package evanq.game.trace; 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> * For example, * * <pre> * MessageFormatter.format("Hi {}.", "there") * </pre> * * 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, * * <pre> * MessageFormatter.format("Set {1,2,3} is not equal to {}.", "1,2"); * </pre> * * will return the string "Set {1,2,3} is not equal to 1,2.". * * <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, * * <pre> * MessageFormatter.format("Set \\{} is not equal to {}.", "1,2"); * </pre> * * will return the string "Set {} is not equal to 1,2.". * * <p> * The escaping behavior just described can be overridden by escaping the escape * character '\'. Calling * * <pre> * MessageFormatter.format("File name is C:\\\\{}.", "file.zip"); * </pre> * * will return the string "File name is C:\file.zip". * * <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> * See also {@link #format(String, Object)}, * {@link #format(String, Object, Object)} and * {@link #arrayFormat(String, Object[])} methods for more details. * * @author Ceki Gülcü * @author Joern Huxhorn */ @SuppressWarnings("rawtypes") 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, * * <pre> * MessageFormatter.format("Hi {}.", "there"); * </pre> * * will return the string "Hi there.". * <p> * * @param messagePattern * The message pattern which will be parsed and formatted * @param argument * The argument to be substituted in place of the formatting anchor * @return The formatted message */ final public 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, * * <pre> * MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob"); * </pre> * * will return the string "Hi Alice. My name is Bob.". * * @param messagePattern * The message pattern which will be parsed and formatted * @param arg1 * The argument to be substituted in place of the first formatting * anchor * @param arg2 * The argument to be substituted in place of the second formatting * anchor * @return The formatted message */ final public static FormattingTuple format(final String messagePattern, Object arg1, Object arg2) { return arrayFormat(messagePattern, new Object[] { arg1, arg2 }); } static final 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 */ final public 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()); i = j + 2; } } else { // normal case sbuf.append(messagePattern.substring(i, j)); deeplyAppendParameter(sbuf, argArray[L], new HashMap()); 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); } } final static boolean isEscapedDelimeter(String messagePattern, int delimeterStartIndex) { if (delimeterStartIndex == 0) { return false; } char potentialEscape = messagePattern.charAt(delimeterStartIndex - 1); if (potentialEscape == ESCAPE_CHAR) { return true; } else { return false; } } final static boolean isDoubleEscaped(String messagePattern, int delimeterStartIndex) { if (delimeterStartIndex >= 2 && messagePattern.charAt(delimeterStartIndex - 2) == ESCAPE_CHAR) { return true; } else { return false; } } // special treatment of array values was suggested by 'lizongbo' private static void deeplyAppendParameter(StringBuffer sbuf, Object o, Map 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()]"); } } @SuppressWarnings("unchecked") private static void objectArrayAppend(StringBuffer sbuf, Object[] a, Map 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(']'); } }