content: /* ========================================================================
   * JCommon : a free general purpose class library for the Java(tm) platform
   * ========================================================================
   *
   * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   * 
   * Project Info:  http://www.jfree.org/jcommon/index.html
   *
   * 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.
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
   * USA.  
   *
   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
   * in the United States and other countries.]
   * 
   * ------------------
   * AttributeList.java
   * ------------------
   * (C)opyright 2003-2005, by Thomas Morgner and Contributors.
   *
   * Original Author:  Thomas Morgner;
   * Contributor(s):   David Gilbert (for Object Refinery Limited);
   *
   * $Id: AttributeList.java,v 1.3 2005/10/18 13:35:06 mungady Exp $
   *
   * Changes
   * -------
   * 25-Sep-2003 : Initial version (TM);
   * 26-Nov-2003 : Javadoc updates (DG);
   *
   */
  
  package org.jfree.xml.writer;
  
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * The attribute list is used by a writer to specify the attributes
   * of an XML element in a certain order.
   *
   * @author Thomas Morgner
   */
  public class AttributeList {
  
      /**
       * A name/value pair of the attribute list.
       */
      private static class AttributeEntry {
          
          /** The name of the attribute entry. */
          private String name;
          
          /** The value of the attribute entry. */
          private String value;
  
          /**
           * Creates a new attribute entry for the given name and value.
           *
           * @param name  the attribute name (<code>null</code> not permitted).
           * @param value the attribute value (<code>null</code> not permitted).
           */
          public AttributeEntry(final String name, final String value) {
              if (name == null) {
                  throw new NullPointerException("Name must not be null. [" 
                                                 + name + ", " + value + "]");
              }
              if (value == null) {
                  throw new NullPointerException("Value must not be null. [" 
                                                 + name + ", " + value + "]");
              }
              this.name = name;
              this.value = value;
          }
  
          /**
           * Returns the attribute name.
           * 
           * @return the name.
           */
          public String getName() {
              return this.name;
          }
  
          /**
           * Returns the value of this attribute entry.
           * 
           * @return the value of the entry.
           */
          public String getValue() {
              return this.value;
          }
  
          /**
           * Checks whether the given object is an attribute entry with the same name.
           * 
           * @param o  the suspected other attribute entry.
           * 
           * @return <code>true</code> if the given object is equal, <code>false</code> otherwise.
           */
          public boolean equals(final Object o) {
              if (this == o) {
                  return true;
              }
              if (!(o instanceof AttributeEntry)) {
                  return false;
              }
  
              final AttributeEntry attributeEntry = (AttributeEntry) o;
              if (!this.name.equals(attributeEntry.name)) {
                  return false;
              }
              return true;
          }
  
          /**
           * Computes an hashcode for this entry.
           * 
           * @return the hashcode.
           */
          public int hashCode() {
              return this.name.hashCode();
          }
      }
  
      /**
       * An iterator over the attribute names of this list.
       */
      private static class AttributeIterator implements Iterator {
          
          /** The backend is an iterator over the attribute entries. */
          private Iterator backend;
  
          /**
           * Creates a new attribute iterator using the given iterator as backend.
           * 
           * @param backend  an iterator over the attribute entries (<code>null</code> not permitted).
           */
          public AttributeIterator(final Iterator backend) {
              if (backend == null) {
                  throw new NullPointerException();
              }
              this.backend = backend;
          }
  
          /**
           * Returns <tt>true</tt> if the iteration has more elements. (In other
           * words, returns <tt>true</tt> if <tt>next</tt> would return an element
           * rather than throwing an exception.)
           *
           * @return <tt>true</tt> if the iterator has more elements.
           */
          public boolean hasNext() {
              return this.backend.hasNext();
          }
  
          /**
           * Returns the next element in the iteration.
           *
           * @return the next element in the iteration.
           */
          public Object next() {
              final AttributeEntry entry = (AttributeEntry) this.backend.next();
              if (entry != null) {
                  return entry.getName();
              }
              return entry;
          }
  
          /**
           *
           * Removes from the underlying collection the last element returned by the
           * iterator (optional operation).  This method can be called only once per
           * call to <tt>next</tt>.  The behavior of an iterator is unspecified if
           * the underlying collection is modified while the iteration is in
           * progress in any way other than by calling this method.
           */
          public void remove() {
              this.backend.remove();
          }
      }
  
      /** The storage for all entries of this list. */
      private List entryList;
  
      /**
       * Creates an empty attribute list with no default values.
       */
      public AttributeList() {
          this.entryList = new java.util.ArrayList();
      }
  
      /**
       * Returns an iterator over all attribute names. The names are returned
       * in their oder of addition to the list. The iterator contains strings.
       *
       * @return the iterator over all attribute names.
       */
      public Iterator keys() {
          return new AttributeIterator(this.entryList.iterator());
      }
  
      /**
       * Defines an attribute.
       * 
       * @param name the name of the attribute to be defined
       * @param value the value of the attribute.
       */
      public synchronized void setAttribute(final String name, final String value) {
          final AttributeEntry entry = new AttributeEntry(name, value);
          final int pos = this.entryList.indexOf(entry);
          if (pos != -1) {
              this.entryList.remove(pos);
          }
          this.entryList.add(entry);
      }
  
      /**
       * Returns the attribute value for the given attribute name or null,
       * if the attribute is not defined in this list.
       *
       * @param name the name of the attribute
       * @return the attribute value or null.
       */
      public synchronized String getAttribute(final String name) {
          return getAttribute(name, null);
      }
  
      /**
       * Returns the attribute value for the given attribute name or the given
       * defaultvalue, if the attribute is not defined in this list.
       *
       * @param name the name of the attribute.
       * @param defaultValue  the default value.
       * 
       * @return the attribute value or the defaultValue.
       */
      public synchronized String getAttribute(final String name, final String defaultValue) {
          for (int i = 0; i < this.entryList.size(); i++) {
              final AttributeEntry ae = (AttributeEntry) this.entryList.get(i);
              if (ae.getName().equals(name)) {
                  return ae.getValue();
              }
          }
          return defaultValue;
      }
  
      /**
       * Removes the attribute with the given name from the list.
       *
       * @param name the name of the attribute which should be removed..
       */
      public synchronized void removeAttribute(final String name) {
          for (int i = 0; i < this.entryList.size(); i++) {
              final AttributeEntry ae = (AttributeEntry) this.entryList.get(i);
              if (ae.getName().equals(name)) {
                  this.entryList.remove(ae);
                  return;
              }
          }
      }
  }
  