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Apache Commons Text is a library focused on algorithms working on strings.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
package org.apache.commons.text;
import java.text.Format;
import java.text.MessageFormat;
import java.text.ParsePosition;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Locale;
import java.util.Locale.Category;
import java.util.Map;
import java.util.Objects;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.text.matcher.StringMatcherFactory;
/**
* Extends {@code java.text.MessageFormat} to allow pluggable/additional formatting
* options for embedded format elements. Client code should specify a registry
* of {@code FormatFactory} instances associated with {@code String}
* format names. This registry will be consulted when the format elements are
* parsed from the message pattern. In this way custom patterns can be specified,
* and the formats supported by {@code java.text.MessageFormat} can be overridden
* at the format and/or format style level (see MessageFormat). A "format element"
* embedded in the message pattern is specified (()? signifies optionality):
* {@code {}argument-number({@code ,}format-name
* ({@code ,}format-style)?)?{@code }}
*
*
* format-name and format-style values are trimmed of surrounding whitespace
* in the manner of {@code java.text.MessageFormat}. If format-name denotes
* {@code FormatFactory formatFactoryInstance} in {@code registry}, a {@code Format}
* matching format-name and format-style is requested from
* {@code formatFactoryInstance}. If this is successful, the {@code Format}
* found is used for this format element.
*
*
* NOTICE: The various subformat mutator methods are considered unnecessary; they exist on the parent
* class to allow the type of customization which it is the job of this class to provide in
* a configurable fashion. These methods have thus been disabled and will throw
* {@code UnsupportedOperationException} if called.
*
*
* Limitations inherited from {@code java.text.MessageFormat}:
*
* - When using "choice" subformats, support for nested formatting instructions is limited
* to that provided by the base class.
* - Thread-safety of {@code Format}s, including {@code MessageFormat} and thus
* {@code ExtendedMessageFormat}, is not guaranteed.
*
*
* @since 1.0
*/
public class ExtendedMessageFormat extends MessageFormat {
/**
* Serializable Object.
*/
private static final long serialVersionUID = -2362048321261811743L;
/**
* Our initial seed value for calculating hashes.
*/
private static final int HASH_SEED = 31;
/**
* The empty string.
*/
private static final String DUMMY_PATTERN = StringUtils.EMPTY;
/**
* A comma.
*/
private static final char START_FMT = ',';
/**
* A right side squiggly brace.
*/
private static final char END_FE = '}';
/**
* A left side squiggly brace.
*/
private static final char START_FE = '{';
/**
* A properly escaped character representing a single quote.
*/
private static final char QUOTE = '\'';
/**
* To pattern string.
*/
private String toPattern;
/**
* Our registry of FormatFactory's.
*/
private final Map registry;
/**
* Create a new ExtendedMessageFormat for the default locale.
*
* @param pattern the pattern to use, not null
* @throws IllegalArgumentException in case of a bad pattern.
*/
public ExtendedMessageFormat(final String pattern) {
this(pattern, Locale.getDefault(Category.FORMAT));
}
/**
* Create a new ExtendedMessageFormat.
*
* @param pattern the pattern to use, not null
* @param locale the locale to use, not null
* @throws IllegalArgumentException in case of a bad pattern.
*/
public ExtendedMessageFormat(final String pattern, final Locale locale) {
this(pattern, locale, null);
}
/**
* Create a new ExtendedMessageFormat for the default locale.
*
* @param pattern the pattern to use, not null
* @param registry the registry of format factories, may be null
* @throws IllegalArgumentException in case of a bad pattern.
*/
public ExtendedMessageFormat(final String pattern,
final Map registry) {
this(pattern, Locale.getDefault(Category.FORMAT), registry);
}
/**
* Create a new ExtendedMessageFormat.
*
* @param pattern the pattern to use, not null
* @param locale the locale to use, not null
* @param registry the registry of format factories, may be null
* @throws IllegalArgumentException in case of a bad pattern.
*/
public ExtendedMessageFormat(final String pattern,
final Locale locale,
final Map registry) {
super(DUMMY_PATTERN);
setLocale(locale);
this.registry = registry;
applyPattern(pattern);
}
/**
* {@inheritDoc}
*/
@Override
public String toPattern() {
return toPattern;
}
/**
* Apply the specified pattern.
