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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.ConditionalRemove
public class ConditionalRemove
ConditionalRemove is an EntryProcessor that performs an Entry.remove
operation if the specified condition is satisfied. <p/> While the ConditionalRemove 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 similar, but the InvocableMap versions (a) perform significantly better for partitioned caches; (b) provide all necessary concurrency control (which is ommited from the QueryMap examples):
InvocableMap | QueryMap |
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cache.invoke(key, new ConditionalRemove(filter)); (*) | if (filter.evaluate(cache.get(key)) cache.remove(key); |
cache.invokeAll(setKeys, new ConditionalRemove(filter)); | for (Object key : setKeys) if (filter.evaluate(cache.get(key)) cache.remove(key); |
cache.invokeAll(filter1, new ConditionalRemove(filter2); | for (Object key : cache.setKeys(filter1)) if (filter2.evaluate(cache.get(key)) cache.remove(key); |
cache.invokeAll(filter, new ConditionalRemove(AlwaysFilter.INSTANCE)); | Set setKeys = cache.keySet(filter); cache.keySet().removeAll(setKeys); |
(*) If the filter is assigned as the following: filter = new EqualsFilter(IdentityExtractor.INSTANCE, oValue);
this operation also becomes functionally equivalent to the remove method of the ConcurrentMap interface (available with JDK 1.5).
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. |
Constructor Summary | |
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ConditionalRemove() Default constructor (necessary for the ExternalizableLite interface). |
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ConditionalRemove(Filter filter) Construct a ConditionalRemove processor that removes an InvocableMap entry if and only if the filter applied to the entry evaluates to true. |
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ConditionalRemove(Filter filter, boolean fReturn) Construct a ConditionalRemove processor that removes an InvocableMap entry 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 ConditionalRemove with another object to determine equality. |
int |
hashCode() Determine a hash value for the ConditionalRemove 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 ConditionalRemove. |
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 boolean m_fReturn
Constructor Detail |
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public ConditionalRemove()
public ConditionalRemove(Filter filter)
process(com.tangosol.util.InvocableMap.Entry)
invocation does not return any result.
filter
- the filter to evaluate an entrypublic ConditionalRemove(Filter filter, boolean fReturn)
filter
- the filter to evaluate an entryfReturn
- specifies whether or not the processor should return the current value if it has not been removedMethod 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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