src/com/google/inject/util/ToStringBuilder.java

/**
 * Copyright (C) 2006 Google Inc.
 *
 * 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 com.google.inject.util;

import java.util.Map;
import java.util.LinkedHashMap;

/**
 * Helps with {@code toString()} methods.
 *
 * @author crazybob@google.com (Bob Lee)
 */
public class ToStringBuilder {

  // Linked hash map ensures ordering.
  final Map<String, Object> map = new LinkedHashMap<String, Object>();

  final String name;

  public ToStringBuilder(String name) {
    this.name = name;
  }

  public ToStringBuilder(Class type) {
    this.name = type.getSimpleName();
  }

  public ToStringBuilder add(String name, Object value) {
    if (map.put(name, value) != null) {
      throw new RuntimeException("Duplicate names: " + name);
    }
    return this;
  }

  public String toString() {
    return name + map.toString();
  }
}