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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 zipkin2.internal;

import java.io.IOException;
import org.jvnet.animal_sniffer.IgnoreJRERequirement;

/**
 * Provides access to platform-specific features.
 *
 * Originally designed by OkHttp team, derived from {@code okhttp3.internal.platform.Platform}
 */
public abstract class Platform {
  private static final Platform PLATFORM = findPlatform();

  Platform() {
  }

  static final ThreadLocal SHORT_STRING_BUFFER = new ThreadLocal<>();
  /** Maximum character length constraint of most names, IP literals and IDs. */
  public static final int SHORT_STRING_LENGTH = 256;

  /**
   * Returns a {@link ThreadLocal} reused {@code char[]} for use when decoding bytes into hex, IP
   * literals, or {@link #SHORT_STRING_LENGTH short strings}. The buffer must never be leaked
   * outside the method. Most will {@link String#String(char[], int, int) copy it into a string}.
   */
  public static char[] shortStringBuffer() {
    char[] shortStringBuffer = SHORT_STRING_BUFFER.get();
    if (shortStringBuffer == null) {
      shortStringBuffer = new char[SHORT_STRING_LENGTH];
      SHORT_STRING_BUFFER.set(shortStringBuffer);
    }
    return shortStringBuffer;
  }

  public RuntimeException uncheckedIOException(IOException e) {
    return new RuntimeException(e);
  }

  public AssertionError assertionError(String message, Throwable cause) {
    AssertionError error = new AssertionError(message);
    error.initCause(cause);
    throw error;
  }

  public static Platform get() {
    return PLATFORM;
  }

  /** Attempt to match the host runtime to a capable Platform implementation. */
  static Platform findPlatform() {
    Platform jre8 = Jre8.buildIfSupported();

    if (jre8 != null) return jre8;

    Platform jre7 = Jre7.buildIfSupported();

    if (jre7 != null) return jre7;

    // compatible with JRE 6
    return Jre6.build();
  }

  static final class Jre8 extends Jre7 {
    static Jre8 buildIfSupported() {
      // Find JRE 8 new types
      try {
        Class.forName("java.io.UncheckedIOException");
        return new Jre8();
      } catch (ClassNotFoundException e) {
        // pre JRE 8
      }
      return null;
    }

    @IgnoreJRERequirement @Override public RuntimeException uncheckedIOException(IOException e) {
      return new java.io.UncheckedIOException(e);
    }
  }

  static class Jre7 extends Platform {
    static Jre7 buildIfSupported() {
      // Find JRE 7 new types
      try {
        Class.forName("java.util.concurrent.ThreadLocalRandom");
        return new Jre7();
      } catch (ClassNotFoundException e) {
        // pre JRE 7
      }
      return null;
    }

    @IgnoreJRERequirement @Override
    public AssertionError assertionError(String message, Throwable cause) {
      return new AssertionError(message, cause);
    }
  }

  static final class Jre6 extends Platform {
    static Jre6 build() {
      return new Jre6();
    }
  }
}