### Multi-Instance Crawling

```java
// Create multiple crawler instances
Crawler crawler1 = container.getComponent("crawler");
crawler1.setSessionId("session1");
crawler1.addUrl("https://site1.com");

Crawler crawler2 = container.getComponent("crawler");  
crawler2.setSessionId("session2");
crawler2.addUrl("https://site2.com");

// Execute concurrently
crawler1.setBackground(true);
crawler2.setBackground(true);

    public void add(final String sessionId, final String url) {
        if (exists(sessionId, url)) {
            return;
        }
        final OpenSearchUrlQueue urlQueue = new OpenSearchUrlQueue();
        urlQueue.setSessionId(sessionId);
        urlQueue.setUrl(url);
        urlQueue.setCreateTime(System.currentTimeMillis());
        urlQueue.setLastModified(0L);
        urlQueue.setDepth(0);

     */
    public String getSessionId() {
        return sessionId;
    }

    /**
     * Sets the session ID.
     * @param sessionId The session ID.
     */
    public void setSessionId(final String sessionId) {
        this.sessionId = sessionId;
    }

    /**
     * Returns the filter type.
     * @return The filter type.
     */
    public String getFilterType() {

                            responseData.setExecutionTime(SystemUtil.currentTimeMillis() - startTime);
                            responseData.setParentUrl(urlQueue.getParentUrl());
                            responseData.setSessionId(crawlerContext.sessionId);

                            if (responseData.getRedirectLocation() == null) {
                                log(logHelper, LogType.PROCESS_RESPONSE, crawlerContext, urlQueue, responseData);

        }

        @Override
        public void setExtendedSecurity(boolean extendedSecurity) {
            // No-op for test
        }

        @Override
        public void setSessionId(long sessionId) {
            // No-op for test
        }

        @Override
        public void reset() {
            this.response = null;
            this.ignoreDisconnect = false;
        }

    public String getSessionId() {
        return sessionId;
    }

    /*
     * (non-Javadoc)
     *
     * @see org.codelibs.fess.crawler.entity.AccessResult#setSessionId(java.lang.String)
     */
    @Override
    public void setSessionId(final String sessionId) {
        this.sessionId = sessionId;
    }

    /*
     * (non-Javadoc)
     *

     */
    public String getSessionId() {
        return sessionId;
    }

    /**
     * Sets the session ID.
     * @param sessionId The session ID.
     */
    public void setSessionId(final String sessionId) {
        this.sessionId = sessionId;
    }

    /**
     * Returns the active thread count.
     * @return The active thread count.
     */

        return this.sessionId;
    }

    /**
     * Sets the session ID for this encrypted message
     *
     * @param sessionId
     *            the session ID to set
     */
    public void setSessionId(final long sessionId) {
        this.sessionId = sessionId;
    }

    @Override
    public int size() {
        return TRANSFORM_HEADER_SIZE;
    }

    @Override

            file.deleteOnExit();
            fileTransformer.setPath(file.getAbsolutePath());

            final Crawler crawler1 = crawlerContainer.getComponent("crawler");
            crawler1.setSessionId(crawler1.getSessionId() + "1");
            crawler1.setBackground(true);
            ((UrlFilterImpl) crawler1.urlFilter).setIncludeFilteringPattern("$1$2$3.*");
            crawler1.addUrl(url1);

     *
     * @return the session identifier
     */
    String getSessionId();

    /**
     * Sets the session identifier.
     *
     * @param sessionId the session identifier
     */
    void setSessionId(String sessionId);

    /**
     * Returns the rule identifier.
     *
     * @return the rule identifier
     */
    String getRuleId();

    /**
     * Sets the rule identifier.
     *