Support for storing large strings as multiple attribute/value pairs

core/pom.xml

@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>SimpleJPA</groupId>
   <artifactId>SimpleJPA</artifactId>
-  <version>1.6-SNAPSHOT</version>
+  <version>1.6.1-SNAPSHOT</version>
   <name>SimpleJPA</name>
   <url>http://code.google.com/p/simplejpa</url>
   <scm>

core/src/main/java/com/spaceprogram/simplejpa/ObjectBuilder.java

@@ -15,6 +15,7 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.logging.Logger;
@@ -26,6 +27,7 @@
  * 
  * Additional Contributions
  *  - Yair Ben-Meir reformy@gmail.com
+ *  - Michael Balser michael@die-balsers.de
  */
 public class ObjectBuilder {
 
@@ -165,14 +167,37 @@ private static String getIdForManyToOne(EntityManagerSimpleJPA em, Method getter
 
     private static String getValueToSet(List<Attribute> atts, String propertyName, String columnName) {
         if(columnName != null) propertyName = columnName;
+        // Retrieve all matching attributes.
+        List<Attribute> matchingAtts = new ArrayList<Attribute>();
         for (Attribute att : atts) {
             String attName = att.getName();
             if (attName.equals(propertyName)) {
-                String val = att.getValue();
-                return val;
+            	matchingAtts.add(att);
             }
         }
-        return null;
+        if (matchingAtts.size() == 0) {
+        	return null;
+        } else if (matchingAtts.size() == 1) {
+        	// Value has not been split into multiple chunks.
+        	// Simply return value.
+            String val = matchingAtts.get(0).getValue();
+            return val;
+        } else {
+        	// Value has been split into multiple chunks.
+        	// 1. Order chunks according to attached counter.
+    		String[] chunks = new String[matchingAtts.size()];
+        	for (int i = 0; i < matchingAtts.size(); i ++) {
+        		String chunk = matchingAtts.get(i).getValue();
+        		int counter = Integer.parseInt("" + chunk.charAt(chunk.length() - 4)) * 1000 + Integer.parseInt("" + chunk.charAt(chunk.length() - 3)) * 100 + Integer.parseInt("" + chunk.charAt(chunk.length() - 2)) * 10 + Integer.parseInt("" + chunk.charAt(chunk.length() - 1));
+        		chunks[counter] = chunk.substring(0, chunk.length() - 4);
+        	}
+        	// 2. Append chunks.
+        	StringBuffer val = new StringBuffer();
+        	for (int i = 0; i < chunks.length; i ++) {
+        		val.append(chunks[i]);
+        	}
+        	return val.toString();
+        }
     }
 
 

core/src/main/java/com/spaceprogram/simplejpa/operations/Save.java

@@ -1,50 +1,55 @@
 package com.spaceprogram.simplejpa.operations;
 
