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javadoc

This commit is contained in:
Andy Clement 2008-08-16 01:41:13 +00:00
parent 3d4158ea51
commit 2d732ba398
1 changed files with 18 additions and 18 deletions
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36
org.springframework.expression/src/main/java/org/springframework/expression/CacheablePropertyAccessor.java
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@ -1,22 +1,21 @@
package org.springframework.expression;
// TODO (asc) Do we need a 'caching is allowed' option to be configurable at parse time?
/**
* A CacheablePropertyAccessor is an optimized PropertyAccessor where the two parts of accessing the
* property are separated: (1) resolving the property and (2) retrieving its value. In some cases there is
* a large cost to discovering which property an expression refers to and once discovered it will
* always resolve to the same property. In these situations a CacheablePropertyAccessor enables the
* resolution to be done once and a reusable object (an executor) returned that can be called over and
* over to retrieve the property value without going through resolution again.
* A CacheablePropertyAccessor is an optimized PropertyAccessor where the two parts of accessing the property are
* separated: (1) resolving the property and (2) retrieving its value. In some cases there is a large cost to
* discovering which property an expression refers to and once discovered it will always resolve to the same property.
* In these situations a CacheablePropertyAccessor enables the resolution to be done once and a reusable object (an
* executor) returned that can be called over and over to retrieve the property value without going through resolution
* again.
* <p>
*
*
* @author Andy Clement
*/
public abstract class CacheablePropertyAccessor implements PropertyAccessor {
/**
* Attempt to resolve the named property and return an executor that can be called to
* get the value of that property. Return null if the property cannot be resolved.
* Attempt to resolve the named property and return an executor that can be called to get the value of that
* property. Return null if the property cannot be resolved.
*
* @param context the evaluation context
* @param target the target upon which the property is being accessed
@ -26,8 +25,8 @@ public abstract class CacheablePropertyAccessor implements PropertyAccessor {
public abstract PropertyReaderExecutor getReaderAccessor(EvaluationContext context, Object target, Object name);
/**
* Attempt to resolve the named property and return an executor that can be called to
* set the value of that property. Return null if the property cannot be resolved.
* Attempt to resolve the named property and return an executor that can be called to set the value of that
* property. Return null if the property cannot be resolved.
*
* @param context the evaluation context
* @param target the target upon which the property is being accessed
@ -37,21 +36,22 @@ public abstract class CacheablePropertyAccessor implements PropertyAccessor {
public abstract PropertyWriterExecutor getWriterAccessor(EvaluationContext context, Object target, Object name);
// Implementation of PropertyAccessor follows, based on the resolver/executor model
public final boolean canRead(EvaluationContext context, Object target, Object name) throws AccessException {
return getReaderAccessor(context,target,name) != null;
return getReaderAccessor(context, target, name) != null;
}
public final boolean canWrite(EvaluationContext context, Object target, Object name) throws AccessException {
return getWriterAccessor(context,target,name) != null;
return getWriterAccessor(context, target, name) != null;
}
public final Object read(EvaluationContext context, Object target, Object name) throws AccessException {
return getReaderAccessor(context,target,name).execute(context,target);
return getReaderAccessor(context, target, name).execute(context, target);
}
public final void write(EvaluationContext context, Object target, Object name, Object newValue) throws AccessException {
getWriterAccessor(context,target,name).execute(context,target,newValue);
public final void write(EvaluationContext context, Object target, Object name, Object newValue)
throws AccessException {
getWriterAccessor(context, target, name).execute(context, target, newValue);
}
}