SOLR-5148: optimization - lazy create child doc list

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1522680 13f79535-47bb-0310-9956-ffa450edef68

solr/core/src/java/org/apache/solr/update/AddUpdateCommand.java

@@ -197,9 +197,12 @@ public class AddUpdateCommand extends UpdateCommand implements Iterable<IndexDoc
   }
 
   private void recUnwrapp(List<SolrInputDocument> unwrappedDocs, SolrInputDocument currentDoc) {
-    for (SolrInputDocument child : currentDoc.getChildDocuments()) {
+    List<SolrInputDocument> children = currentDoc.getChildDocuments();
+    if (children != null) {
+      for (SolrInputDocument child : children) {
         recUnwrapp(unwrappedDocs, child);
       }
+    }
     unwrappedDocs.add(currentDoc);
   }
 

solr/core/src/test/org/apache/solr/update/AddBlockUpdateTest.java

@@ -424,7 +424,8 @@ public class AddBlockUpdateTest extends SolrTestCaseJ4 {
     assertEquals("v2", result.getFieldValue("parent_f2"));
     
     List<SolrInputDocument> resultChilds = result.getChildDocuments();
-    assertEquals(childsNum, resultChilds.size());
+    int resultChildsSize = resultChilds == null ? 0 : resultChilds.size();
+    assertEquals(childsNum, resultChildsSize);
     
     for (int childIndex = 0; childIndex < childsNum; ++childIndex) {
       SolrInputDocument child = resultChilds.get(childIndex);
@@ -433,7 +434,9 @@ public class AddBlockUpdateTest extends SolrTestCaseJ4 {
       }
       
       List<SolrInputDocument> grandChilds = child.getChildDocuments();
-      assertEquals(childIndex * 2, grandChilds.size());
+      int grandChildsSize = grandChilds == null ? 0 : grandChilds.size();
+
+      assertEquals(childIndex * 2, grandChildsSize);
       for (int grandIndex = 0; grandIndex < childIndex * 2; ++grandIndex) {
         SolrInputDocument grandChild = grandChilds.get(grandIndex);
         assertFalse(grandChild.hasChildDocuments());

solr/solrj/src/java/org/apache/solr/client/solrj/util/ClientUtils.java

@@ -134,9 +134,11 @@ public class ClientUtils
       }
     }
 
+    if (doc.hasChildDocuments()) {
       for (SolrInputDocument childDocument : doc.getChildDocuments()) {
         writeXML(childDocument, writer);
       }
+    }
     
     writer.write("</doc>");
   }

solr/solrj/src/java/org/apache/solr/common/SolrInputDocument.java

@@ -43,12 +43,10 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
   
   public SolrInputDocument() {
     _fields = new LinkedHashMap<String,SolrInputField>();
-    _childDocuments = new ArrayList<SolrInputDocument>();
   }
   
   public SolrInputDocument(Map<String,SolrInputField> fields) {
     _fields = fields;
-    _childDocuments = new ArrayList<SolrInputDocument>();
   }
   
   /**
@@ -60,9 +58,7 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
     if( _fields != null ) {
       _fields.clear();      
     }
-    if (_childDocuments != null) {
-      _childDocuments.clear();
-    }
+    _childDocuments = null;
   }
 
   ///////////////////////////////////////////////////////////////////
@@ -198,7 +194,9 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
   @Override
   public String toString()
   {
-    return "SolrInputDocument(fields: " + _fields.values() + ", childs: " + _childDocuments + ")";
+    return "SolrInputDocument(fields: " + _fields.values()
+        + ( _childDocuments == null ? "" : (", children: " + _childDocuments) )
+        + ")";
   }
   
   public SolrInputDocument deepCopy() {
@@ -209,10 +207,12 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
     }
     clone._documentBoost = _documentBoost;
 
+    if (_childDocuments != null) {
       clone._childDocuments = new ArrayList<SolrInputDocument>(_childDocuments.size());
       for (SolrInputDocument child : _childDocuments) {
         clone._childDocuments.add(child.deepCopy());
       }
+    }
     
     return clone;
   }
@@ -277,6 +277,9 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
   }
   
   public void addChildDocument(SolrInputDocument child) {
+   if (_childDocuments == null) {
+     _childDocuments = new ArrayList<SolrInputDocument>();
+   }
     _childDocuments.add(child);
   }
   
@@ -286,6 +289,7 @@ public class SolrInputDocument implements Map<String,SolrInputField>, Iterable<S
     }
   }
 
+  /** Returns the list of child documents, or null if none. */
   public List<SolrInputDocument> getChildDocuments() {
     return _childDocuments;
   }

solr/solrj/src/java/org/apache/solr/common/util/JavaBinCodec.java

@@ -387,7 +387,8 @@ public class JavaBinCodec {
 
   public void writeSolrInputDocument(SolrInputDocument sdoc) throws IOException {
     writeTag(SOLRINPUTDOC, sdoc.size());
-    writeTag(SOLRINPUTDOC_CHILDS, sdoc.getChildDocuments().size());    
+    List<SolrInputDocument> children = sdoc.getChildDocuments();
+    writeTag(SOLRINPUTDOC_CHILDS, children==null ? 0 : children.size());
     writeFloat(sdoc.getDocumentBoost());
     for (SolrInputField inputField : sdoc.values()) {
       if (inputField.getBoost() != 1.0f) {
@@ -396,10 +397,12 @@ public class JavaBinCodec {
       writeExternString(inputField.getName());
       writeVal(inputField.getValue());
     }
+    if (children != null) {
       for (SolrInputDocument child : sdoc.getChildDocuments()) {
         writeSolrInputDocument(child);
       }
     }
+  }
 
 
   public Map<Object,Object> readMap(DataInputInputStream dis)