package org.apache.lucene.analysis;
import java.util.Arrays;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import org.apache.lucene.util.CharacterUtils;
import org.apache.lucene.util.Version;
/**
* 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.
*/
/**
* A simple class that stores Strings as char[]'s in a
* hash table. Note that this is not a general purpose
* class. For example, it cannot remove items from the
* set, nor does it resize its hash table to be smaller,
* etc. It is designed to be quick to test if a char[]
* is in the set without the necessity of converting it
* to a String first.
* <p>You must specify the required {@link Version}
* compatibility when creating {@link CharArraySet}:
* <ul>
* <li> As of 3.1, supplementary characters are
* properly lowercased.</li>
* </ul>
* Before 3.1 supplementary characters could not be
* lowercased correctly due to the lack of Unicode 4
* support in JDK 1.4. To use instances of
* {@link CharArraySet} with the behavior before Lucene
* 3.1 pass a {@link Version} < 3.1 to the constructors.
* <P>
* <em>Please note:</em> This class implements {@link java.util.Set Set} but
* does not behave like it should in all cases. The generic type is
* {@code Set<Object>}, because you can add any object to it,
* that has a string representation. The add methods will use
* {@link Object#toString} and store the result using a {@code char[]}
* buffer. The same behavior have the {@code contains()} methods.
* The {@link #iterator()} returns an {@code Iterator<String>}.
* For type safety also {@link #stringIterator()} is provided.
*/
public class CharArraySet extends AbstractSet<Object> {
private final static int INIT_SIZE = 8;
private char[][] entries;
private int count;
private final boolean ignoreCase;
public static final CharArraySet EMPTY_SET = new EmptyCharArraySet();
private final CharacterUtils charUtils;
private final Version matchVersion;
/**
* Create set with enough capacity to hold startSize terms
*
* @param matchVersion
* compatibility match version see <a href="#version">Version
* note</a> above for details.
* @param startSize
* the initial capacity
* @param ignoreCase
* <code>false</code> if and only if the set should be case sensitive
* otherwise <code>true</code>.
*/
public CharArraySet(Version matchVersion, int startSize, boolean ignoreCase) {
this.ignoreCase = ignoreCase;
int size = INIT_SIZE;
while(startSize + (startSize>>2) > size)
size <<= 1;
entries = new char[size][];
this.charUtils = CharacterUtils.getInstance(matchVersion);
this.matchVersion = matchVersion;
}
/**
* Creates a set from a Collection of objects.
*
* @param matchVersion
* compatibility match version see <a href="#version">Version
* note</a> above for details.
* @param c
* a collection whose elements to be placed into the set
* @param ignoreCase
* <code>false</code> if and only if the set should be case sensitive
* otherwise <code>true</code>.
*/
public CharArraySet(Version matchVersion, Collection<? extends Object> c, boolean ignoreCase) {
this(matchVersion, c.size(), ignoreCase);
addAll(c);
}
/**
* Creates a set with enough capacity to hold startSize terms
*
* @param startSize
* the initial capacity
* @param ignoreCase
* <code>false</code> if and only if the set should be case sensitive
* otherwise <code>true</code>.
* @deprecated use {@link #CharArraySet(Version, int, boolean)} instead
*/
@Deprecated
public CharArraySet(int startSize, boolean ignoreCase) {
this(Version.LUCENE_30, startSize, ignoreCase);
}
/**
* Creates a set from a Collection of objects.
*
* @param c
* a collection whose elements to be placed into the set
* @param ignoreCase
* <code>false</code> if and only if the set should be case sensitive
* otherwise <code>true</code>.
* @deprecated use {@link #CharArraySet(Version, Collection, boolean)} instead
*/
@Deprecated
public CharArraySet(Collection<? extends Object> c, boolean ignoreCase) {
this(Version.LUCENE_30, c.size(), ignoreCase);
addAll(c);
}
/** Create set from entries */
private CharArraySet(Version matchVersion, char[][] entries, boolean ignoreCase, int count){
this.entries = entries;
this.ignoreCase = ignoreCase;
this.count = count;
this.charUtils = CharacterUtils.getInstance(matchVersion);
this.matchVersion = matchVersion;
}
/** Clears all entries in this set. This method is supported for reusing, but not {@link Set#remove}. */
@Override
public void clear() {
count = 0;
Arrays.fill(entries, null);
}
/** true if the <code>len</code> chars of <code>text</code> starting at <code>off</code>
* are in the set */
public boolean contains(char[] text, int off, int len) {
return entries[getSlot(text, off, len)] != null;
}
/** true if the <code>CharSequence</code> is in the set */
public boolean contains(CharSequence cs) {
return entries[getSlot(cs)] != null;
}
private int getSlot(char[] text, int off, int len) {
int code = getHashCode(text, off, len);
int pos = code & (entries.length-1);
char[] text2 = entries[pos];
if (text2 != null && !equals(text, off, len, text2)) {
final int inc = ((code>>8)+code)|1;
do {
code += inc;
pos = code & (entries.length-1);
text2 = entries[pos];
} while (text2 != null && !equals(text, off, len, text2));
}
return pos;
}
/** Returns true if the String is in the set */
private int getSlot(CharSequence text) {
int code = getHashCode(text);
int pos = code & (entries.length-1);
char[] text2 = entries[pos];
if (text2 != null && !equals(text, text2)) {
final int inc = ((code>>8)+code)|1;
do {
code += inc;
pos = code & (entries.length-1);
text2 = entries[pos];
} while (text2 != null && !equals(text, text2));
}
return pos;
}
/** Add this CharSequence into the set */
public boolean add(CharSequence text) {
return add(text.toString()); // could be more efficient
}
/** Add this String into the set */
public boolean add(String text) {
return add(text.toCharArray());
}
/** Add this char[] directly to the set.
