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Oracle® Coherence Java API Reference Release 3.6.0.0 E15725-01 |
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java.lang.Object
com.tangosol.util.Base
com.tangosol.util.processor.AbstractProcessor
com.tangosol.util.processor.ConditionalPut
public class ConditionalPut
ConditionalPut is an EntryProcessor that performs an Entry.setValue
operation if the specified condition is satisfied. <p/> While the ConditionalPut processing could be implemented via direct key-based QueryMap operations, it is more efficient and enforces concurrency control without explicit locking. <p/> For example, the following operations are functionally equivalent to methods of the ConcurrentMap interface (available with JDK 1.5).
InvocableMap | ConcurrentMap |
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filter = PresentFilter.INSTANCE; cache.invoke(key, new ConditionalPut(filter, value); | cache.replace(key, value); |
filter = new NotFilter(PresentFilter.INSTANCE); cache.invoke(key, new ConditionalPut(filter, value)); | cache.putIfAbsent(key, value); |
filter = new EqualsFilter(IdentityExtractor.INSTANCE, valueOld); cache.invoke(key, new ConditionalPut(filter, valueNew)); | cache.replace(key, valueOld, valueNew); |
<p/> Obviously, using more specific, fine-tuned filters (rather than ones based on the IdentityExtractor) may provide additional flexibility and efficiency allowing the put operation to be performed conditionally on values of specific attributes (or even calculations) instead of the entire object.
Field Summary | |
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protected Filter |
m_filter The underlying filter. |
protected boolean |
m_fReturn Specifies whether or not a return value is required. |
protected Object |
m_oValue Specifies the new value to update an entry with. |
Constructor Summary | |
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ConditionalPut() Default constructor (necessary for the ExternalizableLite interface). |
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ConditionalPut(Filter filter, Object oValue) Construct a ConditionalPut that updates an entry with a new value if and only if the filter applied to the entry evaluates to true. |
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ConditionalPut(Filter filter, Object oValue, boolean fReturn) Construct a ConditionalPut that updates an entry with a new value if and only if the filter applied to the entry evaluates to true. |
Method Summary | |
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boolean |
equals(Object o) Compare the ConditionalPut with another object to determine equality. |
int |
hashCode() Determine a hash value for the ConditionalPut object according to the general Object.hashCode() contract. |
Object |
process(InvocableMap.Entry entry) Process a Map.Entry object. |
Map |
processAll(Set setEntries) Process a Set of InvocableMap.Entry objects. This method is semantically equivalent to: Map mapResults = new ListMap(); for (Iterator iter = setEntries.iterator(); iter.hasNext(); ) { Entry entry = (Entry) iter.next(); mapResults.put(entry.getKey(), process(entry)); } return mapResults;Note: if processAll() call throws an exception, entries that were removed from the setEntries would be considered successfully processed and corresponding changes will be made to the underlying Map. |
void |
readExternal(DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object. |
void |
readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object. |
String |
toString() Return a human-readable description for this ConditionalPut. |
void |
writeExternal(DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object. |
void |
writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object. |
Field Detail |
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protected Filter m_filter
protected Object m_oValue
protected boolean m_fReturn
Constructor Detail |
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public ConditionalPut()
public ConditionalPut(Filter filter, Object oValue)
process(com.tangosol.util.InvocableMap.Entry)
invocation does not return any result.
filter
- the filter to evaluate an entryoValue
- a value to update an entry withpublic ConditionalPut(Filter filter, Object oValue, boolean fReturn)
filter
- the filter to evaluate an entryoValue
- a value to update an entry withfReturn
- specifies whether or not the processor should return the current value in case it has not been updatedMethod Detail |
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public Object process(InvocableMap.Entry entry)
process
in interface InvocableMap.EntryProcessor
entry
- the Entry to processpublic Map processAll(Set setEntries)
Map mapResults = new ListMap(); for (Iterator iter = setEntries.iterator(); iter.hasNext(); ) { Entry entry = (Entry) iter.next(); mapResults.put(entry.getKey(), process(entry)); } return mapResults;Note: if processAll() call throws an exception, entries that were removed from the setEntries would be considered successfully processed and corresponding changes will be made to the underlying Map.
processAll
in interface InvocableMap.EntryProcessor
processAll
in class AbstractProcessor
setEntries
- a Set of InvocableMap.Entry objects to processpublic boolean equals(Object o)
public int hashCode()
Object.hashCode()
contract.public String toString()
public void readExternal(DataInput in) throws IOException
readExternal
in interface ExternalizableLite
in
- the DataInput stream to read data from in order to restore the state of this objectIOException
- if an I/O exception occursNotActiveException
- if the object is not in its initial state, and therefore cannot be deserialized intopublic void writeExternal(DataOutput out) throws IOException
writeExternal
in interface ExternalizableLite
out
- the DataOutput stream to write the state of this object toIOException
- if an I/O exception occurspublic void readExternal(PofReader in) throws IOException
readExternal
in interface PortableObject
in
- the PofReader from which to read the object's stateIOException
- if an I/O error occurspublic void writeExternal(PofWriter out) throws IOException
writeExternal
in interface PortableObject
out
- the PofWriter to which to write the object's stateIOException
- if an I/O error occurs
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Oracle® Coherence Java API Reference Release 3.6.0.0 E15725-01 |
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