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/*
 * Copyright (c) 2000, 2022, Oracle and/or its affiliates.
 *
 * Licensed under the Universal Permissive License v 1.0 as shown at
 * https://oss.oracle.com/licenses/upl.
 */

package com.tangosol.util.processor;


import com.tangosol.io.ExternalizableLite;

import com.tangosol.io.pof.PofReader;
import com.tangosol.io.pof.PofWriter;
import com.tangosol.io.pof.PortableObject;

import com.tangosol.util.ClassHelper;
import com.tangosol.util.ExternalizableHelper;
import com.tangosol.util.InvocableMap;
import com.tangosol.util.LiteMap;
import com.tangosol.util.Versionable;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import jakarta.json.bind.annotation.JsonbProperty;


/**
* VersionedPut is an EntryProcessor that assumes that entry values implement
* {@link com.tangosol.util.Versionable} interface and performs an
* {@link com.tangosol.util.InvocableMap.Entry#setValue(Object)
* Entry.setValue} operation if and only if the version of the specified value
* matches to the version of the current value. In case of the match, the
* VersionedPut will increment the version indicator before the value is
* updated.
*
* @see ConditionalPut
* @author gg 2006.05.07; Acknowledgments: Simon Bisson
* @since Coherence 3.2
*/
public class VersionedPut
        extends    AbstractProcessor
        implements ExternalizableLite, PortableObject
    {
    // ----- constructors ---------------------------------------------------

    /**
    * Default constructor (necessary for the ExternalizableLite interface).
    */
    public VersionedPut()
        {
        }

    /**
    * Construct a VersionedPut that updates an entry with a new value if and
    * only if the version of the new value matches to the version of the
    * current entry's value (which must exist).
    * The result of the {@link #process} invocation does not return any
    * result.
    *
    * @param oValue  a Versionable value to update an entry with
    */
    public VersionedPut(V oValue)
        {
        this(oValue, false, false);
        }

    /**
    * Construct a VersionedPut that updates an entry with a new value if and
    * only if the version of the new value matches to the version of the
    * current entry's value. This processor optionally returns the current
    * value as a result of the invocation if it has not been updated (the
    * versions did not match).
    *
    * @param oValue        a value to update an entry with
    * @param fAllowInsert  specifies whether or not an insert should be
    *                      allowed (no currently existing value)
    * @param fReturn       specifies whether or not the processor should
    *                      return the current value in case it has not been
    *                      updated
    */
    public VersionedPut(V oValue, boolean fAllowInsert, boolean fReturn)
        {
        azzert(oValue != null, "null value");

        m_oValue  = oValue;
        m_fInsert = fAllowInsert;
        m_fReturn = fReturn;
        }


    // ----- EntryProcessor interface ---------------------------------------

    /**
    * {@inheritDoc}
    */
    public V process(InvocableMap.Entry entry)
        {
        Object oResult = processEntry(entry, m_oValue, m_fInsert, m_fReturn);
        return oResult == NO_RESULT ? null : (V) oResult;
        }

    /**
    * {@inheritDoc}
    */
    public Map processAll(Set> setEntries)
        {
        Map         mapResult = new LiteMap();
        V           value     = m_oValue;
        boolean     fInsert   = m_fInsert;
        boolean     fReturn   = m_fReturn;

        for (Iterator iter = setEntries.iterator(); iter.hasNext();)
            {
            InvocableMap.Entry entry = (InvocableMap.Entry) iter.next();

