gt:         if (input != null) {
context: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * For further information about Alkacon Software GmbH, please see the
   * company website: http://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: http://www.opencms.org
   * 
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.jsp.util;
  
  import org.opencms.file.CmsObject;
  import org.opencms.file.CmsResource;
  import org.opencms.relations.CmsLink;
  import org.opencms.relations.CmsRelationType;
  import org.opencms.staticexport.CmsLinkManager;
  import org.opencms.util.CmsFileUtil;
  import org.opencms.util.CmsMacroResolver;
  import org.opencms.util.CmsStringUtil;
  import org.opencms.util.CmsUUID;
  import org.opencms.util.I_CmsMacroResolver;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Resolves link macros for jsp pages.<p>
   * 
   * The only supported macro is the 'link' macro.<p>
   * 
   * @since 6.5.4 
   */
  public class CmsJspLinkMacroResolver implements I_CmsMacroResolver {
  
      /** Identifier for the link macro separator. */
      public static final char KEY_SEPARATOR = ':';
  
      /** Identifier for the link macro name. */
      public static final String MACRO_LINK = "link:";
  
      /** Identifier for the link macro name. */
      public static final String MACRO_LINK_STRONG = "link.strong:";
  
      /** Identifier for the link macro name. */
      public static final String MACRO_LINK_WEAK = "link.weak:";
  
      /** Identifier for link commands. */
      public static final String[] VALUE_NAME_ARRAY = {MACRO_LINK, MACRO_LINK_WEAK, MACRO_LINK_STRONG};
  
      /** The link commands wrapped in a List. */
      public static final List<String> VALUE_NAMES = Collections.unmodifiableList(Arrays.asList(VALUE_NAME_ARRAY));
  
      /** The cms context. */
      private CmsObject m_cms;
  
      /** 
       * If <code>true</code> the macros get really resolved to valid vfs paths, 
       * otherwise only the path/id in the macros are updated. 
       */
      private boolean m_forRfs;
  
      /** The jsp root path. */
      private String m_jspRootPath;
  
      /** The list of links. */
      private List<CmsLink> m_links = new ArrayList<CmsLink>();
  
      /**
       * Default constructor.<p>
       * 
       * @param cms the cms context
       * @param jspRootPath the (optional) jsp root path, needed for saving from the editor to resolve relative links 
       * @param forRfs Only if <code>true</code> the macros get really resolved to valid vfs paths
       */
      public CmsJspLinkMacroResolver(CmsObject cms, String jspRootPath, boolean forRfs) {
  
          m_cms = cms;
          m_forRfs = forRfs;
          m_jspRootPath = jspRootPath;
      }
  
      /**
       * Returns the links.<p>
       *
       * @return the links
       */
      public List<CmsLink> getLinks() {
  
          return m_links;
      }
  
      /**
       * @see org.opencms.util.I_CmsMacroResolver#getMacroValue(java.lang.String)
       */
      public String getMacroValue(String macro) {
  
          String path = null;
          String id = null;
  
          // validate macro command
          Iterator<String> it = VALUE_NAMES.iterator();
          while (it.hasNext()) {
              String cmd = it.next().toString();
              if (macro.startsWith(cmd)) {
                  // a macro was found
                  path = macro.substring(cmd.length());
                  macro = cmd;
                  break;
              }
          }
          if (path == null) {
              // this is an unknown macro, ignore it
              return null;
          }
  
          // we do have a valid link macro now, parse path and id
          int pos = path.indexOf(KEY_SEPARATOR);
          if ((pos > -1) && (path.length() > pos + 1)) {
              id = path.substring(pos + 1);
          }
          if (pos > -1) {
              path = path.substring(0, pos);
          }
  
          // check the id
          CmsUUID uuid = null;
          if (CmsStringUtil.isEmptyOrWhitespaceOnly(id)) {
              if (path != null) {
                  // try to use the path as an id (in case there is only an id)
                  id = path;
              } else {
                  id = null;
              }
          }
          if (id != null) {
              try {
                  uuid = new CmsUUID(id);
              } catch (Exception e) {
                  // ignore
              }
          }
  
          // rewrite the path
          if ((path == null) || (path.trim().length() == 0)) {
              path = null;
          } else {
              boolean isAbsolute = (path.charAt(0) == '/');
              path = CmsFileUtil.normalizePath(path, '/');
              if (!isAbsolute) {
                  path = path.substring(1);
              }
              if (isAbsolute && !path.startsWith(m_cms.getRequestContext().getSiteRoot())) {
                  // add the site root if needed
                  path = m_cms.getRequestContext().addSiteRoot(path);
              } else if (m_jspRootPath != null) {
                  // get the site aware absolute path
                  path = CmsLinkManager.getAbsoluteUri(path, CmsResource.getParentFolder(m_jspRootPath));
              }
          }
  
          // check the relation type
          CmsRelationType type = CmsRelationType.JSP_WEAK;
          if (macro == MACRO_LINK_STRONG) {
              type = CmsRelationType.JSP_STRONG;
          }
  
          // get the link object
          CmsLink link = new CmsLink("link0", type, uuid, path, true);
          link.checkConsistency(m_cms); // update id/path
          m_links.add(link);
  
          if (m_forRfs) {
              // return the current correct link path 
              return m_cms.getRequestContext().removeSiteRoot(link.getTarget());
          } else {
              // rewrite the macro with the right absolute path and id 
              StringBuffer newMacro = new StringBuffer(128);
              newMacro.append(I_CmsMacroResolver.MACRO_DELIMITER);
              newMacro.append(I_CmsMacroResolver.MACRO_START);
              newMacro.append(macro);
              newMacro.append(link.getSitePath());
              if ((link.getStructureId() != null) && !link.getStructureId().isNullUUID()) {
                  newMacro.append(KEY_SEPARATOR).append(link.getStructureId());
              }
              newMacro.append(I_CmsMacroResolver.MACRO_END);
              return newMacro.toString();
          }
      }
  
      /**
       * @see org.opencms.util.I_CmsMacroResolver#isKeepEmptyMacros()
       */
      public boolean isKeepEmptyMacros() {
  
          return true;
      }
  
      /**
       * Resolves the JSP link management macros in the given input.<p>
       * 
       * Calls <code>{@link #resolveMacros(String)}</code> once for each macro in the input.
       * This means "nested" macros are not supported in this implementation, which is fine since
       * it can't happen in JSP link management anyway.<p> 
       * 
       * @see org.opencms.util.I_CmsMacroResolver#resolveMacros(java.lang.String)
       */
      public String resolveMacros(String input) {
  
          // clear the list of links
          m_links.clear();
  
          // parse the input string
          String result;
  