PageIdentifier.java

/*
 * Copyright (C) 2011 Laurent Caillette
 *
 * This program 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 3 of the License, or (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.novelang.common.metadata;

import java.util.regex.Pattern;

import com.google.common.base.Preconditions;

/**
 * A page name for a multipage document.
 * The name is filesystem and URL friendly.
 *
 * @author Laurent Caillette
 */
public class PageIdentifier {

  private final String name ;

  public PageIdentifier( final String name ) {
    this.name = Preconditions.checkNotNull( name ) ;
    Preconditions.checkArgument(
        PATTERN.matcher( name ).matches(),
        "Name '%s' doesn't match %s",
        name,
        PATTERN.pattern()
    ) ;
  }

  /**
   * Returns a page identifier that will appear after originating document name in the URL.
   *
   * @return a non-null, possibly empty {@code String}.
   */
  public String getName() {
    return name;
  }

  /**
   * Identical to Tag syntax.
   */
  public static final Pattern PATTERN = Pattern.compile( "[a-zA-Z0-9]+(?:[_\\-][a-zA-Z0-9]+)*" ) ;

  @Override
  public boolean equals( final Object other ) {
    if( this == other ) {
      return true ;
    }
    if( other == null || getClass() != other.getClass() ) {
      return false ;
    }

    final PageIdentifier that = ( PageIdentifier ) other ;

    if( ! name.equals( that.name ) ) {
      return false ;
    }

    return true ;
  }

  @Override
  public int hashCode() {
    return name.hashCode() ;
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + "{" + name + "}" ;
  }
}