Class NullSafeTranslator<P,D>
java.lang.Object
com.googlecode.objectify.impl.translate.NullSafeTranslator<P,D>
- All Implemented Interfaces:
Translator<P,D>
- Direct Known Subclasses:
ClassTranslator
,ProjectionSafeTranslator
public abstract class NullSafeTranslator<P,D> extends Object implements Translator<P,D>
Handles null checking so we don't have to do it everywhere.
- Author:
- Jeff Schnitzer
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionload(D node, LoadContext ctx, Path path)
Loads the content of the specified datastore node, returning the pojo equivalent.protected abstract P
loadSafe(D node, LoadContext ctx, Path path)
Implement this, returning a proper translated valuesave(P pojo, boolean index, SaveContext ctx, Path path)
Translates a pojo (or some component thereof) into a format suitable for storage in the datastore.protected abstract D
saveSafe(P pojo, boolean index, SaveContext ctx, Path path)
Implement this, returning a proper translated value
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Constructor Details
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NullSafeTranslator
public NullSafeTranslator()
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Method Details
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load
Description copied from interface:Translator
Loads the content of the specified datastore node, returning the pojo equivalent.
There is one special return value: If a Result> is returned, the content of the Result will be used instead, but delayed until ctx.done() is called. This happens at the end of a "round" of load operations and is the magic trick that makes populating entity references work efficiently.
- Specified by:
load
in interfaceTranslator<P,D>
- Parameters:
node
- is the part of the native datastore entity tree we are transforming.ctx
- holds state information during an entity load.path
- is the current path to this translator- Returns:
- an assembled pojo corresponding to the node subtree; if null is returned, that is the real value!
- Throws:
SkipException
- if the return value should be abandoned.- See Also:
LoadEngine
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save
Description copied from interface:Translator
Translates a pojo (or some component thereof) into a format suitable for storage in the datastore.- Specified by:
save
in interfaceTranslator<P,D>
- Parameters:
pojo
- is an object from the pojo entity graph; possibly the whole graph or possibly just a leaf field.index
- is whether the instruction so far is to index or not index property valuespath
- is the path that we have taken to get here, which could be long due to re-entrant translators (ie, an embedded pojo that also has a reference to the same class).- Returns:
- something suitable for storage in the datastore.
- Throws:
SkipException
- if the return value should be abandoned
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loadSafe
Implement this, returning a proper translated value- Parameters:
node
- will never be null- Throws:
SkipException
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saveSafe
protected abstract D saveSafe(P pojo, boolean index, SaveContext ctx, Path path) throws SkipExceptionImplement this, returning a proper translated value- Parameters:
pojo
- will never be null- Throws:
SkipException
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