org.apache.rocketmq.shaded.io.opentelemetry.api.internal.TemporaryBuffers Maven / Gradle / Ivy
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
package org.apache.rocketmq.shaded.io.opentelemetry.api.internal;
/**
* {@link ThreadLocal} buffers for use when creating new derived objects such as {@link String}s.
* These buffers are reused within a single thread - it is _not safe_ to use the buffer to generate
* multiple derived objects at the same time because the same memory will be used. In general, you
* should get a temporary buffer, fill it with data, and finish by converting into the derived
* object within the same method to avoid multiple usages of the same buffer.
*
* This class is internal and is hence not for public use. Its APIs are unstable and can change
* at any time.
*/
public final class TemporaryBuffers {
private static final ThreadLocal CHAR_ARRAY = new ThreadLocal<>();
/**
* A {@link ThreadLocal} {@code char[]} of size {@code len}. Take care when using a large value of
* {@code len} as this buffer will remain for the lifetime of the thread. The returned buffer will
* not be zeroed and may be larger than the requested size, you must make sure to fill the entire
* content to the desired value and set the length explicitly when converting to a {@link String}.
*/
public static char[] chars(int len) {
char[] buffer = CHAR_ARRAY.get();
if (buffer == null || buffer.length < len) {
buffer = new char[len];
CHAR_ARRAY.set(buffer);
}
return buffer;
}
// Visible for testing
static void clearChars() {
CHAR_ARRAY.set(null);
}
private TemporaryBuffers() {}
}