/*
* Copyright (C) 2011 Google Inc.
*
* 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.android.i18n.phonenumbers;
import com.android.i18n.phonenumbers.PhoneNumberUtil.Leniency;
import com.android.i18n.phonenumbers.Phonenumber.PhoneNumber;
import java.lang.Character.UnicodeBlock;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A stateful class that finds and extracts telephone numbers from {@linkplain CharSequence text}.
* Instances can be created using the {@linkplain PhoneNumberUtil#findNumbers factory methods} in
* {@link PhoneNumberUtil}.
*
* <p>Vanity numbers (phone numbers using alphabetic digits such as <tt>1-800-SIX-FLAGS</tt> are
* not found.
*
* <p>This class is not thread-safe.
*
* @author Tom Hofmann
*/
final class PhoneNumberMatcher implements Iterator<PhoneNumberMatch> {
/**
* The phone number pattern used by {@link #find}, similar to
* {@code PhoneNumberUtil.VALID_PHONE_NUMBER}, but with the following differences:
* <ul>
* <li>All captures are limited in order to place an upper bound to the text matched by the
* pattern.
* <ul>
* <li>Leading punctuation / plus signs are limited.
* <li>Consecutive occurrences of punctuation are limited.
* <li>Number of digits is limited.
* </ul>
* <li>No whitespace is allowed at the start or end.
* <li>No alpha digits (vanity numbers such as 1-800-SIX-FLAGS) are currently supported.
* </ul>
*/
private static final Pattern PATTERN;
/**
* Matches strings that look like publication pages. Example:
* <pre>Computing Complete Answers to Queries in the Presence of Limited Access Patterns.
* Chen Li. VLDB J. 12(3): 211-227 (2003).</pre>
*
* The string "211-227 (2003)" is not a telephone number.
*/
private static final Pattern PUB_PAGES = Pattern.compile("\\d{1,5}-+\\d{1,5}\\s{0,4}\\(\\d{1,4}");
/**
* Matches strings that look like dates using "/" as a separator. Examples: 3/10/2011, 31/10/96 or
* 08/31/95.
*/
private static final Pattern SLASH_SEPARATED_DATES =
Pattern.compile("(?:(?:[0-3]?\\d/[01]?\\d)|(?:[01]?\\d/[0-3]?\\d))/(?:[12]\\d)?\\d{2}");
/**
* Pattern to check that brackets match. Opening brackets should be closed within a phone number.
* This also checks that there is something inside the brackets. Having no brackets at all is also
* fine.
*/
private static final Pattern MATCHING_BRACKETS;
/**
* Matches white-space, which may indicate the end of a phone number and the start of something
* else (such as a neighbouring zip-code). If white-space is found, continues to match all
* characters that are not typically used to start a phone number.
*/
private static final Pattern GROUP_SEPARATOR;
/**
* Punctuation that may be at the start of a phone number - brackets and plus signs.
*/
private static final Pattern LEAD_CLASS;
static {
/* Builds the MATCHING_BRACKETS and PATTERN regular expressions. The building blocks below exist
* to make the pattern more easily understood. */
String openingParens = "(\\[\uFF08\uFF3B";
String closingParens = ")\\]\uFF09\uFF3D";
String nonParens = "[^" + openingParens + closingParens + "]";
/* Limit on the number of pairs of brackets in a phone number. */
String bracketPairLimit = limit(0, 3);
/*
* An opening bracket at the beginning may not be closed, but subsequent ones should be. It's
* also possible that the leading bracket was dropped, so we shouldn't be surprised if we see a
* closing bracket first. We limit the sets of brackets in a phone number to four.
