Lucene example source code file (CharArrayMap.java)
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The Lucene CharArrayMap.java source code
package org.apache.lucene.analysis;
/**
* 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.
*/
import java.util.Arrays;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.util.CharacterUtils;
import org.apache.lucene.util.Version;
/**
* A simple class that stores key 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
* map, nor does it resize its hash table to be smaller,
* etc. It is designed to be quick to retrieve items
* by char[] keys without the necessity of converting
* to a String first.
* <p>You must specify the required {@link Version}
* compatibility when creating {@link CharArrayMap}:
* <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 CharArrayMap} with the behavior before Lucene
* 3.1 pass a {@link Version} < 3.1 to the constructors.
*/
public class CharArrayMap<V> extends AbstractMap {
// private only because missing generics
private static final CharArrayMap<?> EMPTY_MAP = new EmptyCharArrayMap();
private final static int INIT_SIZE = 8;
private final CharacterUtils charUtils;
private boolean ignoreCase;
private int count;
final Version matchVersion; // package private because used in CharArraySet
char[][] keys; // package private because used in CharArraySet's non Set-conform CharArraySetIterator
V[] values; // package private because used in CharArraySet's non Set-conform CharArraySetIterator
/**
* Create map 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 if and only if the set should be case sensitive
* otherwise <code>true.
*/
@SuppressWarnings("unchecked")
public CharArrayMap(Version matchVersion, int startSize, boolean ignoreCase) {
this.ignoreCase = ignoreCase;
int size = INIT_SIZE;
while(startSize + (startSize>>2) > size)
size <<= 1;
keys = new char[size][];
values = (V[]) new Object[size];
this.charUtils = CharacterUtils.getInstance(matchVersion);
this.matchVersion = matchVersion;
}
/**
* Creates a map from the mappings in another map.
*
* @param matchVersion
* compatibility match version see <a href="#version">Version
* note</a> above for details.
* @param c
* a map whose mappings to be copied
* @param ignoreCase
* <code>false if and only if the set should be case sensitive
* otherwise <code>true.
*/
public CharArrayMap(Version matchVersion, Map<?,? extends V> c, boolean ignoreCase) {
this(matchVersion, c.size(), ignoreCase);
putAll(c);
}
/** Create set from the supplied map (used internally for readonly maps...) */
private CharArrayMap(CharArrayMap<V> toCopy){
this.keys = toCopy.keys;
this.values = toCopy.values;
this.ignoreCase = toCopy.ignoreCase;
this.count = toCopy.count;
this.charUtils = toCopy.charUtils;
this.matchVersion = toCopy.matchVersion;
}
/** Clears all entries in this map. This method is supported for reusing, but not {@link Map#remove}. */
@Override
public void clear() {
count = 0;
Arrays.fill(keys, null);
Arrays.fill(values, null);
}
/** true if the <code>len chars of text starting at off
* are in the {@link #keySet} */
public boolean containsKey(char[] text, int off, int len) {
return keys[getSlot(text, off, len)] != null;
}
/** true if the <code>CharSequence is in the {@link #keySet} */
public boolean containsKey(CharSequence cs) {
return keys[getSlot(cs)] != null;
}
@Override
public boolean containsKey(Object o) {
if (o instanceof char[]) {
final char[] text = (char[])o;
return containsKey(text, 0, text.length);
}
return containsKey(o.toString());
}
/** returns the value of the mapping of <code>len chars of text
* starting at <code>off */
public V get(char[] text, int off, int len) {
return values[getSlot(text, off, len)];
}
/** returns the value of the mapping of the chars inside this {@code CharSequence} */
public V get(CharSequence cs) {
return values[getSlot(cs)];
}
@Override
public V get(Object o) {
if (o instanceof char[]) {
final char[] text = (char[])o;
return get(text, 0, text.length);
}
return get(o.toString());
}
private int getSlot(char[] text, int off, int len) {
int code = getHashCode(text, off, len);
int pos = code & (keys.length-1);
char[] text2 = keys[pos];
if (text2 != null && !equals(text, off, len, text2)) {
final int inc = ((code>>8)+code)|1;
do {
code += inc;
pos = code & (keys.length-1);
text2 = keys[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 & (keys.length-1);
char[] text2 = keys[pos];
if (text2 != null && !equals(text, text2)) {
final int inc = ((code>>8)+code)|1;
do {
code += inc;
pos = code & (keys.length-1);
text2 = keys[pos];
} while (text2 != null && !equals(text, text2));
}
return pos;
}
/** Add the given mapping. */
public V put(CharSequence text, V value) {
return put(text.toString(), value); // could be more efficient
}
@Override
public V put(Object o, V value) {
if (o instanceof char[]) {
return put((char[])o, value);
}
return put(o.toString(), value);
}
/** Add the given mapping. */
public V put(String text, V value) {
return put(text.toCharArray(), value);
}
/** Add the given mapping.
