org.directwebremoting.io.ItemUpdate Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.

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/*
 * Copyright 2005 Joe Walker
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.directwebremoting.io;

/**
 * Analogous to a {@link java.util.Map.Entry} that we use to pass objects that
 * have been stored in a {@link org.directwebremoting.datasync.StoreProvider} to
 * the Internet.
 * TODO: Consider if we should add version field to this so we can add some sort
 * of pessimistic locking to updates.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class ItemUpdate
{
    /**
     * Create an Item with its ID and data.
     */
    public ItemUpdate(String itemId, String attribute, RawData newValue)
    {
        this.itemId = itemId;
        this.attribute = attribute;
        this.newValue = newValue;
    }

    /**
     * Accessor for the primary key for this Object.
     * Clearly not all database primary keys are Strings, my current feeling is
     * that the majority of database primary keys can either be simply mapped to
     * strings, or are a bad idea anyway.
     * Warning: It would be a bad idea to expose database primary keys
     * directly to the Internet anyway, so some form of mapping is required.
     * @return The primary key for this Object
     */
    public String getItemId()
    {
        return itemId;
    }

    /**
     * Accessor for the property that we want to change on the Object with the
     * ID given in itemId.
     */
    public String getAttribute()
    {
        return attribute;
    }

    /**
     * Accessor for the value for the attribute that we want to
     * change on the Object with the ID given in itemId.
     */
    public RawData getNewValue()
    {
        return newValue;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode()
    {
        return 4783 + itemId.hashCode();
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj)
    {
        if (obj == null)
        {
            return false;
        }

        if (obj == this)
        {
            return true;
        }

        if (!this.getClass().equals(obj.getClass()))
        {
            return false;
        }

        ItemUpdate that = (ItemUpdate) obj;

        if (!this.itemId.equals(that.itemId))
        {
            return false;
        }

        return true;
    }

    /**
     * @see #getItemId
     */
    private final String itemId;

    /**
     * @see #getAttribute
     */
    private final String attribute;

    /**
     * @see #getNewValue
     */
    private final RawData newValue;
}