*
* @param pattern String
*/
@Override
public final void applyPattern(final String pattern) {
if (registry == null) {
super.applyPattern(pattern);
toPattern = super.toPattern();
return;
}
final ArrayList foundFormats = new ArrayList<>();
final ArrayList foundDescriptions = new ArrayList<>();
final StringBuilder stripCustom = new StringBuilder(pattern.length());
final ParsePosition pos = new ParsePosition(0);
final char[] c = pattern.toCharArray();
int fmtCount = 0;
while (pos.getIndex() < pattern.length()) {
switch (c[pos.getIndex()]) {
case QUOTE:
appendQuotedString(pattern, pos, stripCustom);
break;
case START_FE:
fmtCount++;
seekNonWs(pattern, pos);
final int start = pos.getIndex();
final int index = readArgumentIndex(pattern, next(pos));
stripCustom.append(START_FE).append(index);
seekNonWs(pattern, pos);
Format format = null;
String formatDescription = null;
if (c[pos.getIndex()] == START_FMT) {
formatDescription = parseFormatDescription(pattern,
next(pos));
format = getFormat(formatDescription);
if (format == null) {
stripCustom.append(START_FMT).append(formatDescription);
}
}
foundFormats.add(format);
foundDescriptions.add(format == null ? null : formatDescription);
if (foundFormats.size() != fmtCount) {
throw new IllegalArgumentException("The validated expression is false");
}
if (foundDescriptions.size() != fmtCount) {
throw new IllegalArgumentException("The validated expression is false");
}
if (c[pos.getIndex()] != END_FE) {
throw new IllegalArgumentException(
"Unreadable format element at position " + start);
}
//$FALL-THROUGH$
default:
stripCustom.append(c[pos.getIndex()]);
next(pos);
}
}
super.applyPattern(stripCustom.toString());
toPattern = insertFormats(super.toPattern(), foundDescriptions);
if (containsElements(foundFormats)) {
final Format[] origFormats = getFormats();
// only loop over what we know we have, as MessageFormat on Java 1.3
// seems to provide an extra format element:
int i = 0;
for (final Iterator it = foundFormats.iterator(); it.hasNext(); i++) {
final Format f = it.next();
if (f != null) {
origFormats[i] = f;
}
}
super.setFormats(origFormats);
}
}
/**
* Throws UnsupportedOperationException - see class Javadoc for details.
*
* @param formatElementIndex format element index
* @param newFormat the new format
* @throws UnsupportedOperationException always thrown since this isn't
* supported by ExtendMessageFormat
*/
@Override
public void setFormat(final int formatElementIndex, final Format newFormat) {
throw new UnsupportedOperationException();
}
/**
* Throws UnsupportedOperationException - see class Javadoc for details.
*
* @param argumentIndex argument index
* @param newFormat the new format
* @throws UnsupportedOperationException always thrown since this isn't
* supported by ExtendMessageFormat
*/
@Override
public void setFormatByArgumentIndex(final int argumentIndex,
final Format newFormat) {
throw new UnsupportedOperationException();
}
/**
* Throws UnsupportedOperationException - see class Javadoc for details.
*
* @param newFormats new formats
* @throws UnsupportedOperationException always thrown since this isn't
* supported by ExtendMessageFormat
*/
@Override
public void setFormats(final Format[] newFormats) {
throw new UnsupportedOperationException();
}
/**
* Throws UnsupportedOperationException - see class Javadoc for details.
*
* @param newFormats new formats
* @throws UnsupportedOperationException always thrown since this isn't
* supported by ExtendMessageFormat
*/
@Override
public void setFormatsByArgumentIndex(final Format[] newFormats) {
throw new UnsupportedOperationException();
}
/**
* Check if this extended message format is equal to another object.
*
* @param obj the object to compare to
* @return true if this object equals the other, otherwise false
*/
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (obj == null) {
return false;
}
if (!Objects.equals(getClass(), obj.getClass())) {
return false;
}
final ExtendedMessageFormat rhs = (ExtendedMessageFormat) obj;
if (!Objects.equals(toPattern, rhs.toPattern)) {
return false;
}
if (!super.equals(obj)) {
return false;
}
return Objects.equals(registry, rhs.registry);
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
int result = super.hashCode();
result = HASH_SEED * result + Objects.hashCode(registry);
result = HASH_SEED * result + Objects.hashCode(toPattern);
return result;
}
/**
* Get a custom format from a format description.
*
* @param desc String
* @return Format
*/
private Format getFormat(final String desc) {
if (registry != null) {
String name = desc;
String args = null;
final int i = desc.indexOf(START_FMT);
if (i > 0) {
name = desc.substring(0, i).trim();
args = desc.substring(i + 1).trim();
}
final FormatFactory factory = registry.get(name);
if (factory != null) {
return factory.getFormat(name, args, getLocale());
}
}
return null;
}
/**
* Read the argument index from the current format element.
*
* @param pattern pattern to parse
* @param pos current parse position
* @return argument index
*/
private int readArgumentIndex(final String pattern, final ParsePosition pos) {
final int start = pos.getIndex();
seekNonWs(pattern, pos);
final StringBuilder result = new StringBuilder();
boolean error = false;
for (; !error && pos.getIndex() < pattern.length(); next(pos)) {
char c = pattern.charAt(pos.getIndex());
if (Character.isWhitespace(c)) {
seekNonWs(pattern, pos);
c = pattern.charAt(pos.getIndex());
if (c != START_FMT && c != END_FE) {
error = true;
continue;
}
}
if ((c == START_FMT || c == END_FE) && result.length() > 0) {
try {
return Integer.parseInt(result.toString());
} catch (final NumberFormatException e) { // NOPMD
// we've already ensured only digits, so unless something
// outlandishly large was specified we should be okay.
