regexodus.regex.Matcher Maven / Gradle / Ivy
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package regexodus.regex;
import regexodus.PerlSubstitution;
import regexodus.Replacer;
/**
* Created by Tommy Ettinger on 6/7/2016.
*/
public class Matcher implements MatchResult {
private regexodus.Matcher matcher;
private Pattern pattern;
/**
* No default constructor.
*/
Matcher() {
}
/**
* All matchers have the state used by Pattern during a match.
*/
Matcher(Pattern parent, CharSequence text) {
pattern = parent;
matcher = new regexodus.Matcher(parent.internal, text);
}
/**
* Returns the pattern that is interpreted by this matcher.
*
* @return The pattern for which this matcher was created
*/
public Pattern pattern() {
return pattern;
}
/**
* Returns the match state of this matcher as a {@link MatchResult}.
* The result is unaffected by subsequent operations performed upon this
* matcher.
*
* @return a MatchResult with the state of this matcher
* @since 1.5
*/
public MatchResult toMatchResult() {
return matcher.copy();
}
/**
* Changes the Pattern that this Matcher uses to
* find matches with.
*
* This method causes this matcher to lose information
* about the groups of the last match that occurred. The
* matcher's position in the input is maintained and its
* last append position is unaffected.
*
* @param newPattern
* The new pattern used by this matcher
* @return This matcher
* @throws IllegalArgumentException
* If newPattern is null
* @since 1.5
*/
public Matcher usePattern(Pattern newPattern) {
if (newPattern == null)
throw new IllegalArgumentException("Pattern cannot be null");
matcher.setPattern(newPattern.internal);
return this;
}
/**
* Resets this matcher.
*
* Resetting a matcher discards all of its explicit state information
* and sets its append position to zero. The matcher's region is set to the
* default region, which is its entire character sequence. The anchoring
* and transparency of this matcher's region boundaries are unaffected.
*
* @return This matcher
*/
public Matcher reset() {
matcher.flush();
return this;
}
/**
* Resets this matcher with a new input sequence.
*
*
Resetting a matcher discards all of its explicit state information
* and sets its append position to zero. The matcher's region is set to
* the default region, which is its entire character sequence. The
* anchoring and transparency of this matcher's region boundaries are
* unaffected.
*
* @param input
* The new input character sequence
*
* @return This matcher
*/
public Matcher reset(CharSequence input) {
matcher.setTarget(input);
return reset();
}
/**
* Returns the start index of the match.
*
* @return The index of the first character matched
*/
@Override
public int start() {
return matcher.start();
}
/**
* Returns the start index of the subsequence captured by the given group
* during this match.
*
* Capturing groups are indexed from left
* to right, starting at one. Group zero denotes the entire pattern, so
* the expression m.start(0) is equivalent to
* m.start().
*
* @param group The index of a capturing group in this matcher's pattern
* @return The index of the first character captured by the group,
* or -1 if the match was successful but the group
* itself did not match anything
*/
@Override
public int start(int group) {
return matcher.start(group);
}
/**
* Returns the start index of the subsequence captured by the given
* named-capturing group during the previous match operation.
*
* @param name The name of a named capturing group in this matcher's pattern
* @return The index of the first character captured by the group,
* or -1 if the match was successful but the group
* itself did not match anything
*/
@Override
public int start(String name) {
return matcher.start(name);
}
/**
* Returns the offset after the last character of the subsequence captured
* by the given named-capturing group during the previous match operation.
*
* @param name The name of a named capturing group in this matcher's pattern
* @return The offset after the last character captured by the group,
* or -1 if the match was successful
* but the group itself did not match anything
*/
@Override
public int end(String name) {
return matcher.end(1);
}
/**
* Returns the offset after the last character matched.
*
* @return The offset after the last character matched
*/
@Override
public int end() {
return matcher.end();
}
/**
* Returns the offset after the last character of the subsequence
* captured by the given group during this match.
*
* Capturing groups are indexed from left
* to right, starting at one. Group zero denotes the entire pattern, so
* the expression m.end(0) is equivalent to
* m.end().
*
* @param group The index of a capturing group in this matcher's pattern
* @return The offset after the last character captured by the group,
* or -1 if the match was successful
* but the group itself did not match anything
*/
@Override
public int end(int group) {
return matcher.end(group);
}
/**
* Returns the input subsequence matched by the previous match.
