<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <!--NewPage--> <HTML> <HEAD> <!-- Generated by javadoc (build 1.6.0-google-v4) on Wed Feb 01 12:16:01 PST 2012 --> <TITLE> ImplicitTransactionManagementPolicy </TITLE> <META NAME="date" CONTENT="2012-02-01"> <LINK REL ="stylesheet" TYPE="text/css" HREF="../../../../../dev_javadoc.css" TITLE="Style"> <SCRIPT type="text/javascript"> function windowTitle() { if (location.href.indexOf('is-external=true') == -1) { parent.document.title="ImplicitTransactionManagementPolicy"; } } </SCRIPT> <NOSCRIPT> </NOSCRIPT> </HEAD> <BODY BGCOLOR="white" onload="windowTitle();"> <HR> <!-- ========= START OF TOP NAVBAR ======= --> <A NAME="navbar_top"><!-- --></A> <A HREF="#skip-navbar_top" title="Skip navigation links"></A> <TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""> <TR> <TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A NAME="navbar_top_firstrow"><!-- --></A> <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR> </TABLE> </TD> <TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM> </EM> </TD> </TR> <TR> <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../com/google/appengine/api/datastore/IMHandle.Scheme.html" title="enum in com.google.appengine.api.datastore"><B>PREV CLASS</B></A> <A HREF="../../../../../com/google/appengine/api/datastore/Index.html" title="class in com.google.appengine.api.datastore"><B>NEXT CLASS</B></A></FONT></TD> <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../index.html?com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" target="_top"><B>FRAMES</B></A> <A HREF="ImplicitTransactionManagementPolicy.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--> </SCRIPT> <NOSCRIPT> <A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A> </NOSCRIPT> </FONT></TD> </TR> <TR> <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#enum_constant_summary">ENUM CONSTANTS</A> | FIELD | <A HREF="#method_summary">METHOD</A></FONT></TD> <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> DETAIL: <A HREF="#enum_constant_detail">ENUM CONSTANTS</A> | FIELD | <A HREF="#method_detail">METHOD</A></FONT></TD> </TR> </TABLE> <A NAME="skip-navbar_top"></A> <!-- ========= END OF TOP NAVBAR ========= --> <HR> <!-- ======== START OF CLASS DATA ======== --> <H2> <FONT SIZE="-1"> com.google.appengine.api.datastore</FONT> <BR> Enum ImplicitTransactionManagementPolicy</H2> <PRE> java.lang.Object <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by ">java.lang.Enum<<A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A>> <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by "><B>com.google.appengine.api.datastore.ImplicitTransactionManagementPolicy</B> </PRE> <DL> <DT><B>All Implemented Interfaces:</B> <DD>java.io.Serializable, java.lang.Comparable<<A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A>></DD> </DL> <HR> <DL> <DT><PRE>public enum <B>ImplicitTransactionManagementPolicy</B><DT>extends java.lang.Enum<<A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A>></DL> </PRE> <P> Describes the various policies the datastore can follow for implicit transaction management. When deciding which policy to use, keep the following in mind: The datastore will automatically retry operations that fail due to concurrent updates to the same entity group if the operation is not part of a transaction. The datastore will not retry operations that fail due to concurrent updates to the same entity group if the operation is part of a transaction, and will instead immediately throw a <CODE>ConcurrentModificationException</CODE>. If your application needs to perform any sort of intelligent merging when concurrent attempts are made to update the same entity group you probably want <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#AUTO"><CODE>AUTO</CODE></A>, otherwise <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#NONE"><CODE>NONE</CODE></A> is probably acceptable. See <A HREF="../../../../../com/google/appengine/api/datastore/DatastoreService.html" title="interface in com.google.appengine.api.datastore"><CODE>DatastoreService</CODE></A> for a list of operations that perform implicit transaction management. <P> <P> <HR> <P> <!-- =========== ENUM CONSTANT SUMMARY =========== --> <A NAME="enum_constant_summary"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"> <B>Enum Constant Summary</B></FONT></TH> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD><CODE><B><A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#AUTO">AUTO</A></B></CODE> <BR> If a current transaction exists, use it, otherwise create one.</TD> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD><CODE><B><A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#NONE">NONE</A></B></CODE> <BR> If a current transaction exists, use it, otherwise execute without a transaction.</TD> </TR> </TABLE> <!-- ========== METHOD SUMMARY =========== --> <A NAME="method_summary"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"> <B>Method Summary</B></FONT></TH> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"> <CODE>static <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A></CODE></FONT></TD> <TD><CODE><B><A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#valueOf(java.lang.String)">valueOf</A></B>(java.lang.String name)</CODE> <BR> Returns the enum constant of this type with the specified name.