GrantedAuthorityToString.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program 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.
 *
 * Copyright 2007 - 2009 Pentaho Corporation.  All rights reserved.
 *
 */
package org.pentaho.platform.plugin.services.security.userrole.ldap.transform;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.apache.commons.collections.Transformer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.platform.plugin.services.messages.Messages;
import org.springframework.security.GrantedAuthority;
import org.springframework.util.Assert;

/**
 * Transforms a <code>GrantedAuthority</code> into a <code>String</code>.
 * Can handle either a single <code>GrantedAuthority</code> or a collection
 * (or array) of <code>GrantedAuthority</code> instances. Always returns a
 * collection or array if collection or array was the input.
 * 
 * <p>
 * Transformer input: <code>GrantedAuthority</code> instance,
 * <code>Collection</code> of <code>GrantedAuthority</code> instances, or
 * array of <code>GrantedAuthority</code> instances.
 * </p>
 * <p>
 * Transformer output: <code>String</code> instance, <code>Collection</code>
 * of <code>String</code> instances, or array of <code>String</code>
 * instances.
 * </p>
 * 
 * @author mlowery
 */
public class GrantedAuthorityToString implements Transformer {
  // ~ Static fields/initializers ============================================

  private static final Log logger = LogFactory.getLog(GrantedAuthorityToString.class);

  // ~ Instance fields =======================================================

  private String rolePrefix = "ROLE_"; //$NON-NLS-1$

  // ~ Constructors ==========================================================

  public GrantedAuthorityToString() {
    super();
  }

  // ~ Methods ===============================================================

  public Object transform(final Object obj) {
    if (GrantedAuthorityToString.logger.isDebugEnabled()) {
      String input = (obj instanceof Object[] ? Arrays.asList((Object[]) obj).toString() : obj.toString());
      GrantedAuthorityToString.logger.debug(Messages.getInstance().getString("GrantedAuthorityToString.DEBUG_INPUT_TO_TRANSFORM", //$NON-NLS-1$
          input));
    }

    Object transformed = obj;
    if (obj instanceof GrantedAuthority) {
      transformed = transformItem(obj);
    } else if (obj instanceof Collection) {
      transformed = new HashSet();
      Set authSet = (Set) transformed;
      Iterator iter = ((Collection) obj).iterator();
      while (iter.hasNext()) {
        authSet.add(transformItem(iter.next()));
      }
    } else if (obj instanceof Object[]) {
      transformed = new HashSet();
      Set authSet = (Set) transformed;
      Object[] objArray = (Object[]) obj;
      for (Object element : objArray) {
        authSet.add(transformItem(element));
      }
      transformed = authSet.toArray();
    }
    return transformed;
  }

  protected Object transformItem(final Object obj) {
    Object transformed = obj;
    if (obj instanceof GrantedAuthority) {
      String auth = ((GrantedAuthority) obj).getAuthority();
      if (auth.startsWith(rolePrefix)) {
        auth = auth.substring(rolePrefix.length());
      }
      transformed = auth;
    }
    return transformed;
  }

  public void setRolePrefix(final String rolePrefix) {
    Assert.hasLength(rolePrefix);
    this.rolePrefix = rolePrefix;
  }

}