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/*
 * Copyright 2018 mayabot.com authors. All rights reserved.
 *
 * 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.mayabot.nlp.common.logging;

import java.text.MessageFormat;
import java.util.HashSet;
import java.util.Set;

// contributors: lizongbo: proposed special treatment of array parameter values
// Joern Huxhorn: pointed out double[] omission, suggested deep array copy

/**
 * Formats messages according to very simple substitution rules. Substitutions
 * can be made 1, 2 or more arguments.
 * 

*

* For example, *

*

 * MessageFormatter.format("Hi {}.", "there")
 * 
*

* will return the string "Hi there.". *

* The {} pair is called the formatting anchor. It serves to designate * the location where arguments need to be substituted within the message * pattern. *

* In case your message contains the '{' or the '}' character, you do not have * to do anything special unless the '}' character immediately follows '{'. For * example, *

*

 * MessageFormatter.format("Set {1,2,3} is not equal to {}.", "1,2");
 * 
*

* will return the string "Set {1,2,3} is not equal to 1,2.". *

*

* If for whatever reason you need to place the string "{}" in the message * without its formatting anchor meaning, then you need to escape the * '{' character with '\', that is the backslash character. Only the '{' * character should be escaped. There is no need to escape the '}' character. * For example, *

*

 * MessageFormatter.format("Set \\{} is not equal to {}.", "1,2");
 * 
*

* will return the string "Set {} is not equal to 1,2.". *

*

* The escaping behavior just described can be overridden by escaping the escape * character '\'. Calling *

*

 * MessageFormatter.format("File name is C:\\\\{}.", "file.zip");
 * 
*

* will return the string "File name is C:\file.zip". *

*

* The formatting conventions are different than those of {@link MessageFormat} * which ships with the Java platform. This is justified by the fact that * SLF4J's implementation is 10 times faster than that of {@link MessageFormat}. * This local performance difference is both measurable and significant in the * larger context of the complete logging processing chain. *

*

* See also {@link #format(String, Object)}, * {@link #format(String, Object, Object)} and * {@link #arrayFormat(String, Object[])} methods for more details. */ final class MessageFormatter { private static final String DELIM_STR = "{}"; private static final char ESCAPE_CHAR = '\\'; /** * Performs single argument substitution for the 'messagePattern' passed as * parameter. *

* For example, *

*

     * MessageFormatter.format("Hi {}.", "there");
     * 
*

* will return the string "Hi there.". *

* * @param messagePattern The message pattern which will be parsed and formatted * @param arg The argument to be substituted in place of the formatting anchor * @return The formatted message */ static FormattingTuple format(String messagePattern, Object arg) { return arrayFormat(messagePattern, new Object[]{arg}); } /** * Performs a two argument substitution for the 'messagePattern' passed as * parameter. *