* If ignoreCase is true for this Set, the text array will be directly modified.
* The user should never modify this text array after calling this method.
*/
public boolean add(char[] text) {
if (ignoreCase)
for(int i=0;i<text.length;){
i += Character.toChars(
Character.toLowerCase(
charUtils.codePointAt(text, i)), text, i);
}
int slot = getSlot(text, 0, text.length);
if (entries[slot] != null) return false;
entries[slot] = text;
count++;
if (count + (count>>2) > entries.length) {
rehash();
}
return true;
}
private boolean equals(char[] text1, int off, int len, char[] text2) {
if (len != text2.length)
return false;
final int limit = off+len;
if (ignoreCase) {
for(int i=0;i<len;) {
final int codePointAt = charUtils.codePointAt(text1, off+i, limit);
if (Character.toLowerCase(codePointAt) != charUtils.codePointAt(text2, i))
return false;
i += Character.charCount(codePointAt);
}
} else {
for(int i=0;i<len;i++) {
if (text1[off+i] != text2[i])
return false;
}
}
return true;
}
private boolean equals(CharSequence text1, char[] text2) {
int len = text1.length();
if (len != text2.length)
return false;
if (ignoreCase) {
for(int i=0;i<len;) {
final int codePointAt = charUtils.codePointAt(text1, i);
if (Character.toLowerCase(codePointAt) != charUtils.codePointAt(text2, i))
return false;
i += Character.charCount(codePointAt);
}
} else {
for(int i=0;i<len;i++) {
if (text1.charAt(i) != text2[i])
return false;
}
}
return true;
}
private void rehash() {
final int newSize = 2*entries.length;
char[][] oldEntries = entries;
entries = new char[newSize][];
for(int i=0;i<oldEntries.length;i++) {
char[] text = oldEntries[i];
if (text != null) {
// todo: could be faster... no need to compare strings on collision
entries[getSlot(text,0,text.length)] = text;
}
}
}
private int getHashCode(char[] text, int offset, int len) {
int code = 0;
final int stop = offset + len;
if (ignoreCase) {
for (int i=offset; i<stop;) {
final int codePointAt = charUtils.codePointAt(text, i, stop);
code = code*31 + Character.toLowerCase(codePointAt);
i += Character.charCount(codePointAt);
}
} else {
for (int i=offset; i<stop; i++) {
code = code*31 + text[i];
}
}
return code;
}
private int getHashCode(CharSequence text) {
int code = 0;
int len = text.length();
if (ignoreCase) {
for (int i=0; i<len;) {
int codePointAt = charUtils.codePointAt(text, i);
code = code*31 + Character.toLowerCase(codePointAt);
i += Character.charCount(codePointAt);
}
} else {
for (int i=0; i<len; i++) {
code = code*31 + text.charAt(i);
}
}
return code;
}
@Override
public int size() {
return count;
}
@Override
public boolean isEmpty() {
return count==0;
}
@Override
public boolean contains(Object o) {
if (o instanceof char[]) {
final char[] text = (char[])o;
return contains(text, 0, text.length);
}
return contains(o.toString());
}
@Override
public boolean add(Object o) {
if (o instanceof char[]) {
return add((char[])o);
}
return add(o.toString());
}
/**
* Returns an unmodifiable {@link CharArraySet}. This allows to provide
* unmodifiable views of internal sets for "read-only" use.
*
* @param set
* a set for which the unmodifiable set is returned.
* @return an new unmodifiable {@link CharArraySet}.
* @throws NullPointerException
* if the given set is <code>null</code>.
