com.google.appengine.repackaged.com.google.common.flogger.parameter.BraceStyleParameter Maven / Gradle / Ivy
/*
* Copyright (C) 2012 The Flogger Authors.
*
* 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.google.common.flogger.parameter;
import com.google.common.flogger.backend.FormatChar;
import com.google.common.flogger.backend.FormatOptions;
import com.google.common.flogger.backend.FormatType;
import java.text.MessageFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
/**
* A parameter implementation to mimic the formatting of brace style placeholders (ie, "{n}").
*/
public class BraceStyleParameter extends Parameter {
// Format options to mimic how '{0}' is formatted for numbers (i.e. like "%,d" or "%,f").
private static final FormatOptions WITH_GROUPING =
FormatOptions.of(FormatOptions.FLAG_SHOW_GROUPING, FormatOptions.UNSET, FormatOptions.UNSET);
// Message formatter for fallback cases where '{n}' formats sufficiently differently to any
// available printf specifier that we must preformat the result ourselves.
// TODO: Get the Locale from the Platform class for better i18n support.
private static final MessageFormat prototypeMessageFormatter =
new MessageFormat("{0}", Locale.ROOT);
/** Cache parameters with indices 0-9 to cover the vast majority of cases. */
private static final int MAX_CACHED_PARAMETERS = 10;
/** Map of the most common default general parameters (corresponds to %s, %d, %f etc...). */
private static final BraceStyleParameter[] DEFAULT_PARAMETERS;
static {
DEFAULT_PARAMETERS = new BraceStyleParameter[MAX_CACHED_PARAMETERS];
for (int index = 0; index < MAX_CACHED_PARAMETERS; index++) {
DEFAULT_PARAMETERS[index] = new BraceStyleParameter(index);
}
}
/**
* Returns a {@link Parameter} representing a plain "brace style" placeholder "{n}". Note that a
* cached value may be returned.
*
* @param index the index of the argument to be processed.
* @return the immutable, thread safe parameter instance.
*/
public static BraceStyleParameter of(int index) {
return index < MAX_CACHED_PARAMETERS
? DEFAULT_PARAMETERS[index]
: new BraceStyleParameter(index);
}
private BraceStyleParameter(int index) {
super(FormatOptions.getDefault(), index);
}
@Override
protected void accept(ParameterVisitor visitor, Object value) {
// Special cases which MessageFormat treats specially (oddly Calendar is not a special case).
if (FormatType.INTEGRAL.canFormat(value)) {
visitor.visit(value, FormatChar.DECIMAL, WITH_GROUPING);
} else if (FormatType.FLOAT.canFormat(value)) {
// Technically floating point formatting via {0} differs from "%,f", but as "%,f" results in
// more precision it seems better to mimic "%,f" rather than discard both precision and type
// information by calling visitPreformatted().
visitor.visit(value, FormatChar.FLOAT, WITH_GROUPING);
} else if (value instanceof Date) {
// MessageFormat is not thread safe, so we always clone().
String formatted = ((MessageFormat) prototypeMessageFormatter.clone())
.format(new Object[] {value}, new StringBuffer(), null /* field position */)
.toString();
visitor.visitPreformatted(value, formatted);
} else if (value instanceof Calendar) {
visitor.visitDateTime(value, DateTimeFormat.DATETIME_FULL, getFormatOptions());
} else {
visitor.visit(value, FormatChar.STRING, getFormatOptions());
}
}
@Override
public String getFormat() {
return "%s";
}
}