            Object oResult = processEntry(entry, value, fInsert, fReturn);

            if (oResult != NO_RESULT)
                {
                mapResult.put(entry.getKey(), oResult);
                }
            }

        return mapResult;
        }


    // ----- Object methods -------------------------------------------------

    /**
    * Compare the VersionedPut with another object to determine equality.
    *
    * @return true iff this VersionedPut and the passed object are
    *         equivalent VersionedPut
    */
    public boolean equals(Object o)
        {
        if (o instanceof VersionedPut)
            {
            VersionedPut that = (VersionedPut) o;
            return equals(this.m_oValue, that.m_oValue)
                &&        this.m_fInsert == that.m_fInsert
                &&        this.m_fReturn == that.m_fReturn;
            }

        return false;
        }

    /**
    * Determine a hash value for the VersionedPut object according to the
    * general {@link Object#hashCode()} contract.
    *
    * @return an integer hash value for this VersionedPut object
    */
    public int hashCode()
        {
        return m_oValue.hashCode() +
            (m_fInsert ? 1 : 2) + (m_fReturn ? 3 : 4);
        }

    /**
    * Return a human-readable description for this VersionedPut.
    *
    * @return a String description of the VersionedPut
    */
    public String toString()
        {
        return ClassHelper.getSimpleName(getClass()) +
            "{Value=" + m_oValue +
            ", InsertAllowed= " + m_fInsert +
            ", ReturnRequired= " + m_fReturn + '}';
        }


    // ----- ExternalizableLite interface -----------------------------------

    /**
    * {@inheritDoc}
    */
    public void readExternal(DataInput in)
            throws IOException
        {
        m_oValue  = (V) ExternalizableHelper.readObject(in);
        m_fInsert = in.readBoolean();
        m_fReturn = in.readBoolean();
        }

    /**
    * {@inheritDoc}
    */
    public void writeExternal(DataOutput out)
            throws IOException
        {
        ExternalizableHelper.writeObject(out, m_oValue);
        out.writeBoolean(m_fInsert);
        out.writeBoolean(m_fReturn);
        }


    // ----- PortableObject interface ---------------------------------------

    /**
    * {@inheritDoc}
    */
    public void readExternal(PofReader in)
            throws IOException
        {
        m_oValue  = (V) in.readObject(0);
        m_fInsert = in.readBoolean(1);
        m_fReturn = in.readBoolean(2);
        }

    /**
    * {@inheritDoc}
    */
    public void writeExternal(PofWriter out)
            throws IOException
        {
        out.writeObject(0, m_oValue);
        out.writeBoolean(1, m_fInsert);
        out.writeBoolean(2, m_fReturn);
        }


    // ----- helper methods -------------------------------------------------

    /**
    * Process the given entry.
    *
    * @param entry     entry the entry to be processed
    * @param oValueNew the new value
    * @param fInsert   specifies whether or not an insert is allowed
    * @param fReturn   specifies whether or not a return value is required
    *
    * @return the result of processing the entry; can be NO_RESULT
    */
    protected Object processEntry(InvocableMap.Entry entry,
                                  V oValueNew,
                                  boolean fInsert,
                                  boolean fReturn)
        {
        V oValueCur = entry.getValue();
        boolean fMatch;

        if (oValueCur == null)
            {
            fMatch = fInsert;
            }
        else
            {
            Comparable verCur = oValueCur.getVersionIndicator();
            Comparable verNew = oValueNew.getVersionIndicator();

            fMatch = verCur.compareTo(verNew) == 0;
            }

        if (fMatch)
            {
            oValueNew.incrementVersion();

            entry.setValue(oValueNew, false);
            return NO_RESULT;
            }

        return fReturn ? oValueCur : NO_RESULT;
        }


    // ----- constants ------------------------------------------------------

    /**
    * Used internally to differentiate between "no result" and a null result.
    * NO_RESULT should never be returned through the public APIs.
    * A value of NO_RESULT may be returned from processEntry() and will
    * never be included in the result map returned from processAll().
    */
    private static final Object NO_RESULT = new Object();

    // ----- data members ---------------------------------------------------

    /**
    * Specifies the new value to update an entry with.
    */
    @JsonbProperty("value")
    protected V m_oValue;

    /**
    * Specifies whether or not an insert is allowed.
    */
    @JsonbProperty("insert")
    protected boolean m_fInsert;

    /**
    * Specifies whether or not a return value is required.
    */
    @JsonbProperty("return")
    protected boolean m_fReturn;
    }




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