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Oracle® Coherence Java API Reference
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## com.tangosol.util.processor
Class ConditionalRemove

    java.lang.Object
      com.tangosol.util.Base
          com.tangosol.util.processor.AbstractProcessor
              com.tangosol.util.processor.ConditionalRemove

All Implemented Interfaces:
  ExternalizableLite, PortableObject, InvocableMap.EntryProcessor, java.io.Serializable

    public class ConditionalRemove

extends AbstractProcessor
implements ExternalizableLite, PortableObject

ConditionalRemove is an EntryProcessor that performs an `Entry.remove` operation if the specified condition is satisfied.

While the ConditionalRemove processing could be implemented via direct key-based QueryMap operations, it is more efficient and enforces concurrency control without explicit locking.

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

           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).

Since:
  Coherence 3.2
Author:
  gg 2006.03.15

Field Summary
`protected Filter` | `m_filter` The underlying filter.
`protected boolean` | `m_fReturn` Specifies whether or not a return value is required.

Constructor Summary
`ConditionalRemove()` Default constructor (necessary for the ExternalizableLite interface).
`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.
`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
`boolean` | `equals(java.lang.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.
`java.lang.Object` | `process(InvocableMap.Entry entry)` Process a Map.Entry object.
`java.util.Map` | `processAll(java.util.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;
`void` | `readExternal(java.io.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.
`java.lang.String` | `toString()` Return a human-readable description for this ConditionalRemove.
`void` | `writeExternal(java.io.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

### m_filter

    protected Filter m_filter

  The underlying filter.

### m_fReturn

    protected boolean m_fReturn

  Specifies whether or not a return value is required.

Constructor Detail

### ConditionalRemove

    public ConditionalRemove()

  Default constructor (necessary for the ExternalizableLite interface).

### ConditionalRemove

    public 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. The result of the `process(com.tangosol.util.InvocableMap.Entry)` invocation does not return any result.

  Parameters:
    `filter` - the filter to evaluate an entry

### ConditionalRemove

    public 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. This processor may optionally return the current value as a result of the invocation if it has not been removed (the filter evaluated to false).

  Parameters:
    `filter` - the filter to evaluate an entry
    `fReturn` - specifies whether or not the processor should return the current value if it has not been removed

Method Detail

### process

    public java.lang.Object process(InvocableMap.Entry entry)

  Process a Map.Entry object.

  Specified by:
    `process` in interface `InvocableMap.EntryProcessor`
  Parameters:
    `entry` - the Entry to process
  Returns:
    the result of the processing, if any

### processAll

    public java.util.Map processAll(java.util.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;

  Specified by:
    `processAll` in interface `InvocableMap.EntryProcessor`
  Overrides:
    `processAll` in class `AbstractProcessor`
  Parameters:
    `setEntries` - a read-only Set of InvocableMap.Entry objects to process
  Returns:
    a Map containing the results of the processing, up to one entry for each InvocableMap.Entry that was processed, keyed by the keys of the Map that were processed, with a corresponding value being the result of the processing for each key

### equals

    public boolean equals(java.lang.Object o)

  Compare the ConditionalRemove with another object to determine equality.

  Returns:
    true iff this ConditionalRemove and the passed object are equivalent ConditionalRemove

### hashCode

    public int hashCode()

  Determine a hash value for the ConditionalRemove object according to the general `Object.hashCode()` contract.

  Returns:
    an integer hash value for this ConditionalRemove object

### toString

    public java.lang.String toString()

  Return a human-readable description for this ConditionalRemove.

  Returns:
    a String description of the ConditionalRemove processor

### readExternal

    public void readExternal(java.io.DataInput in)
                      throws java.io.IOException

  Restore the contents of this object by loading the object's state from the passed DataInput object.

  Specified by:
    `readExternal` in interface `ExternalizableLite`
  Parameters:
    `in` - the DataInput stream to read data from in order to restore the state of this object
  Throws:
    `java.io.IOException` - if an I/O exception occurs
    `java.io.NotActiveException` - if the object is not in its initial state, and therefore cannot be deserialized into

### writeExternal

    public void writeExternal(java.io.DataOutput out)
                       throws java.io.IOException

  Save the contents of this object by storing the object's state into the passed DataOutput object.

  Specified by:
    `writeExternal` in interface `ExternalizableLite`
  Parameters:
    `out` - the DataOutput stream to write the state of this object to
  Throws:
    `java.io.IOException` - if an I/O exception occurs

### readExternal

    public void readExternal(PofReader in)
                      throws java.io.IOException

  Restore the contents of a user type instance by reading its state using the specified PofReader object.

  Specified by:
    `readExternal` in interface `PortableObject`
  Parameters:
    `in` - the PofReader from which to read the object's state
  Throws:
    `java.io.IOException` - if an I/O error occurs

### writeExternal

    public void writeExternal(PofWriter out)
                       throws java.io.IOException

  Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

  Specified by:
    `writeExternal` in interface `PortableObject`
  Parameters:
    `out` - the PofWriter to which to write the object's state
  Throws:
    `java.io.IOException` - if an I/O error occurs

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Oracle® Coherence Java API Reference
v3.5.3
E15583-01
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