AttributeAccessorSupport.java :  » J2EE » spring-ide_2.3.0 » org » springframework » core » Java Open Source

/*
 * Copyright 2002-2007 the original author or authors.
 *
 * 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.
 */

package org.springframework.core;

import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import org.springframework.util.Assert;

/**
 * Support class for {@link AttributeAccessor AttributeAccessors}, providing
 * a base implementation of all methods. To be extended by subclasses.
 *
 * <p>{@link Serializable} if subclasses and all attribute values are {@link Serializable}.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 2.0
 */
public abstract class AttributeAccessorSupport implements AttributeAccessor, Serializable {

  /** Map with String keys and Object values */
  private final Map attributes = new LinkedHashMap();


  public void setAttribute(String name, Object value) {
    Assert.notNull(name, "Name must not be null");
    if (value != null) {
      this.attributes.put(name, value);
    }
    else {
      removeAttribute(name);
    }
  }

  public Object getAttribute(String name) {
    Assert.notNull(name, "Name must not be null");
    return this.attributes.get(name);
  }

  public Object removeAttribute(String name) {
    Assert.notNull(name, "Name must not be null");
    return this.attributes.remove(name);
  }

  public boolean hasAttribute(String name) {
    Assert.notNull(name, "Name must not be null");
    return this.attributes.containsKey(name);
  }

  public String[] attributeNames() {
    Set attributeNames = this.attributes.keySet();
    return (String[]) attributeNames.toArray(new String[attributeNames.size()]);
  }


  /**
   * Copy the attributes from the supplied AttributeAccessor to this accessor.
   * @param source the AttributeAccessor to copy from
   */
  protected void copyAttributesFrom(AttributeAccessor source) {
    Assert.notNull(source, "Source must not be null");
    String[] attributeNames = source.attributeNames();
    for (int i = 0; i < attributeNames.length; i++) {
      String attributeName = attributeNames[i];
      setAttribute(attributeName, source.getAttribute(attributeName));
    }
  }


  public boolean equals(Object other) {
    if (this == other) {
      return true;
    }
    if (!(other instanceof AttributeAccessorSupport)) {
      return false;
    }
    AttributeAccessorSupport that = (AttributeAccessorSupport) other;
    return this.attributes.equals(that.attributes);
  }

  public int hashCode() {
    return this.attributes.hashCode();
  }

}