gt:     buf.append(") (children (");
context: /* PolicyNodeImpl.java -- An implementation of a policy tree node.
     Copyright (C) 2004  Free Software Foundation, Inc.
  
  This file is part of GNU Classpath.
  
  GNU Classpath is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2, or (at your option)
  any later version.
  
  GNU Classpath 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
  General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with GNU Classpath; see the file COPYING.  If not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  02111-1307 USA.
  
  Linking this library statically or dynamically with other modules is
  making a combined work based on this library.  Thus, the terms and
  conditions of the GNU General Public License cover the whole
  combination.
  
  As a special exception, the copyright holders of this library give you
  permission to link this library with independent modules to produce an
  executable, regardless of the license terms of these independent
  modules, and to copy and distribute the resulting executable under
  terms of your choice, provided that you also meet, for each linked
  independent module, the terms and conditions of the license of that
  module.  An independent module is a module which is not derived from
  or based on this library.  If you modify this library, you may extend
  this exception to your version of the library, but you are not
  obligated to do so.  If you do not wish to do so, delete this
  exception statement from your version. */
  
  
  package gnu.java.security.x509;
  
  import java.security.cert.PolicyNode;
  import java.security.cert.PolicyQualifierInfo;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  
  public final class PolicyNodeImpl implements PolicyNode
  {
  
    // Fields.
    // -------------------------------------------------------------------------
  
    private String policy;
    private final Set expectedPolicies;
    private final Set qualifiers;
    private final Set children;
    private PolicyNodeImpl parent;
    private int depth;
    private boolean critical;
    private boolean readOnly;
  
    // Constructors.
    // -------------------------------------------------------------------------
  
    public PolicyNodeImpl()
    {
      expectedPolicies = new HashSet();
      qualifiers = new HashSet();
      children = new HashSet();
      readOnly = false;
      critical = false;
    }
  
    // Instance methods.
    // -------------------------------------------------------------------------
  
    public void addChild(PolicyNodeImpl node)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      if (node.getParent() != null)
        throw new IllegalStateException("already a child node");
      node.parent = this;
      node.setDepth(depth + 1);
      children.add(node);
    }
  
    public Iterator getChildren()
    {
      return Collections.unmodifiableSet(children).iterator();
    }
  
    public int getDepth()
    {
      return depth;
    }
  
    public void setDepth(int depth)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      this.depth = depth;
    }
  
    public void addAllExpectedPolicies(Set policies)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      expectedPolicies.addAll(policies);
    }
  
    public void addExpectedPolicy(String policy)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      expectedPolicies.add(policy);
    }
  
    public Set getExpectedPolicies()
    {
      return Collections.unmodifiableSet(expectedPolicies);
    }
  
    public PolicyNode getParent()
    {
      return parent;
    }
  
    public void addAllPolicyQualifiers (Collection qualifiers)
    {
      for (Iterator it = qualifiers.iterator(); it.hasNext(); )
        {
          if (!(it.next() instanceof PolicyQualifierInfo))
            throw new IllegalArgumentException ("can only add PolicyQualifierInfos");
        }
      qualifiers.addAll (qualifiers);
    }
  
    public void addPolicyQualifier (PolicyQualifierInfo qualifier)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      qualifiers.add(qualifier);
    }
  
    public Set getPolicyQualifiers()
    {
      return Collections.unmodifiableSet(qualifiers);
    }
  
    public String getValidPolicy()
    {
      return policy;
    }
  
    public void setValidPolicy(String policy)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      this.policy = policy;
    }
  
    public boolean isCritical()
    {
      return critical;
    }
  
    public void setCritical(boolean critical)
    {
      if (readOnly)
        throw new IllegalStateException("read only");
      this.critical = critical;
    }
  
    public void setReadOnly()
    {
      if (readOnly)
        return;
      readOnly = true;
      for (Iterator it = getChildren(); it.hasNext(); )
        ((PolicyNodeImpl) it.next()).setReadOnly();
    }
  
    public String toString()
    {
      StringBuffer buf = new StringBuffer();
      for (int i = 0; i < depth; i++)
        buf.append("  ");
      buf.append("(");
      buf.append(PolicyNodeImpl.class.getName());
      buf.append(" (oid ");
      buf.append(policy);
      buf.append(") (depth ");
      buf.append(depth);
      buf.append(") (qualifiers ");
      buf.append(qualifiers);
      buf.append(") (critical ");
      buf.append(critical);
      buf.append(") (expectedPolicies ");
      buf.append(expectedPolicies);
  