*
* For a matcher m with input sequence s,
* the expressions m.group() and
* s.substring(m.start(), m.end())
* are equivalent.
*
* Note that some patterns, for example a*, match the empty
* string. This method will return the empty string when the pattern
* successfully matches the empty string in the input.
*
* @return The (possibly empty) subsequence matched by the previous match,
* in string form
*/
@Override
public String group() {
return matcher.group();
}
/**
* Returns the input subsequence captured by the given group during the
* previous match operation.
*
* For a matcher m, input sequence s, and group index
* g, the expressions m.group(g) and
* s.substring(m.start(g), m.end(g))
* are equivalent.
*
* Capturing groups are indexed from left
* to right, starting at one. Group zero denotes the entire pattern, so
* the expression m.group(0) is equivalent to m.group().
*
* If the match was successful but the group specified failed to match
* any part of the input sequence, then null is returned. Note
* that some groups, for example (a*), match the empty string.
* This method will return the empty string when such a group successfully
* matches the empty string in the input.
*
* @param group The index of a capturing group in this matcher's pattern
* @return The (possibly empty) subsequence captured by the group
* during the previous match, or null if the group
* failed to match part of the input
*/
@Override
public String group(int group) {
return matcher.group(group);
}
/**
* Returns the input subsequence captured by the given named group during the
* previous match operation.
*
* Like {@link #group(int) group} but for named groups instead of numbered.
* @param name
* The name of a capturing group in this matcher's pattern
*
* @return The (possibly empty) subsequence captured by the group
* during the previous match, or null if the group
* failed to match part of the input
*/
public String group(String name)
{
return matcher.group(name);
}
/**
* Returns the number of capturing groups in this match result's pattern.
*
* Group zero denotes the entire pattern by convention. It is not
* included in this count.
*
* Any non-negative integer smaller than or equal to the value
* returned by this method is guaranteed to be a valid group index for
* this matcher.
*
* @return The number of capturing groups in this matcher's pattern
*/
@Override
public int groupCount() {
return matcher.groupCount();
}
/**
* Attempts to match the entire region against the pattern.
*
*
If the match succeeds then more information can be obtained via the
* start, end, and group methods.
*
* @return true if, and only if, the entire region sequence
* matches this matcher's pattern
*/
public boolean matches() {
return matcher.matches();
}
/**
* Attempts to find the next subsequence of the input sequence that matches
* the pattern.
*
* This method starts at the beginning of this matcher's region, or, if
* a previous invocation of the method was successful and the matcher has
* not since been reset, at the first character not matched by the previous
* match.
*
*
If the match succeeds then more information can be obtained via the
* start, end, and group methods.
*
* @return true if, and only if, a subsequence of the input
* sequence matches this matcher's pattern
*/
public boolean find() {
return matcher.find();
}
/**
* Resets this matcher and then attempts to find the next subsequence of
* the input sequence that matches the pattern, starting at the specified
* index.
*
* If the match succeeds then more information can be obtained via the
* start, end, and group methods, and subsequent
* invocations of the {@link #find()} method will start at the first
* character not matched by this match.
*
* @throws IndexOutOfBoundsException
* If start is less than zero or if start is greater than the
* length of the input sequence.
*
* @return true if, and only if, a subsequence of the input
* sequence starting at the given index matches this matcher's
* pattern
*/
public boolean find(int start) {
int limit = matcher.targetEnd();
if ((start < 0) || (start > limit))
throw new IndexOutOfBoundsException("Illegal start index");
reset();
matcher.setPosition(start);
return matcher.find();
}
/**
* Attempts to match the input sequence, starting at the beginning of the
* region, against the pattern.
*
* Like the {@link #matches matches} method, this method always starts
* at the beginning of the region; unlike that method, it does not
* require that the entire region be matched.
*
*
If the match succeeds then more information can be obtained via the
* start, end, and group methods.
*
* @return true if, and only if, a prefix of the input
* sequence matches this matcher's pattern
*/
public boolean lookingAt() {
return matcher.search(regexodus.Matcher.ACCEPT_INCOMPLETE);
}
/**
* Returns a literal replacement String for the specified
* String.
*
* This method produces a String that will work
* as a literal replacement s in the
* appendReplacement method of the {@link Matcher} class.
* The String produced will match the sequence of characters
* in s treated as a literal sequence. Slashes ('\') and
* dollar signs ('$') will be given no special meaning.