* 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 V put(char[] text, V value) {
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 (keys[slot] != null) {
final V oldValue = values[slot];
values[slot] = value;
return oldValue;
}
keys[slot] = text;
values[slot] = value;
count++;
if (count + (count>>2) > keys.length) {
rehash();
}
return null;
}
@SuppressWarnings("unchecked")
private void rehash() {
assert keys.length == values.length;
final int newSize = 2*keys.length;
final char[][] oldkeys = keys;
final V[] oldvalues = values;
keys = new char[newSize][];
values = (V[]) new Object[newSize];
for(int i=0; i<oldkeys.length; i++) {
char[] text = oldkeys[i];
if (text != null) {
// todo: could be faster... no need to compare strings on collision
final int slot = getSlot(text,0,text.length);
keys[slot] = text;
values[slot] = oldvalues[i];
}
}
}
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 int getHashCode(char[] text, int offset, int len) {
if (text == null)
throw new NullPointerException();
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) {
if (text == null)
throw new NullPointerException();
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 V remove(Object key) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
return count;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder("{");
for (Map.Entry<Object,V> entry : entrySet()) {
if (sb.length()>1) sb.append(", ");
sb.append(entry);
}
return sb.append('}').toString();
}
private EntrySet entrySet = null;
private CharArraySet keySet = null;
EntrySet createEntrySet() {
return new EntrySet(true);
}
@Override
public final EntrySet entrySet() {
if (entrySet == null) {
entrySet = createEntrySet();
}
return entrySet;
}
// helper for CharArraySet to not produce endless recursion
final Set<Object> originalKeySet() {
return super.keySet();
}
/** Returns an {@link CharArraySet} view on the map's keys.
* The set will use the same {@code matchVersion} as this map. */
@Override @SuppressWarnings("unchecked")
public final CharArraySet keySet() {
if (keySet == null) {
// prevent adding of entries
keySet = new CharArraySet((CharArrayMap) this) {
@Override
public boolean add(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(CharSequence text) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(String text) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(char[] text) {
throw new UnsupportedOperationException();
}
};
}
return keySet;
}
/** public iterator class so efficient methods are exposed to users */
public class EntryIterator implements Iterator<Map.Entry {
private int pos=-1;
private int lastPos;
private final boolean allowModify;
private EntryIterator(boolean allowModify) {
this.allowModify = allowModify;
goNext();
}
private void goNext() {
lastPos = pos;
pos++;
while (pos < keys.length && keys[pos] == null) pos++;
}
public boolean hasNext() {
return pos < keys.length;
}
/** gets the next key... do not modify the returned char[] */
public char[] nextKey() {
goNext();
return keys[lastPos];
}
/** gets the next key as a newly created String object */
public String nextKeyString() {
return new String(nextKey());
}
/** returns the value associated with the last key returned */
public V currentValue() {
return values[lastPos];
}
/** sets the value associated with the last key returned */
public V setValue(V value) {
if (!allowModify)
throw new UnsupportedOperationException();
V old = values[lastPos];
values[lastPos] = value;
return old;
}
/** use nextCharArray() + currentValue() for better efficiency. */
public Map.Entry<Object,V> next() {
goNext();
return new MapEntry(lastPos, allowModify);
}
public void remove() {
throw new UnsupportedOperationException();
}
}
private final class MapEntry implements Map.Entry<Object,V> {
private final int pos;
private final boolean allowModify;
private MapEntry(int pos, boolean allowModify) {
this.pos = pos;
this.allowModify = allowModify;
}
public Object getKey() {
// we must clone here, as putAll to another CharArrayMap
// with other case sensitivity flag would corrupt the keys
return keys[pos].clone();
}
public V getValue() {
return values[pos];
}
public V setValue(V value) {
if (!allowModify)
throw new UnsupportedOperationException();
final V old = values[pos];
values[pos] = value;
return old;
}
@Override
public String toString() {
return new StringBuilder().append(keys[pos]).append('=')
.append((values[pos] == CharArrayMap.this) ? "(this Map)" : values[pos])
.toString();
}
}
/** public EntrySet class so efficient methods are exposed to users */
public final class EntrySet extends AbstractSet<Map.Entry {
private final boolean allowModify;
private EntrySet(boolean allowModify) {
this.allowModify = allowModify;
}
@Override
public EntryIterator iterator() {
return new EntryIterator(allowModify);
}
@Override
public boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
final Map.Entry e = (Map.Entry)o;
final Object key = e.getKey();
final Object val = e.getValue();
final Object v = get(key);
return v == null ? val == null : v.equals(val);
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
return count;
}
@Override
public void clear() {
if (!allowModify)
throw new UnsupportedOperationException();
CharArrayMap.this.clear();
}
}
/**
* Returns an unmodifiable {@link CharArrayMap}. This allows to provide
* unmodifiable views of internal map for "read-only" use.