* For example, *

*

     * MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob");
     * 
*

* will return the string "Hi Alice. My name is Bob.". * * @param messagePattern The message pattern which will be parsed and formatted * @param argA The argument to be substituted in place of the first formatting * anchor * @param argB The argument to be substituted in place of the second formatting * anchor * @return The formatted message */ static FormattingTuple format(final String messagePattern, Object argA, Object argB) { return arrayFormat(messagePattern, new Object[]{argA, argB}); } /** * Same principle as the {@link #format(String, Object)} and * {@link #format(String, Object, Object)} methods except that any number of * arguments can be passed in an array. * * @param messagePattern The message pattern which will be parsed and formatted * @param argArray An array of arguments to be substituted in place of formatting * anchors * @return The formatted message */ static FormattingTuple arrayFormat(final String messagePattern, final Object[] argArray) { if (argArray == null || argArray.length == 0) { return new FormattingTuple(messagePattern, null); } int lastArrIdx = argArray.length - 1; Object lastEntry = argArray[lastArrIdx]; Throwable throwable = lastEntry instanceof Throwable ? (Throwable) lastEntry : null; if (messagePattern == null) { return new FormattingTuple(null, throwable); } int j = messagePattern.indexOf(DELIM_STR); if (j == -1) { // this is a simple string return new FormattingTuple(messagePattern, throwable); } StringBuilder sbuf = new StringBuilder(messagePattern.length() + 50); int i = 0; int L = 0; do { boolean notEscaped = j == 0 || messagePattern.charAt(j - 1) != ESCAPE_CHAR; if (notEscaped) { // normal case sbuf.append(messagePattern, i, j); } else { sbuf.append(messagePattern, i, j - 1); // check that escape char is not is escaped: "abc x:\\{}" notEscaped = j >= 2 && messagePattern.charAt(j - 2) == ESCAPE_CHAR; } i = j + 2; if (notEscaped) { deeplyAppendParameter(sbuf, argArray[L], null); L++; if (L > lastArrIdx) { break; } } else { sbuf.append(DELIM_STR); } j = messagePattern.indexOf(DELIM_STR, i); } while (j != -1); // append the characters following the last {} pair. sbuf.append(messagePattern, i, messagePattern.length()); return new FormattingTuple(sbuf.toString(), L <= lastArrIdx ? throwable : null); } // special treatment of array values was suggested by 'lizongbo' private static void deeplyAppendParameter(StringBuilder sbuf, Object o, Set seenSet) { if (o == null) { sbuf.append("null"); return; } Class objClass = o.getClass(); if (!objClass.isArray()) { if (Number.class.isAssignableFrom(objClass)) { // Prevent String instantiation for some number types if (objClass == Long.class) { sbuf.append(((Long) o).longValue()); } else if (objClass == Integer.class || objClass == Short.class || objClass == Byte.class) { sbuf.append(((Number) o).intValue()); } else if (objClass == Double.class) { sbuf.append(((Double) o).doubleValue()); } else if (objClass == Float.class) { sbuf.append(((Float) o).floatValue()); } else { safeObjectAppend(sbuf, o); } } else { safeObjectAppend(sbuf, o); } } else { // check for primitive array types because they // unfortunately cannot be cast to Object[] sbuf.append('['); if (objClass == boolean[].class) { booleanArrayAppend(sbuf, (boolean[]) o); } else if (objClass == byte[].class) { byteArrayAppend(sbuf, (byte[]) o); } else if (objClass == char[].class) { charArrayAppend(sbuf, (char[]) o); } else if (objClass == short[].class) { shortArrayAppend(sbuf, (short[]) o); } else if (objClass == int[].class) { intArrayAppend(sbuf, (int[]) o); } else if (objClass == long[].class) { longArrayAppend(sbuf, (long[]) o); } else if (objClass == float[].class) { floatArrayAppend(sbuf, (float[]) o); } else if (objClass == double[].class) { doubleArrayAppend(sbuf, (double[]) o); } else { objectArrayAppend(sbuf, (Object[]) o, seenSet); } sbuf.append(']'); } } private static void safeObjectAppend(StringBuilder sbuf, Object o) { try { String oAsString = o.toString(); sbuf.append(oAsString); } catch (Throwable t) { System.err .println("SLF4J: Failed toString() invocation on an object of type [" + o.getClass().getName() + ']'); t.printStackTrace(); sbuf.append("[FAILED toString()]"); } } private static void objectArrayAppend(StringBuilder sbuf, Object[] a, Set seenSet) { if (a.length == 0) { return; } if (seenSet == null) { seenSet = new HashSet(a.length); } if (seenSet.add(a)) { deeplyAppendParameter(sbuf, a[0], seenSet); for (int i = 1; i < a.length; i++) { sbuf.append(", "); deeplyAppendParameter(sbuf, a[i], seenSet); } // allow repeats in siblings seenSet.remove(a); } else { sbuf.append("..."); } } private static void booleanArrayAppend(StringBuilder sbuf, boolean[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void byteArrayAppend(StringBuilder sbuf, byte[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void charArrayAppend(StringBuilder sbuf, char[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void shortArrayAppend(StringBuilder sbuf, short[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void intArrayAppend(StringBuilder sbuf, int[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void longArrayAppend(StringBuilder sbuf, long[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void floatArrayAppend(StringBuilder sbuf, float[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private static void doubleArrayAppend(StringBuilder sbuf, double[] a) { if (a.length == 0) { return; } sbuf.append(a[0]); for (int i = 1; i < a.length; i++) { sbuf.append(", "); sbuf.append(a[i]); } } private MessageFormatter() { } }





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