*
* @param s The string to be literalized
* @return A literal string replacement
*/
public static String quoteReplacement(String s) {
if ((s.indexOf('\\') == -1) && (s.indexOf('$') == -1))
return s;
StringBuilder sb = new StringBuilder();
for (int i=0; i This method performs the following actions:
*
*
*
* It reads characters from the input sequence, starting at the
* append position, and appends them to the given string buffer. It
* stops after reading the last character preceding the previous match,
* that is, the character at index {@link
* #start()} - 1.
It appends the given replacement string to the string buffer.
*
It sets the append position of this matcher to the index of
* the last character matched, plus one, that is, to {@link #end()}.
*
*
* The replacement string may contain references to subsequences
* captured during the previous match: Each occurrence of
* ${name} or $g
* will be replaced by the result of evaluating the corresponding
* {@link #group(String) group(name)} or {@link #group(int) group(g)}
* respectively. For $g,
* the first number after the $ is always treated as part of
* the group reference. Subsequent numbers are incorporated into g if
* they would form a legal group reference. Only the numerals '0'
* through '9' are considered as potential components of the group
* reference. If the second group matched the string "foo", for
* example, then passing the replacement string "$2bar" would
* cause "foobar" to be appended to the string buffer. A dollar
* sign ($) may be included as a literal in the replacement
* string by preceding it with a backslash (\$).
*
*
Note that backslashes (\) and dollar signs ($) in
* the replacement string may cause the results to be different than if it
* were being treated as a literal replacement string. Dollar signs may be
* treated as references to captured subsequences as described above, and
* backslashes are used to escape literal characters in the replacement
* string.
*
*
This method is intended to be used in a loop together with the
* {@link #appendTail appendTail} and {@link #find find} methods. The
* following code, for example, writes one dog two dogs in the
* yard to the standard-output stream:
*
*
* Pattern p = Pattern.compile("cat");
* Matcher m = p.matcher("one cat two cats in the yard");
* StringBuffer sb = new StringBuffer();
* while (m.find()) {
* m.appendReplacement(sb, "dog");
* }
* m.appendTail(sb);
* System.out.println(sb.toString());
*
* @param sb
* The target string buffer
*
* @param replacement
* The replacement string
*
* @return This matcher
*
* @throws IllegalStateException
* If no match has yet been attempted,
* or if the previous match operation failed
*
* @throws IllegalArgumentException
* If the replacement string refers to a named-capturing
* group that does not exist in the pattern
*
* @throws IndexOutOfBoundsException
* If the replacement string refers to a capturing group
* that does not exist in the pattern
*/
public Matcher appendReplacement(StringBuffer sb, String replacement) {
Replacer rep = pattern.internal.replacer(replacement);
Replacer.replaceStep(matcher, new PerlSubstitution(replacement), Replacer.wrap(sb));
return this;
}
/**
* Implements a terminal append-and-replace step.
*
* This method reads characters from the input sequence, starting at
* the append position, and appends them to the given string buffer. It is
* intended to be invoked after one or more invocations of the {@link
* #appendReplacement appendReplacement} method in order to copy the
* remainder of the input sequence.
*
* @param sb
* The target string buffer
*
* @return The target string buffer
*/
public StringBuffer appendTail(StringBuffer sb) {
matcher.getGroup(regexodus.MatchResult.TARGET, Replacer.wrap(sb));
return sb;
}
/**
* Replaces every subsequence of the input sequence that matches the
* pattern with the given replacement string.
*
* This method first resets this matcher. It then scans the input
* sequence looking for matches of the pattern. Characters that are not
* part of any match are appended directly to the result string; each match
* is replaced in the result by the replacement string. The replacement
* string may contain references to captured subsequences as in the {@link
* #appendReplacement appendReplacement} method.
*
*
Note that backslashes (\) and dollar signs ($) in
* the replacement string may cause the results to be different than if it
* were being treated as a literal replacement string. Dollar signs may be
* treated as references to captured subsequences as described above, and
* backslashes are used to escape literal characters in the replacement
* string.
*
*
Given the regular expression a*b, the input
* "aabfooaabfooabfoob", and the replacement string
* "-", an invocation of this method on a matcher for that
* expression would yield the string "-foo-foo-foo-".
*
*
Invoking this method changes this matcher's state. If the matcher
* is to be used in further matching operations then it should first be
* reset.
