MessageFormatter.java
/*
* Copyright 2013 The Netty Project
*
* The Netty Project 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.
*/
/**
* Copyright (c) 2004-2011 QOS.ch
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
package com.foxinmy.weixin4j.logging;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;
// 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.
* <p/>
* <p/>
* For example,
* <p/>
* <pre>
* MessageFormatter.format("Hi {}.", "there")
* </pre>
* <p/>
* will return the string "Hi there.".
* <p/>
* The {} pair is called the <em>formatting anchor</em>. It serves to designate
* the location where arguments need to be substituted within the message
* pattern.
* <p/>
* In case your message contains the '{' or the '}' character, you do not have
* to do anything special unless the '}' character immediately follows '{'. For
* example,
* <p/>
* <pre>
* MessageFormatter.format("Set {1,2,3} is not equal to {}.", "1,2");
* </pre>
* <p/>
* will return the string "Set {1,2,3} is not equal to 1,2.".
* <p/>
* <p/>
* If for whatever reason you need to place the string "{}" in the message
* without its <em>formatting anchor</em> 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,
* <p/>
* <pre>
* MessageFormatter.format("Set \\{} is not equal to {}.", "1,2");
* </pre>
* <p/>
* will return the string "Set {} is not equal to 1,2.".
* <p/>
* <p/>
* The escaping behavior just described can be overridden by escaping the escape
* character '\'. Calling
* <p/>
* <pre>
* MessageFormatter.format("File name is C:\\\\{}.", "file.zip");
* </pre>
* <p/>
* will return the string "File name is C:\file.zip".
* <p/>
* <p/>
* 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.
* <p/>
* <p/>
* See also {@link #format(String, Object)},
* {@link #format(String, Object, Object)} and
* {@link #arrayFormat(String, Object[])} methods for more details.
*/
final class MessageFormatter {
static final char DELIM_START = '{';
static final char DELIM_STOP = '}';
static final String DELIM_STR = "{}";
private static final char ESCAPE_CHAR = '\\';
/**
* Performs single argument substitution for the 'messagePattern' passed as
* parameter.
* <p/>
* For example,
* <p/>
* <pre>
* MessageFormatter.format("Hi {}.", "there");
* </pre>
* <p/>
* will return the string "Hi there.".
* <p/>
*
* @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.
* <p/>
* For example,
* <p/>
* <pre>
* MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob");
* </pre>
* <p/>
* 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});
}
static Throwable getThrowableCandidate(Object[] argArray) {
if (argArray == null || argArray.length == 0) {
return null;
}
final Object lastEntry = argArray[argArray.length - 1];
if (lastEntry instanceof Throwable) {
return (Throwable) lastEntry;
}
return null;
}
/**
* 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) {
Throwable throwableCandidate = getThrowableCandidate(argArray);
if (messagePattern == null) {
return new FormattingTuple(null, argArray, throwableCandidate);
}
if (argArray == null) {
return new FormattingTuple(messagePattern);
}
int i = 0;
int j;
StringBuffer sbuf = new StringBuffer(messagePattern.length() + 50);
int L;
for (L = 0; L < argArray.length; L++) {
j = messagePattern.indexOf(DELIM_STR, i);
if (j == -1) {
// no more variables
if (i == 0) { // this is a simple string
return new FormattingTuple(messagePattern, argArray,
throwableCandidate);
} else { // add the tail string which contains no variables and return
// the result.
