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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1999
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package netscape.ldap;

/**
 * Manages search results, references and responses returned on one or 
 * more search requests
 *
 */
public class LDAPSearchListener extends LDAPMessageQueue {

    static final long serialVersionUID = -7163312406176592277L;
    // this instance variable is only for cache purpose
    private Long m_key = null;
    private LDAPSearchConstraints m_constraints;

    /**
     * Constructs a LDAP search listener.
     * @param asynchOp a boolean flag indicating whether the object is used 
     * for asynchronous LDAP operations
     * @param cons LDAP search constraints
     * @see netscape.ldap.LDAPAsynchronousConnection
     */
    LDAPSearchListener ( boolean asynchOp,
                         LDAPSearchConstraints cons ) {
        super ( asynchOp );
        m_constraints = cons;
    }

    /**
     * Block until all results are in. Used for synchronous search with 
     * batch size of zero.
     * @return search response message.
     * @exception Network exception error
     */
    LDAPResponse completeSearchOperation () throws LDAPException{
        return completeRequest();
    }


    /**
     * Blocks until a search result, reference or response is available,
     * or until all operations associated with the object have completed
     * or been canceled.
     *
     * @return a search result, search reference, search response message,
     * or null if there are no more outstanding requests. 
     * @exception LDAPException Network error exception
     * @exception LDAPInterruptedException The invoking thread was interrupted
     * @see LDAPResponse
     * @see LDAPSearchResult
     * @see LDAPSearchResultReference
     */
    public LDAPMessage getResponse () throws LDAPException{
        return nextMessage();
    }


    /**
     * Override nextMessage to wake up the LDAPConnThread if 
     *  backlog limit has been reached 
     */
    LDAPMessage nextMessage()  throws LDAPException{
        LDAPMessage result = super.nextMessage();

        // Notify LDAPConnThread to wake up if backlog limit has been reached
        if (result instanceof LDAPSearchResult || result instanceof LDAPSearchResultReference) {
            LDAPConnThread connThread = getConnThread(result.getMessageID());
            if (connThread != null) {
                connThread.resultRetrieved();
            }
        }
        
        return result;
    }

    /**
     * Merge two response listeners.
     * Move/append the content from another response listener to this one.
     * <P>
     * To be used for synchronization of asynchronous LDAP operations where
     * requests are sent by one thread but processed by another one.
     * <P>
     * A client may be implemented in such a way that one thread makes LDAP
     * requests and calls l.getMessageIDs(), while another thread
     * is responsible for
     * processing of responses (call l.getResponse()). Both threads are using
     * the same listener objects. In such a case, a race
     * condition may occur, where a LDAP response message is retrieved and
     * the request terminated (request ID removed) before the first thread
     * has a chance to execute l.getMessageIDs().
     * The proper way to handle this scenario is to create a separate listener
     * for each new request, and after l.getMessageIDs() has been invoked,
     * merge the new request with the existing one.
     * @param listener2 the listener with which to merge
     */
    public void merge(LDAPSearchListener listener2) {
        super.merge(listener2);
    }
    
    /**
     * Reports true if a response has been received from the server.
     *
     * @return a flag indicating whether the response message queue is empty.
     */
    public boolean isResponseReceived() {
        return super.isMessageReceived();
    }

    /**
     * Returns message IDs for all outstanding requests
     * @return message ID array.
     */
    public int[] getMessageIDs() {
        return super.getMessageIDs();
    }
    
    /**
     * Return the search constraints used to create this object.
     * @return the search constraints used to create this object.
     */
    LDAPSearchConstraints getSearchConstraints() {
        return m_constraints;
    }

    /**
     * Set new search constraints object.
     * @param cons LDAP search constraints
     */
     void setSearchConstraints(LDAPSearchConstraints cons) {
        m_constraints = cons;
    }

    /**
     * Resets the state of this object, so it can be recycled.
     * Used by LDAPConnection synchronous operations.
     */
    void reset () {
        super.reset();
        m_constraints = null;
    }
    
    /**
     * Set the key of the cache entry. The listener needs to know this value
     * when the results get processed in the queue. After the results have been
     * saved in the vector, then the key and a vector of results are put in
     * the cache.
     * @param key the key of the cache entry
     */
    void setKey(Long key) {
        m_key = key;
    }

    /**
     * Get the key of the cache entry.
     * @return the key of the cache entry.
     */
    Long getKey() {
        return m_key;
    }
}