*
* @param replacement
* The replacement string
*
* @return The string constructed by replacing each matching subsequence
* by the replacement string, substituting captured subsequences
* as needed
*/
public String replaceAll(String replacement) {
reset();
return matcher.replaceAll(replacement);
}
/**
* Replaces the first subsequence of the input sequence that matches the
* pattern with the given replacement string.
*
* This method first resets this matcher. It then scans the input
* sequence looking for a match of the pattern. Characters that are not
* part of the match are appended directly to the result string; the match
* is replaced in the result by the replacement string. The replacement
* string may contain references to captured subsequences.
*
* Note that backslashes (\) and dollar signs ($) in
* the replacement string may cause the results to be different than if it
* were being treated as a literal replacement string. Dollar signs may be
* treated as references to captured subsequences as described above, and
* backslashes are used to escape literal characters in the replacement
* string.
*
* Given the regular expression dog, the input
* "zzzdogzzzdogzzz", and the replacement string
* "cat", an invocation of this method on a matcher for that
* expression would yield the string "zzzcatzzzdogzzz".
*
* Invoking this method changes this matcher's state. If the matcher
* is to be used in further matching operations then it should first be
* reset.
*
* @param replacement
* The replacement string
* @return The string constructed by replacing the first matching
* subsequence by the replacement string, substituting captured
* subsequences as needed
*/
public String replaceFirst(String replacement) {
if (replacement == null)
throw new NullPointerException("replacement");
reset();
return matcher.replaceFirst(replacement);
}
/**
* Sets the limits of this matcher's region. The region is the part of the
* input sequence that will be searched to find a match. Invoking this
* method resets the matcher, and then sets the region to start at the
* index specified by the start parameter and end at the
* index specified by the end parameter.
*
* @param start
* The index to start searching at (inclusive)
* @param end
* The index to end searching at (exclusive)
* @throws IndexOutOfBoundsException
* If start or end is less than zero, if
* start is greater than the length of the input sequence, if
* end is greater than the length of the input sequence, or if
* start is greater than end.
* @return this matcher
* @since 1.5
*/
public Matcher region(int start, int end) {
if ((start < 0) || (start < 0))
throw new IndexOutOfBoundsException("start");
if ((end < 0) || (end > matcher.dataEnd()))
throw new IndexOutOfBoundsException("end");
if (start > end)
throw new IndexOutOfBoundsException("start > end");
matcher.setTarget(matcher.targetChars(), start, end - start);
return this;
}
/**
* Reports the start index of this matcher's region. The
* searches this matcher conducts are limited to finding matches
* within {@link #regionStart regionStart} (inclusive) and
* {@link #regionEnd regionEnd} (exclusive).
*
* @return The starting point of this matcher's region
* @since 1.5
*/
public int regionStart() {
return matcher.targetStart();
}
/**
* Reports the end index (exclusive) of this matcher's region.
* The searches this matcher conducts are limited to finding matches
* within {@link #regionStart regionStart} (inclusive) and
* {@link #regionEnd regionEnd} (exclusive).
*
* @return the ending point of this matcher's region
* @since 1.5
*/
public int regionEnd() {
return matcher.targetEnd();
}
/**
*/
public boolean hasTransparentBounds() {
throw new UnsupportedOperationException("Not implemented");
}
/**
*/
public Matcher useTransparentBounds(boolean b) {
throw new UnsupportedOperationException("Not implemented");
}
/**
* Not implemented.
* @return always throws an Exception.
* @throws UnsupportedOperationException every time.
*/
public boolean hasAnchoringBounds() {
throw new UnsupportedOperationException("Not implemented");
}
/**
* Not implemented.
* @param b a boolean indicating whether or not to use anchoring bounds.
* @return this matcher
*/
public Matcher useAnchoringBounds(boolean b) {
throw new UnsupportedOperationException("Not implemented");
}
/**
* Returns the string representation of this matcher. The
* string representation of a Matcher contains information
* that may be useful for debugging. The exact format is unspecified.
*
* @return The string representation of this matcher
*/
public String toString() {
return matcher.toString();
}
/**
* Not implemented.
*/
public boolean hitEnd() {
throw new UnsupportedOperationException("Not implemented");
}
/**
* Not implemented.
*/
public boolean requireEnd() {
throw new UnsupportedOperationException("Not implemented");
}
}