</TD> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"> <CODE>static <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A>[]</CODE></FONT></TD> <TD><CODE><B><A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html#values()">values</A></B>()</CODE> <BR> Returns an array containing the constants of this enum type, in the order they are declared.</TD> </TR> </TABLE> <A NAME="methods_inherited_from_class_java.lang.Enum"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"> <TH ALIGN="left"><B>Methods inherited from class java.lang.Enum</B></TH> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD><CODE>compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf</CODE></TD> </TR> </TABLE> <A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"> <TH ALIGN="left"><B>Methods inherited from class java.lang.Object</B></TH> </TR> <TR BGCOLOR="white" CLASS="TableRowColor"> <TD><CODE>getClass, notify, notifyAll, wait, wait, wait</CODE></TD> </TR> </TABLE> <P> <!-- ============ ENUM CONSTANT DETAIL =========== --> <A NAME="enum_constant_detail"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2"> <B>Enum Constant Detail</B></FONT></TH> </TR> </TABLE> <A NAME="NONE"><!-- --></A><H3> NONE</H3> <PRE> public static final <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A> <B>NONE</B></PRE> <DL> <DD>If a current transaction exists, use it, otherwise execute without a transaction. <P> <DL> </DL> </DL> <HR> <A NAME="AUTO"><!-- --></A><H3> AUTO</H3> <PRE> public static final <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A> <B>AUTO</B></PRE> <DL> <DD>If a current transaction exists, use it, otherwise create one. The transaction will be committed before the method returns if the datastore operation completes successfully and rolled back if the datastore operation does not complete successfully. No matter the type or quantity of entities provided, only one transaction will be created. This means that if you pass entities that belong to multiple entity groups into one of these methods and you have this policy enabled, you will receive an exception because transactions do not function across entity groups. <P> <DL> </DL> </DL> <!-- ============ METHOD DETAIL ========== --> <A NAME="method_detail"><!-- --></A> <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""> <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"> <TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2"> <B>Method Detail</B></FONT></TH> </TR> </TABLE> <A NAME="values()"><!-- --></A><H3> values</H3> <PRE> public static <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A>[] <B>values</B>()</PRE> <DL> <DD>Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: <pre> for (ImplicitTransactionManagementPolicy c : ImplicitTransactionManagementPolicy.values()) System.out.println(c); </pre> <P> <DD><DL> <DT><B>Returns:</B><DD>an array containing the constants of this enum type, in the order they are declared</DL> </DD> </DL> <HR> <A NAME="valueOf(java.lang.String)"><!-- --></A><H3> valueOf</H3> <PRE> public static <A HREF="../../../../../com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" title="enum in com.google.appengine.api.datastore">ImplicitTransactionManagementPolicy</A> <B>valueOf</B>(java.lang.String name)</PRE> <DL> <DD>Returns the enum constant of this type with the specified name. The string must match <I>exactly</I> an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.) <P> <DD><DL> <DT><B>Parameters:</B><DD><CODE>name</CODE> - the name of the enum constant to be returned. <DT><B>Returns:</B><DD>the enum constant with the specified name <DT><B>Throws:</B> <DD><CODE>java.lang.IllegalArgumentException</CODE> - if this enum type has no constant with the specified name <DD><CODE>java.lang.NullPointerException</CODE> - if the argument is null</DL> </DD> </DL> <!-- ========= END OF CLASS DATA ========= --> <HR> <!-- ======= START OF BOTTOM NAVBAR ====== --> <A NAME="navbar_bottom"><!-- --></A> <A HREF="#skip-navbar_bottom" title="Skip navigation links"></A> <TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""> <TR> <TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A NAME="navbar_bottom_firstrow"><!-- --></A> <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR> </TABLE> </TD> <TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM> </EM> </TD> </TR> <TR> <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../com/google/appengine/api/datastore/IMHandle.Scheme.html" title="enum in com.google.appengine.api.datastore"><B>PREV CLASS</B></A> <A HREF="../../../../../com/google/appengine/api/datastore/Index.html" title="class in com.google.appengine.api.datastore"><B>NEXT CLASS</B></A></FONT></TD> <TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../index.html?com/google/appengine/api/datastore/ImplicitTransactionManagementPolicy.html" target="_top"><B>FRAMES</B></A> <A HREF="ImplicitTransactionManagementPolicy.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--> </SCRIPT> <NOSCRIPT> <A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A> </NOSCRIPT> </FONT></TD> </TR> <TR> <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#enum_constant_summary">ENUM CONSTANTS</A> | FIELD | <A HREF="#method_summary">METHOD</A></FONT></TD> <TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> DETAIL: <A HREF="#enum_constant_detail">ENUM CONSTANTS</A> | FIELD | <A HREF="#method_detail">METHOD</A></FONT></TD> </TR> </TABLE> <A NAME="skip-navbar_bottom"></A> <!-- ======== END OF BOTTOM NAVBAR ======= --> <HR> </BODY> </HTML>