sbuf.append(messagePattern.substring(i, messagePattern.length()));
return new FormattingTuple(sbuf.toString(), argArray,
throwableCandidate);
}
} else {
if (isEscapedDelimeter(messagePattern, j)) {
if (!isDoubleEscaped(messagePattern, j)) {
L--; // DELIM_START was escaped, thus should not be incremented
sbuf.append(messagePattern.substring(i, j - 1));
sbuf.append(DELIM_START);
i = j + 1;
} else {
// The escape character preceding the delimiter start is
// itself escaped: "abc x:\\{}"
// we have to consume one backward slash
sbuf.append(messagePattern.substring(i, j - 1));
deeplyAppendParameter(sbuf, argArray[L], new HashMap<Object[], Void>());
i = j + 2;
}
} else {
// normal case
sbuf.append(messagePattern.substring(i, j));
deeplyAppendParameter(sbuf, argArray[L], new HashMap<Object[], Void>());
i = j + 2;
}
}
}
// append the characters following the last {} pair.
sbuf.append(messagePattern.substring(i, messagePattern.length()));
if (L < argArray.length - 1) {
return new FormattingTuple(sbuf.toString(), argArray, throwableCandidate);
} else {
return new FormattingTuple(sbuf.toString(), argArray, null);
}
}
static boolean isEscapedDelimeter(String messagePattern,
int delimeterStartIndex) {
if (delimeterStartIndex == 0) {
return false;
}
return messagePattern.charAt(delimeterStartIndex - 1) == ESCAPE_CHAR;
}
static boolean isDoubleEscaped(String messagePattern,
int delimeterStartIndex) {
return delimeterStartIndex >= 2 && messagePattern.charAt(delimeterStartIndex - 2) == ESCAPE_CHAR;
}
// special treatment of array values was suggested by 'lizongbo'
private static void deeplyAppendParameter(StringBuffer sbuf, Object o,
Map<Object[], Void> seenMap) {
if (o == null) {
sbuf.append("null");
return;
}
if (!o.getClass().isArray()) {
safeObjectAppend(sbuf, o);
} else {
// check for primitive array types because they
// unfortunately cannot be cast to Object[]
if (o instanceof boolean[]) {
booleanArrayAppend(sbuf, (boolean[]) o);
} else if (o instanceof byte[]) {
byteArrayAppend(sbuf, (byte[]) o);
} else if (o instanceof char[]) {
charArrayAppend(sbuf, (char[]) o);
} else if (o instanceof short[]) {
shortArrayAppend(sbuf, (short[]) o);
} else if (o instanceof int[]) {
intArrayAppend(sbuf, (int[]) o);
} else if (o instanceof long[]) {
longArrayAppend(sbuf, (long[]) o);
} else if (o instanceof float[]) {
floatArrayAppend(sbuf, (float[]) o);
} else if (o instanceof double[]) {
doubleArrayAppend(sbuf, (double[]) o);
} else {
objectArrayAppend(sbuf, (Object[]) o, seenMap);
}
}
}
private static void safeObjectAppend(StringBuffer 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(StringBuffer sbuf, Object[] a,
Map<Object[], Void> seenMap) {
sbuf.append('[');
if (!seenMap.containsKey(a)) {
seenMap.put(a, null);
final int len = a.length;
for (int i = 0; i < len; i++) {
deeplyAppendParameter(sbuf, a[i], seenMap);
if (i != len - 1) {
sbuf.append(", ");
}
}
// allow repeats in siblings
seenMap.remove(a);
} else {
sbuf.append("...");
}
sbuf.append(']');
}
private static void booleanArrayAppend(StringBuffer sbuf, boolean[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void byteArrayAppend(StringBuffer sbuf, byte[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void charArrayAppend(StringBuffer sbuf, char[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void shortArrayAppend(StringBuffer sbuf, short[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void intArrayAppend(StringBuffer sbuf, int[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void longArrayAppend(StringBuffer sbuf, long[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void floatArrayAppend(StringBuffer sbuf, float[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private static void doubleArrayAppend(StringBuffer sbuf, double[] a) {
sbuf.append('[');
final int len = a.length;
for (int i = 0; i < len; i++) {
sbuf.append(a[i]);
if (i != len - 1) {
sbuf.append(", ");
}
}
sbuf.append(']');
}
private MessageFormatter() {
}
}