*/
public static CharArraySet unmodifiableSet(CharArraySet set) {
if (set == null)
throw new NullPointerException("Given set is null");
if (set == EMPTY_SET)
return EMPTY_SET;
if (set instanceof UnmodifiableCharArraySet)
return set;
/*
* Instead of delegating calls to the given set copy the low-level values to
* the unmodifiable Subclass
*/
return new UnmodifiableCharArraySet(set.matchVersion, set.entries, set.ignoreCase, set.count);
}
/**
* Returns a copy of the given set as a {@link CharArraySet}. If the given set
* is a {@link CharArraySet} the ignoreCase property will be preserved.
*
* @param set
* a set to copy
* @return a copy of the given set as a {@link CharArraySet}. If the given set
* is a {@link CharArraySet} the ignoreCase and matchVersion property will be
* preserved.
* @deprecated use {@link #copy(Version, Set)} instead.
*/
@Deprecated
public static CharArraySet copy(final Set<?> set) {
if(set == EMPTY_SET)
return EMPTY_SET;
return copy(Version.LUCENE_30, set);
}
/**
* Returns a copy of the given set as a {@link CharArraySet}. If the given set
* is a {@link CharArraySet} the ignoreCase property will be preserved.
* <p>
* <b>Note:</b> If you intend to create a copy of another {@link CharArraySet} where
* the {@link Version} of the source set differs from its copy
* {@link #CharArraySet(Version, Collection, boolean)} should be used instead.
* The {@link #copy(Version, Set)} will preserve the {@link Version} of the
* source set it is an instance of {@link CharArraySet}.
* </p>
*
* @param matchVersion
* compatibility match version see <a href="#version">Version
* note</a> above for details. This argument will be ignored if the
* given set is a {@link CharArraySet}.
* @param set
* a set to copy
* @return a copy of the given set as a {@link CharArraySet}. If the given set
* is a {@link CharArraySet} the ignoreCase property as well as the
* matchVersion will be of the given set will be preserved.
*/
public static CharArraySet copy(final Version matchVersion, final Set<?> set) {
if(set == EMPTY_SET)
return EMPTY_SET;
if(set instanceof CharArraySet) {
final CharArraySet source = (CharArraySet) set;
// use fast path instead of iterating all values
// this is even on very small sets ~10 times faster than iterating
final char[][] entries = new char[source.entries.length][];
System.arraycopy(source.entries, 0, entries, 0, entries.length);
return new CharArraySet(source.matchVersion, entries, source.ignoreCase, source.count);
}
return new CharArraySet(matchVersion, set, false);
}
/** The Iterator<String> for this set. Strings are constructed on the fly, so
* use <code>nextCharArray</code> for more efficient access. */
public class CharArraySetIterator implements Iterator<String> {
int pos=-1;
char[] next;
CharArraySetIterator() {
goNext();
}
private void goNext() {
next = null;
pos++;
while (pos < entries.length && (next=entries[pos]) == null) pos++;
}
public boolean hasNext() {
return next != null;
}
/** do not modify the returned char[] */
public char[] nextCharArray() {
char[] ret = next;
goNext();
return ret;
}
/** Returns the next String, as a Set<String> would...
* use nextCharArray() for better efficiency. */
public String next() {
return new String(nextCharArray());
}
public void remove() {
throw new UnsupportedOperationException();
}
}
/** returns an iterator of new allocated Strings */
public Iterator<String> stringIterator() {
return new CharArraySetIterator();
}
/** returns an iterator of new allocated Strings, this method violates the Set interface */
@Override
@SuppressWarnings("unchecked")
public Iterator<Object> iterator() {
return (Iterator) stringIterator();
}
/**
* Efficient unmodifiable {@link CharArraySet}. This implementation does not
* delegate calls to a give {@link CharArraySet} like
* {@link Collections#unmodifiableSet(java.util.Set)} does. Instead is passes
* the internal representation of a {@link CharArraySet} to a super
* constructor and overrides all mutators.
*/
private static class UnmodifiableCharArraySet extends CharArraySet {
private UnmodifiableCharArraySet(Version matchVersion, char[][] entries, boolean ignoreCase,
int count) {
super(matchVersion, entries, ignoreCase, count);
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public boolean add(Object o){
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection<? extends Object> coll) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(char[] text) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(CharSequence text) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(String text) {
throw new UnsupportedOperationException();
}
}
/**
* Empty {@link UnmodifiableCharArraySet} optimized for speed.
* Contains checks will always return <code>false</code> or throw
* NPE if necessary.
*/
private static final class EmptyCharArraySet extends UnmodifiableCharArraySet {
private EmptyCharArraySet() {
super(Version.LUCENE_CURRENT, new char[0][], false, 0);
}
@Override
public boolean contains(char[] text, int off, int len) {
if(text == null)
throw new NullPointerException();
return false;
}
@Override
public boolean contains(CharSequence cs) {
if(cs == null)
throw new NullPointerException();
return false;
}
@Override
public boolean contains(Object o) {
if(o == null)
throw new NullPointerException();
return false;
}
}
}
|