*/
MATCHING_BRACKETS = Pattern.compile(
"(?:[" + openingParens + "])?" + "(?:" + nonParens + "+" + "[" + closingParens + "])?" +
nonParens + "+" +
"(?:[" + openingParens + "]" + nonParens + "+[" + closingParens + "])" + bracketPairLimit +
nonParens + "*");
/* Limit on the number of leading (plus) characters. */
String leadLimit = limit(0, 2);
/* Limit on the number of consecutive punctuation characters. */
String punctuationLimit = limit(0, 4);
/* The maximum number of digits allowed in a digit-separated block. As we allow all digits in a
* single block, set high enough to accommodate the entire national number and the international
* country code. */
int digitBlockLimit =
PhoneNumberUtil.MAX_LENGTH_FOR_NSN + PhoneNumberUtil.MAX_LENGTH_COUNTRY_CODE;
/* Limit on the number of blocks separated by punctuation. Uses digitBlockLimit since some
* formats use spaces to separate each digit. */
String blockLimit = limit(0, digitBlockLimit);
/* A punctuation sequence allowing white space. */
String punctuation = "[" + PhoneNumberUtil.VALID_PUNCTUATION + "]" + punctuationLimit;
/* A digits block without punctuation. */
String digitSequence = "\\p{Nd}" + limit(1, digitBlockLimit);
String leadClassChars = openingParens + PhoneNumberUtil.PLUS_CHARS;
String leadClass = "[" + leadClassChars + "]";
LEAD_CLASS = Pattern.compile(leadClass);
GROUP_SEPARATOR = Pattern.compile("\\p{Z}" + "[^" + leadClassChars + "\\p{Nd}]*");
/* Phone number pattern allowing optional punctuation. */
PATTERN = Pattern.compile(
"(?:" + leadClass + punctuation + ")" + leadLimit +
digitSequence + "(?:" + punctuation + digitSequence + ")" + blockLimit +
"(?:" + PhoneNumberUtil.EXTN_PATTERNS_FOR_MATCHING + ")?",
PhoneNumberUtil.REGEX_FLAGS);
}
/** Returns a regular expression quantifier with an upper and lower limit. */
private static String limit(int lower, int upper) {
if ((lower < 0) || (upper <= 0) || (upper < lower)) {
throw new IllegalArgumentException();
}
return "{" + lower + "," + upper + "}";
}
/** The potential states of a PhoneNumberMatcher. */
private enum State {
NOT_READY, READY, DONE
}
/** The phone number utility. */
private final PhoneNumberUtil phoneUtil;
/** The text searched for phone numbers. */
private final CharSequence text;
/**
* The region (country) to assume for phone numbers without an international prefix, possibly
* null.
*/
private final String preferredRegion;
/** The degree of validation requested. */
private final Leniency leniency;
/** The maximum number of retries after matching an invalid number. */
private long maxTries;
/** The iteration tristate. */
private State state = State.NOT_READY;
/** The last successful match, null unless in {@link State#READY}. */
private PhoneNumberMatch lastMatch = null;
/** The next index to start searching at. Undefined in {@link State#DONE}. */
private int searchIndex = 0;
/**
* Creates a new instance. See the factory methods in {@link PhoneNumberUtil} on how to obtain a
* new instance.
*
* @param util the phone number util to use
* @param text the character sequence that we will search, null for no text
* @param country the country to assume for phone numbers not written in international format
* (with a leading plus, or with the international dialing prefix of the
* specified region). May be null or "ZZ" if only numbers with a
* leading plus should be considered.
* @param leniency the leniency to use when evaluating candidate phone numbers
* @param maxTries the maximum number of invalid numbers to try before giving up on the text.
* This is to cover degenerate cases where the text has a lot of false positives
* in it. Must be {@code >= 0}.
*/
PhoneNumberMatcher(PhoneNumberUtil util, CharSequence text, String country, Leniency leniency,
long maxTries) {
if ((util == null) || (leniency == null)) {
throw new NullPointerException();
}
if (maxTries < 0) {
throw new IllegalArgumentException();
}
this.phoneUtil = util;
this.text = (text != null) ? text : "";
this.preferredRegion = country;
this.leniency = leniency;
this.maxTries = maxTries;
}
public boolean hasNext() {
if (state == State.NOT_READY) {
lastMatch = find(searchIndex);
if (lastMatch == null) {
state = State.DONE;
} else {
searchIndex = lastMatch.end();
state = State.READY;
}
}
return state == State.READY;
}
public PhoneNumberMatch next() {
// Check the state and find the next match as a side-effect if necessary.
if (!hasNext()) {
throw new NoSuchElementException();
}
// Don't retain that memory any longer than necessary.
