src/org/apache/xerces/xni/Augmentations.java

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 *
 * This software consists of voluntary contributions made by many
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 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
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package org.apache.xerces.xni;

/**
 * The Augmentations interface defines a table of additional data that may
 * be passed along the document pipeline. The information can contain extra
 * arguments or infoset augmentations, for example PSVI. This additional
 * information is identified by a String key.
 * <p>
 * <strong>Note:</strong>
 * Methods that receive Augmentations are required to copy the information
 * if it is to be saved for use beyond the scope of the method.
 * The Augmentations content is volatile, and maybe modified by any method in
 * any component in the pipeline. Therefore, methods passed this structure
 * should not save any reference to the structure.
 * 
 * @author Elena Litani, IBM
 */
public interface Augmentations {
    
    
    /**
     * Add additional information identified by a key to the Augmentations structure.
     * 
     * @param key    Identifier, can't be <code>null</code>
     * @param item   Additional information
     *
     * @return the previous value of the specified key in the Augmentations structure,
     *         or <code>null</code> if it did not have one.
     */
    public Object putItem (String key, Object item);


    /**
     * Get information identified by a key from the Augmentations structure
     * 
     * @param key    Identifier, can't be <code>null</code>
     *
     * @return the value to which the key is mapped in the Augmentations structure;
     *         <code>null</code> if the key is not mapped to any value.
     */
    public Object getItem(String key);
    
    
    /**
     * Remove additional info from the Augmentations structure
     * 
     * @param key    Identifier, can't be <code>null</code>
     * @return the previous value of the specified key in the Augmentations structure,
     *         or <code>null</code> if it did not have one.
     */
    public Object removeItem (String key);

    /**
     * Remove all objects from the Augmentations structure.
     */
    public void clear ();

    //
    // REVISIT:
    // provide a way to iterate through all of the items in the augmentations.
    //
}