if (loopDefinition.getSegment() != null) {
+            segmentsAndLoops.addAll(loopDefinition.getSegment());
+        }
+        for (Positioned positioned : segmentsAndLoops) {
+            if (positioned instanceof SegmentDefinition) {
+                SegmentDefinition segmentDefinition = (SegmentDefinition)positioned;
+                int idx = 0;
+                Segment segment;
+                while ((segment = getSegment(segmentDefinition.getXid(), idx++)) != null) {
+                    dump.append(segment);
+                    dump.append(_separators.getSegment());
+                    dump.append(_separators.getLineBreak().getLineBreakString());
+                }
+            }
+            else if (positioned instanceof LoopDefinition) {
+                LoopDefinition innerLoopDefinition = (LoopDefinition)positioned;
+                int idx = 0;
+                Loop innerLoop;
+                while ((innerLoop = getLoopForPrinting(innerLoopDefinition, idx++)) != null) {
+                    dump.append(innerLoop.toX12String(innerLoopDefinition));
+                }
+            }
+        }
+        return dump.toString();
+    }
+
+    /**
+     * Send a LoopDefinition and the index of an loop, fetch the loop from the 
+     * child loops that matches, given that the parentLoop has this loop as a child.
+     * @param loopDefinition Loop definition for this spot in the x12 document.
+     * @param idx The index of the loops returned thus far.
+     * @return The child loop from the loops, or null otherwise.
+     */
+    private Loop getLoopForPrinting(LoopDefinition loopDefinition, int idx) {
+        Loop loop = getLoop(loopDefinition.getXid(), idx);
+
+        // We need to check that the loop we have gotten from getLoop
+        // is actually a direct child of the current loop we are processing from the
+        // loop definition.
+
+        if (loop != null && _loops.stream().noneMatch(parentLoop -> parentLoop.getId().equals(loop.getId()))) {
+            return null;
+        }
+
+        return loop;
+    }
+
     /**
      * Returns the Loop in XML String format.
      * @return XML String

src/main/java/com/imsweb/x12/Separators.java

@@ -14,6 +14,7 @@ public class Separators {
     private Pattern _segmentPattern;
     private Pattern _elementPattern;
     private Pattern _compositePattern;
+    private LineBreak _lineBreak;
 
     /**
      * Default constructor.
@@ -22,6 +23,7 @@ public Separators() {
         setSegment('~');
         setElement('*');
         setCompositeElement(':');
+        setLineBreak(LineBreak.NONE);
     }
 
     /**
@@ -107,6 +109,14 @@ public String[] splitComposite(String line) {
         return (line != null && _compositePattern != null) ? _compositePattern.split(line) : null;
     }
 
+    public LineBreak getLineBreak() {
+        return _lineBreak;
+    }
+
+    public void setLineBreak(LineBreak lineBreak) {
+        this._lineBreak = lineBreak;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

src/main/java/com/imsweb/x12/mapping/LoopDefinition.java

@@ -4,16 +4,16 @@
 package com.imsweb.x12.mapping;
 
 import java.util.List;
+import java.util.Objects;
 
+import com.imsweb.x12.mapping.TransactionDefinition.Usage;
 import com.thoughtworks.xstream.annotations.XStreamAlias;
 import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
 import com.thoughtworks.xstream.annotations.XStreamConverter;
 import com.thoughtworks.xstream.annotations.XStreamImplicit;
 
-import com.imsweb.x12.mapping.TransactionDefinition.Usage;
-
 @XStreamAlias("loop")
-public class LoopDefinition {
+public class LoopDefinition implements Positioned {
 
     @XStreamAlias("xid")
     @XStreamAsAttribute
@@ -37,6 +37,7 @@ public class LoopDefinition {
     @XStreamImplicit
     private List<LoopDefinition> _loop;
 
+    @Override
     public String getXid() {
         return _xid;
     }
@@ -49,6 +50,7 @@ public Usage getUsage() {
         return _usage;
     }
 
+    @Override
     public String getPos() {
         return _pos;
     }
@@ -69,4 +71,23 @@ public List<LoopDefinition> getLoop() {
         return _loop;
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        LoopDefinition that = (LoopDefinition) o;
+        return Objects.equals(_xid, that._xid) &&
+            Objects.equals(_type, that._type) &&
+            _usage == that._usage &&
+            Objects.equals(_pos, that._pos) &&
+            Objects.equals(_repeat, that._repeat) &&
+            Objects.equals(_name, that._name) &&
+            Objects.equals(_segment, that._segment) &&
+            Objects.equals(_loop, that._loop);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(_xid, _type, _usage, _pos, _repeat, _name, _segment, _loop);
+    }
 }

src/main/java/com/imsweb/x12/mapping/Positioned.java

@@ -0,0 +1,17 @@
+package com.imsweb.x12.mapping;
+
+import java.util.Objects;
+
+public interface Positioned extends Comparable<Positioned> {
+  String getXid();
+  String getPos();
+
+  @Override
+  default int compareTo(Positioned o) {
+    Objects.requireNonNull(o);
+    if (getPos().equals(o.getPos())) {
+      return getXid().compareTo(o.getXid());
+    }
+    return getPos().compareTo(o.getPos());
+  }
+}

src/main/java/com/imsweb/x12/mapping/SegmentDefinition.java

@@ -4,16 +4,16 @@
 package com.imsweb.x12.mapping;
 
 import java.util.List;
+import java.util.Objects;
 
+import com.imsweb.x12.mapping.TransactionDefinition.Usage;
 import com.thoughtworks.xstream.annotations.XStreamAlias;
 import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
 import com.thoughtworks.xstream.annotations.XStreamConverter;
 import com.thoughtworks.xstream.annotations.XStreamImplicit;
 
-import com.imsweb.x12.mapping.TransactionDefinition.Usage;
-
 @XStreamAlias("segment")
-public class SegmentDefinition {
+public class SegmentDefinition implements Positioned {
 
     @XStreamAlias("xid")
     @XStreamAsAttribute
@@ -37,6 +37,7 @@ public class SegmentDefinition {
     @XStreamImplicit
     private List<CompositeDefinition> _composites;
 
+    @Override
     public String getXid() {
         return _xid;
     }
@@ -49,6 +50,7 @@ public Usage getUsage() {
         return _usage;
     }
 
+    @Override
     public String getPos() {
         return _pos;
     }
@@ -69,4 +71,23 @@ public List<CompositeDefinition> getComposites() {
         return _composites;
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SegmentDefinition that = (SegmentDefinition) o;
+        return Objects.equals(_xid, that._xid) &&
+            Objects.equals(_name, that._name) &&
+            _usage == that._usage &&
+            Objects.equals(_pos, that._pos) &&
+            Objects.equals(_maxUse, that._maxUse) &&
+            Objects.equals(_syntax, that._syntax) &&
+            Objects.equals(_elements, that._elements) &&
+            Objects.equals(_composites, that._composites);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(_xid, _name, _usage, _pos, _maxUse, _syntax, _elements, _composites);
+    }
 }