PhoneNumberMatch result = lastMatch;
lastMatch = null;
state = State.NOT_READY;
return result;
}
/**
* Attempts to find the next subsequence in the searched sequence on or after {@code searchIndex}
* that represents a phone number. Returns the next match, null if none was found.
*
* @param index the search index to start searching at
* @return the phone number match found, null if none can be found
*/
private PhoneNumberMatch find(int index) {
Matcher matcher = PATTERN.matcher(text);
while ((maxTries > 0) && matcher.find(index)) {
int start = matcher.start();
CharSequence candidate = text.subSequence(start, matcher.end());
// Check for extra numbers at the end.
// TODO: This is the place to start when trying to support extraction of multiple phone number
// from split notations (+41 79 123 45 67 / 68).
candidate = trimAfterFirstMatch(PhoneNumberUtil.SECOND_NUMBER_START_PATTERN, candidate);
PhoneNumberMatch match = extractMatch(candidate, start);
if (match != null) {
return match;
}
index = start + candidate.length();
maxTries--;
}
return null;
}
/**
* Trims away any characters after the first match of {@code pattern} in {@code candidate},
* returning the trimmed version.
*/
private static CharSequence trimAfterFirstMatch(Pattern pattern, CharSequence candidate) {
Matcher trailingCharsMatcher = pattern.matcher(candidate);
if (trailingCharsMatcher.find()) {
candidate = candidate.subSequence(0, trailingCharsMatcher.start());
}
return candidate;
}
/**
* Helper method to determine if a character is a Latin-script letter or not. For our purposes,
* combining marks should also return true since we assume they have been added to a preceding
* Latin character.
*/
static boolean isLatinLetter(char letter) {
// Combining marks are a subset of non-spacing-mark.
if (!Character.isLetter(letter) && Character.getType(letter) != Character.NON_SPACING_MARK) {
return false;
}
UnicodeBlock block = UnicodeBlock.of(letter);
return block.equals(UnicodeBlock.BASIC_LATIN) ||
block.equals(UnicodeBlock.LATIN_1_SUPPLEMENT) ||
block.equals(UnicodeBlock.LATIN_EXTENDED_A) ||
block.equals(UnicodeBlock.LATIN_EXTENDED_ADDITIONAL) ||
block.equals(UnicodeBlock.LATIN_EXTENDED_B) ||
block.equals(UnicodeBlock.COMBINING_DIACRITICAL_MARKS);
}
private static boolean isCurrencySymbol(char character) {
return Character.getType(character) == Character.CURRENCY_SYMBOL;
}
/**
* Attempts to extract a match from a {@code candidate} character sequence.
*
* @param candidate the candidate text that might contain a phone number
* @param offset the offset of {@code candidate} within {@link #text}
* @return the match found, null if none can be found
*/
private PhoneNumberMatch extractMatch(CharSequence candidate, int offset) {
// Skip a match that is more likely a publication page reference or a date.
if (PUB_PAGES.matcher(candidate).find() || SLASH_SEPARATED_DATES.matcher(candidate).find()) {
return null;
}
// Try to come up with a valid match given the entire candidate.
String rawString = candidate.toString();
PhoneNumberMatch match = parseAndVerify(rawString, offset);
if (match != null) {
return match;
}
// If that failed, try to find an "inner match" - there might be a phone number within this
// candidate.
return extractInnerMatch(rawString, offset);
}
/**
* Attempts to extract a match from {@code candidate} if the whole candidate does not qualify as a
* match.
*
* @param candidate the candidate text that might contain a phone number
* @param offset the current offset of {@code candidate} within {@link #text}
* @return the match found, null if none can be found
*/
private PhoneNumberMatch extractInnerMatch(String candidate, int offset) {
// Try removing either the first or last "group" in the number and see if this gives a result.
