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

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

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

    public class ConditionalPut

extends AbstractProcessor
implements ExternalizableLite, PortableObject

ConditionalPut is an EntryProcessor that performs an `Entry.setValue` operation if the specified condition is satisfied.

While the ConditionalPut 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 equivalent to methods of the ConcurrentMap interface (available with JDK 1.5).

         InvocableMap
         ConcurrentMap

           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);

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.

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.
`protected java.lang.Object` | `m_oValue` Specifies the new value to update an entry with.

Constructor Summary
`ConditionalPut()` Default constructor (necessary for the ExternalizableLite interface).
`ConditionalPut(Filter filter, java.lang.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.
`ConditionalPut(Filter filter, java.lang.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
`boolean` | `equals(java.lang.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.
`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 ConditionalPut.
`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_oValue

    protected java.lang.Object m_oValue

  Specifies the new value to update an entry with.

### m_fReturn

    protected boolean m_fReturn

  Specifies whether or not a return value is required.

Constructor Detail

### ConditionalPut

    public ConditionalPut()

  Default constructor (necessary for the ExternalizableLite interface).

### ConditionalPut

    public ConditionalPut(Filter filter,
                          java.lang.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. The result of the `process(com.tangosol.util.InvocableMap.Entry)` invocation does not return any result.

  Parameters:
    `filter` - the filter to evaluate an entry
    `oValue` - a value to update an entry with

### ConditionalPut

    public ConditionalPut(Filter filter,
                          java.lang.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. This processor optionally returns the current value as a result of the invocation if it has not been updated (the filter evaluated to false).

  Parameters:
    `filter` - the filter to evaluate an entry
    `oValue` - a value to update an entry with
    `fReturn` - specifies whether or not the processor should return the current value in case it has not been updated

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 ConditionalPut with another object to determine equality.

  Returns:
    true iff this ConditionalPut and the passed object are equivalent ConditionalPut processors

### hashCode

    public int hashCode()

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

  Returns:
    an integer hash value for this ConditionalPut object

### toString

    public java.lang.String toString()

  Return a human-readable description for this ConditionalPut.

  Returns:
    a String description of the ConditionalPut

### 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
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