-import com.amazonaws.AmazonClientException;
-import com.amazonaws.services.s3.AmazonS3;
-import com.amazonaws.services.simpledb.model.Attribute;
-import com.amazonaws.services.simpledb.model.DeleteAttributesRequest;
-import com.amazonaws.services.simpledb.model.Item;
-import com.amazonaws.services.simpledb.model.PutAttributesRequest;
-import com.amazonaws.services.simpledb.model.ReplaceableAttribute;
-import com.spaceprogram.simplejpa.AnnotationInfo;
-import com.spaceprogram.simplejpa.DomainHelper;
-import com.spaceprogram.simplejpa.EntityManagerFactoryImpl;
-import com.spaceprogram.simplejpa.EntityManagerSimpleJPA;
-import com.spaceprogram.simplejpa.LazyInterceptor;
-import com.spaceprogram.simplejpa.NamingHelper;
-import net.sf.cglib.proxy.Factory;
-
-import javax.persistence.EnumType;
-import javax.persistence.Enumerated;
-import javax.persistence.Id;
-import javax.persistence.Lob;
-import javax.persistence.ManyToOne;
-import javax.persistence.OneToMany;
-import javax.persistence.PersistenceException;
-import javax.persistence.PostPersist;
-import javax.persistence.PostUpdate;
-import javax.persistence.PrePersist;
-import javax.persistence.PreUpdate;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.ObjectOutputStream;
+import java.io.UnsupportedEncodingException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.Callable;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import javax.persistence.EnumType;
+import javax.persistence.Enumerated;
+import javax.persistence.Id;
+import javax.persistence.Lob;
+import javax.persistence.ManyToOne;
+import javax.persistence.OneToMany;
+import javax.persistence.PersistenceException;
+import javax.persistence.PostPersist;
+import javax.persistence.PostUpdate;
+import javax.persistence.PrePersist;
+import javax.persistence.PreUpdate;
+
+import net.sf.cglib.proxy.Factory;
+
+import com.amazonaws.AmazonClientException;
+import com.amazonaws.services.s3.AmazonS3;
+import com.amazonaws.services.simpledb.model.Attribute;
+import com.amazonaws.services.simpledb.model.DeleteAttributesRequest;
+import com.amazonaws.services.simpledb.model.PutAttributesRequest;
+import com.amazonaws.services.simpledb.model.ReplaceableAttribute;
+import com.spaceprogram.simplejpa.AnnotationInfo;
+import com.spaceprogram.simplejpa.EntityManagerFactoryImpl;
+import com.spaceprogram.simplejpa.EntityManagerSimpleJPA;
+import com.spaceprogram.simplejpa.LazyInterceptor;
+import com.spaceprogram.simplejpa.NamingHelper;
+
 /**
  * User: treeder
  * Date: Apr 1, 2008
  * Time: 11:51:16 AM
+ * 
+ * Additional Contributions
+ *  - Michael Balser michael@die-balsers.de
  */
 public class Save implements Callable {
     private static Logger logger = Logger.getLogger(Save.class.getName());
@@ -200,8 +205,35 @@ else if(getter.getAnnotation(Id.class) != null)
             }
             else {
                 String toSet = ob != null ? em.padOrConvertIfRequired(ob) : "";
-                // todo: throw an exception if this is going to exceed maximum size, suggest using @Lob
-                attsToPut.add(new ReplaceableAttribute(columnName, toSet, true));
+
+                try {
+                	// Check size of encoded value.
+                	byte[] bytes = toSet.getBytes("UTF-8");
+                	if (bytes.length > 1024) {
+                        // Maximum size is exceeded; split value into multiple chunks.
+                		int i = 0, pos = 0;
+                		while (pos < bytes.length) {
+                			int size = 1020;
+                			// Beware: do not split encoded characters.
+                			// (Additional bytes of an encoded character follow the pattern 10xxxxxx.)
+                			while (pos + size < bytes.length && (bytes[pos + size] & 0xc0) == 0x80) {
+                				size --;
+                			}
+                			String chunk = new String(Arrays.copyOfRange(bytes, pos, Math.min(pos + size, bytes.length)), "UTF-8");
+                			// Add four digit counter.
+                			String counter = Integer.toString(i / 1000 % 10) + Integer.toString(i / 100 % 10) + Integer.toString(i / 10 % 10) + Integer.toString(i % 10);
+                            attsToPut.add(new ReplaceableAttribute(columnName, chunk + counter, i == 0));
+                            i ++;
+                            pos += size;
+                		}
+                	} else {
+                		// Simply store string as single value.
+                        attsToPut.add(new ReplaceableAttribute(columnName, toSet, true));
+                	}
+                } catch (UnsupportedEncodingException x) {
+                    // should never happen
+                    throw new PersistenceException("Encoding 'UTF-8' is not supported!", x);
+                }
             }
         }
 

core/src/test/java/com/spaceprogram/simplejpa/SplitValueTests.java

@@ -0,0 +1,77 @@
+package com.spaceprogram.simplejpa;
+
+import javax.persistence.EntityManager;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+public class SplitValueTests extends BaseTestClass {
+
+	private void doTest(String value) {
+        EntityManager em = factory.createEntityManager();
+        MyTestObject object = new MyTestObject();
+        object.setName(value);
+        em.persist(object);
+        em.close();
+
+        em = factory.createEntityManager();
+        object = em.find(MyTestObject.class, object.getId());
+        Assert.assertEquals(value, object.getName());
+        em.remove(object);
+        em.close();
+	}
+
+	@Test
+	public void testSmallStringValue() {
+		doTest("Test");
+	}
+
+	@Test
+	public void testMaximumValueWithNoSplitting() {
+		StringBuffer s = new StringBuffer();
+		for (int i = 0; i < 1024; i ++) {
+			s.append((char) ('a' + i % 26));
+		}
+		doTest(s.toString());
+	}
+
+	@Test
+	public void testMinimumValueWithSplitting() {
+		StringBuffer s = new StringBuffer();
+		for (int i = 0; i < 1025; i ++) {
+			s.append((char) ('a' + i % 26));
+		}
+		doTest(s.toString());
+	}
+
+	@Test
+	public void testValueWithLargeNumberOfSplits() {
+		StringBuffer s = new StringBuffer();
+		for (int i = 0; i < 1024 * 12 + 1; i ++) {
+			s.append((char) ('a' + i % 26));
+		}
+		doTest(s.toString());
+	}
+
+	@Test
+	public void testValueWithSpecialCharactersAtEvenOffset() {
+		StringBuffer s = new StringBuffer();
+		for (int i = 0; i < 1024 * 2; i ++) {
+			s.append('\u00e4');
+		}
+		doTest(s.toString());
+	}
+
+
+	@Test
+	public void testValueWithSpecialCharactersAtOddOffset() {
+		StringBuffer s = new StringBuffer();
+		s.append('a');
+		for (int i = 0; i < 1024 * 2; i ++) {
+			s.append('\u00e4');
+		}
+		doTest(s.toString());
+	}
+
+}