*
* @param map
* a map for which the unmodifiable map is returned.
* @return an new unmodifiable {@link CharArrayMap}.
* @throws NullPointerException
* if the given map is <code>null.
*/
public static <V> CharArrayMap unmodifiableMap(CharArrayMap map) {
if (map == null)
throw new NullPointerException("Given map is null");
if (map == emptyMap() || map.isEmpty())
return emptyMap();
if (map instanceof UnmodifiableCharArrayMap)
return map;
return new UnmodifiableCharArrayMap<V>(map);
}
/**
* Returns a copy of the given map as a {@link CharArrayMap}. If the given map
* is a {@link CharArrayMap} the ignoreCase property will be preserved.
* <p>
* <b>Note: If you intend to create a copy of another {@link CharArrayMap} where
* the {@link Version} of the source map differs from its copy
* {@link #CharArrayMap(Version, Map, boolean)} should be used instead.
* The {@link #copy(Version, Map)} will preserve the {@link Version} of the
* source map it is an instance of {@link CharArrayMap}.
* </p>
*
* @param matchVersion
* compatibility match version see <a href="#version">Version
* note</a> above for details. This argument will be ignored if the
* given map is a {@link CharArrayMap}.
* @param map
* a map to copy
* @return a copy of the given map as a {@link CharArrayMap}. If the given map
* is a {@link CharArrayMap} the ignoreCase property as well as the
* matchVersion will be of the given map will be preserved.
*/
@SuppressWarnings("unchecked")
public static <V> CharArrayMap copy(final Version matchVersion, final Map map) {
if(map == EMPTY_MAP)
return emptyMap();
if(map instanceof CharArrayMap) {
CharArrayMap<V> m = (CharArrayMap) map;
// use fast path instead of iterating all values
// this is even on very small sets ~10 times faster than iterating
final char[][] keys = new char[m.keys.length][];
System.arraycopy(m.keys, 0, keys, 0, keys.length);
final V[] values = (V[]) new Object[m.values.length];
System.arraycopy(m.values, 0, values, 0, values.length);
m = new CharArrayMap<V>(m);
m.keys = keys;
m.values = values;
return m;
}
return new CharArrayMap<V>(matchVersion, map, false);
}
/** Returns an empty, unmodifiable map. */
@SuppressWarnings("unchecked")
public static <V> CharArrayMap emptyMap() {
return (CharArrayMap<V>) EMPTY_MAP;
}
// package private CharArraySet instanceof check in CharArraySet
static class UnmodifiableCharArrayMap<V> extends CharArrayMap {
UnmodifiableCharArrayMap(CharArrayMap<V> map) {
super(map);
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public V put(Object o, V val){
throw new UnsupportedOperationException();
}
@Override
public V put(char[] text, V val) {
throw new UnsupportedOperationException();
}
@Override
public V put(CharSequence text, V val) {
throw new UnsupportedOperationException();
}
@Override
public V put(String text, V val) {
throw new UnsupportedOperationException();
}
@Override
public V remove(Object key) {
throw new UnsupportedOperationException();
}
@Override
EntrySet createEntrySet() {
return new EntrySet(false);
}
}
/**
* Empty {@link UnmodifiableCharArrayMap} optimized for speed.
* Contains checks will always return <code>false or throw
* NPE if necessary.
*/
private static final class EmptyCharArrayMap<V> extends UnmodifiableCharArrayMap {
EmptyCharArrayMap() {
super(new CharArrayMap<V>(Version.LUCENE_CURRENT, 0, false));
}
@Override
public boolean containsKey(char[] text, int off, int len) {
if(text == null)
throw new NullPointerException();
return false;
}
@Override
public boolean containsKey(CharSequence cs) {
if(cs == null)
throw new NullPointerException();
return false;
}
@Override
public boolean containsKey(Object o) {
if(o == null)
throw new NullPointerException();
return false;
}
@Override
public V get(char[] text, int off, int len) {
if(text == null)
throw new NullPointerException();
return null;
}
@Override
public V get(CharSequence cs) {
if(cs == null)
throw new NullPointerException();
return null;
}
@Override
public V get(Object o) {
if(o == null)
throw new NullPointerException();
return null;
}
}
}
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