}
}
error = !Character.isDigit(c);
result.append(c);
}
if (error) {
throw new IllegalArgumentException(
"Invalid format argument index at position " + start + ": "
+ pattern.substring(start, pos.getIndex()));
}
throw new IllegalArgumentException(
"Unterminated format element at position " + start);
}
/**
* Parse the format component of a format element.
*
* @param pattern string to parse
* @param pos current parse position
* @return Format description String
*/
private String parseFormatDescription(final String pattern, final ParsePosition pos) {
final int start = pos.getIndex();
seekNonWs(pattern, pos);
final int text = pos.getIndex();
int depth = 1;
while (pos.getIndex() < pattern.length()) {
switch (pattern.charAt(pos.getIndex())) {
case START_FE:
depth++;
next(pos);
break;
case END_FE:
depth--;
if (depth == 0) {
return pattern.substring(text, pos.getIndex());
}
next(pos);
break;
case QUOTE:
getQuotedString(pattern, pos);
break;
default:
next(pos);
break;
}
}
throw new IllegalArgumentException(
"Unterminated format element at position " + start);
}
/**
* Insert formats back into the pattern for toPattern() support.
*
* @param pattern source
* @param customPatterns The custom patterns to re-insert, if any
* @return full pattern
*/
private String insertFormats(final String pattern, final ArrayList customPatterns) {
if (!containsElements(customPatterns)) {
return pattern;
}
final StringBuilder sb = new StringBuilder(pattern.length() * 2);
final ParsePosition pos = new ParsePosition(0);
int fe = -1;
int depth = 0;
while (pos.getIndex() < pattern.length()) {
final char c = pattern.charAt(pos.getIndex());
switch (c) {
case QUOTE:
appendQuotedString(pattern, pos, sb);
break;
case START_FE:
depth++;
sb.append(START_FE).append(readArgumentIndex(pattern, next(pos)));
// do not look for custom patterns when they are embedded, e.g. in a choice
if (depth == 1) {
fe++;
final String customPattern = customPatterns.get(fe);
if (customPattern != null) {
sb.append(START_FMT).append(customPattern);
}
}
break;
case END_FE:
depth--;
//$FALL-THROUGH$
default:
sb.append(c);
next(pos);
}
}
return sb.toString();
}
/**
* Consume whitespace from the current parse position.
*
* @param pattern String to read
* @param pos current position
*/
private void seekNonWs(final String pattern, final ParsePosition pos) {
int len = 0;
final char[] buffer = pattern.toCharArray();
do {
len = StringMatcherFactory.INSTANCE.splitMatcher().isMatch(buffer, pos.getIndex(), 0, buffer.length);
pos.setIndex(pos.getIndex() + len);
} while (len > 0 && pos.getIndex() < pattern.length());
}
/**
* Convenience method to advance parse position by 1.
*
* @param pos ParsePosition
* @return {@code pos}
*/
private ParsePosition next(final ParsePosition pos) {
pos.setIndex(pos.getIndex() + 1);
return pos;
}
/**
* Consume a quoted string, adding it to {@code appendTo} if
* specified.
*
* @param pattern pattern to parse
* @param pos current parse position
* @param appendTo optional StringBuilder to append
* @return {@code appendTo}
*/
private StringBuilder appendQuotedString(final String pattern, final ParsePosition pos,
final StringBuilder appendTo) {
assert pattern.toCharArray()[pos.getIndex()] == QUOTE
: "Quoted string must start with quote character";
// handle quote character at the beginning of the string
if (appendTo != null) {
appendTo.append(QUOTE);
}
next(pos);
final int start = pos.getIndex();
final char[] c = pattern.toCharArray();
final int lastHold = start;
for (int i = pos.getIndex(); i < pattern.length(); i++) {
switch (c[pos.getIndex()]) {
case QUOTE:
next(pos);
return appendTo == null ? null : appendTo.append(c, lastHold,
pos.getIndex() - lastHold);
default:
next(pos);
}
}
throw new IllegalArgumentException(
"Unterminated quoted string at position " + start);
}
/**
* Consume quoted string only.
*
* @param pattern pattern to parse
* @param pos current parse position
*/
private void getQuotedString(final String pattern, final ParsePosition pos) {
appendQuotedString(pattern, pos, null);
}
/**
* Learn whether the specified Collection contains non-null elements.
* @param coll to check
* @return {@code true} if some Object was found, {@code false} otherwise.
*/
private boolean containsElements(final Collection coll) {
if (coll == null || coll.isEmpty()) {
return false;
}
for (final Object name : coll) {
if (name != null) {
return true;
}
}
return false;
}
}