| /******************************************************************************* |
| * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Brock Janiczak - analysis and concept |
| * Marc R. Hoffmann - initial API and implementation |
| * |
| *******************************************************************************/ |
| package org.jacoco.core.internal.analysis; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Utility to normalize {@link String} instances in a way that if |
| * <code>equals()</code> is <code>true</code> for two strings they will be |
| * represented the same instance. While this is exactly what |
| * {@link String#intern()} does, this implementation avoids VM specific side |
| * effects and is supposed to be faster, as neither native code is called nor |
| * synchronization is required for concurrent lookup. |
| */ |
| public final class StringPool { |
| |
| private static final String[] EMPTY_ARRAY = new String[0]; |
| |
| private final Map<String, String> pool = new HashMap<String, String>(1024); |
| |
| /** |
| * Returns a normalized instance that is equal to the given {@link String} . |
| * |
| * @param s |
| * any string or <code>null</code> |
| * @return normalized instance or <code>null</code> |
| */ |
| public String get(final String s) { |
| if (s == null) { |
| return null; |
| } |
| final String norm = pool.get(s); |
| if (norm == null) { |
| pool.put(s, s); |
| return s; |
| } |
| return norm; |
| } |
| |
| /** |
| * Returns a modified version of the array with all string slots normalized. |
| * It is up to the implementation to replace strings in the array instance |
| * or return a new array instance. |
| * |
| * @param arr |
| * String array or <code>null</code> |
| * @return normalized instance or <code>null</code> |
| */ |
| public String[] get(final String[] arr) { |
| if (arr == null) { |
| return null; |
| } |
| if (arr.length == 0) { |
| return EMPTY_ARRAY; |
| } |
| for (int i = 0; i < arr.length; i++) { |
| arr[i] = get(arr[i]); |
| } |
| return arr; |
| } |
| |
| } |