// We consider white space to be a possible indication of the start or end of the phone number.
Matcher groupMatcher = GROUP_SEPARATOR.matcher(candidate);
if (groupMatcher.find()) {
// Try the first group by itself.
CharSequence firstGroupOnly = candidate.substring(0, groupMatcher.start());
firstGroupOnly = trimAfterFirstMatch(PhoneNumberUtil.UNWANTED_END_CHAR_PATTERN,
firstGroupOnly);
PhoneNumberMatch match = parseAndVerify(firstGroupOnly.toString(), offset);
if (match != null) {
return match;
}
maxTries--;
int withoutFirstGroupStart = groupMatcher.end();
// Try the rest of the candidate without the first group.
CharSequence withoutFirstGroup = candidate.substring(withoutFirstGroupStart);
withoutFirstGroup = trimAfterFirstMatch(PhoneNumberUtil.UNWANTED_END_CHAR_PATTERN,
withoutFirstGroup);
match = parseAndVerify(withoutFirstGroup.toString(), offset + withoutFirstGroupStart);
if (match != null) {
return match;
}
maxTries--;
if (maxTries > 0) {
int lastGroupStart = withoutFirstGroupStart;
while (groupMatcher.find()) {
// Find the last group.
lastGroupStart = groupMatcher.start();
}
CharSequence withoutLastGroup = candidate.substring(0, lastGroupStart);
withoutLastGroup = trimAfterFirstMatch(PhoneNumberUtil.UNWANTED_END_CHAR_PATTERN,
withoutLastGroup);
if (withoutLastGroup.equals(firstGroupOnly)) {
// If there are only two groups, then the group "without the last group" is the same as
// the first group. In these cases, we don't want to re-check the number group, so we exit
// already.
return null;
}
match = parseAndVerify(withoutLastGroup.toString(), offset);
if (match != null) {
return match;
}
maxTries--;
}
}
return null;
}
/**
* Parses a phone number from the {@code candidate} using {@link PhoneNumberUtil#parse} and
* verifies it matches the requested {@link #leniency}. If parsing and verification succeed, a
* corresponding {@link PhoneNumberMatch} is returned, otherwise this method returns null.
*
* @param candidate the candidate match
* @param offset the offset of {@code candidate} within {@link #text}
* @return the parsed and validated phone number match, or null
*/
private PhoneNumberMatch parseAndVerify(String candidate, int offset) {
try {
// Check the candidate doesn't contain any formatting which would indicate that it really
// isn't a phone number.
if (!MATCHING_BRACKETS.matcher(candidate).matches()) {
return null;
}
// If leniency is set to VALID or stricter, we also want to skip numbers that are surrounded
// by Latin alphabetic characters, to skip cases like abc8005001234 or 8005001234def.
if (leniency.compareTo(Leniency.VALID) >= 0) {
// If the candidate is not at the start of the text, and does not start with phone-number
// punctuation, check the previous character.
if (offset > 0 && !LEAD_CLASS.matcher(candidate).lookingAt()) {
char previousChar = text.charAt(offset - 1);
// We return null if it is a latin letter or a currency symbol.
if (isCurrencySymbol(previousChar) || isLatinLetter(previousChar)) {
return null;
}
}
int lastCharIndex = offset + candidate.length();
if (lastCharIndex < text.length()) {
char nextChar = text.charAt(lastCharIndex);
if (isCurrencySymbol(nextChar) || isLatinLetter(nextChar)) {
return null;
}
}
}
PhoneNumber number = phoneUtil.parse(candidate, preferredRegion);
if (leniency.verify(number, candidate, phoneUtil)) {
return new PhoneNumberMatch(offset, candidate, number);
}
} catch (NumberParseException e) {
// ignore and continue
}
return null;
}
/**
* Always throws {@link UnsupportedOperationException} as removal is not supported.
*/
public void remove() {
throw new UnsupportedOperationException();
}
}