com.google.instrumentation.stats.TagKey Maven / Gradle / Ivy

/*
 * Copyright 2016, 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.instrumentation.stats;

import com.google.auto.value.AutoValue;

/**
 * Tag keys.
 *
 * TagKey's are {@link String}s with enforced restrictions.
 */
@AutoValue
public abstract class TagKey {
  public static final int MAX_LENGTH = StringUtil.MAX_LENGTH;

  TagKey() {}

  /**
   * Constructs a new {@link TagKey} from the given string. The string will be sanitize such that:
   * 

   * length is restricted to {@link MAX_LENGTH}, strings longer than that will be truncated.
   * 
characters are restricted to printable ascii characters, non-printable characters will be
   * replaced by an underscore '_'.
   * 
   */
  public static TagKey create(String key) {
    return new AutoValue_TagKey(StringUtil.sanitize(key));
  }

  public abstract String asString();

  // TODO(sebright) Use the default AutoValue toString(), which is more useful for debugging.
  // gRPC is currently calling toString() to access the key field, so we can't change it yet.
  @Override
  public final String toString() {
    return asString();
  }
}