PropertySupport.java

/*
 * Created on Jun 26, 2010
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 *
 * Copyright @2010-2011 the original author or authors.
 */
package org.fest.assertions.internal;

import org.fest.util.VisibleForTesting;

/**
 * Utility methods for properties access.
 *
 * @author Joel Costigliola
 * @author Alex Ruiz
 */
public class PropertySupport {

  private static final String SEPARATOR = ".";

  private static final PropertySupport INSTANCE = new PropertySupport();

  /**
   * Returns the singleton instance of this class.
   * @return the singleton instance of this class.
   */
  public static PropertySupport instance() {
    return INSTANCE;
  }

  @VisibleForTesting PropertySupport() {}

  private String popPropertyNameFrom(String propertyNameChain) {
    if (!isNestedProperty(propertyNameChain)) return propertyNameChain;
    return propertyNameChain.substring(0, propertyNameChain.indexOf(SEPARATOR));
  }

  private String nextPropertyNameFrom(String propertyNameChain) {
    if (!isNestedProperty(propertyNameChain)) return "";
    return propertyNameChain.substring(propertyNameChain.indexOf(SEPARATOR) + 1);
  }

  /*
   * isNestedProperty("address.street");       // true
   * isNestedProperty("address.street.name");  // true
   * isNestedProperty("person");               // false
   * isNestedProperty(".name");                // false
   * isNestedProperty("person.");              // false
   * isNestedProperty("person.name.");         // false
   * isNestedProperty(".person.name");         // false
   * isNestedProperty(".");                    // false
   * isNestedProperty("");                     // false
   */
  private boolean isNestedProperty(String propertyName) {
    return propertyName.contains(SEPARATOR) && !propertyName.startsWith(SEPARATOR) && !propertyName.endsWith(SEPARATOR);
  }
}