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.io.IOException;
import java.io.Reader;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.CharacterUtils;
import org.apache.lucene.util.Version;
import org.apache.lucene.util.VirtualMethod;
import org.apache.lucene.util.CharacterUtils.CharacterBuffer;
/**
* An abstract base class for simple, character-oriented tokenizers.
* <p>
* <a name="version">You must specify the required {@link Version} compatibility
* when creating {@link CharTokenizer}:
* <ul>
* <li>As of 3.1, {@link CharTokenizer} uses an int based API to normalize and
* detect token codepoints. See {@link #isTokenChar(int)} and
* {@link #normalize(int)} for details.</li>
* </ul>
* <p>
* A new {@link CharTokenizer} API has been introduced with Lucene 3.1. This API
* moved from UTF-16 code units to UTF-32 codepoints to eventually add support
* for <a href=
* "http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Character.html#supplementary"
* >supplementary characters</a>. The old <i>char</i> based API has been
* deprecated and should be replaced with the <i>int</i> based methods
* {@link #isTokenChar(int)} and {@link #normalize(int)}.
* </p>
* <p>
* As of Lucene 3.1 each {@link CharTokenizer} - constructor expects a
* {@link Version} argument. Based on the given {@link Version} either the new
* API or a backwards compatibility layer is used at runtime. For
* {@link Version} < 3.1 the backwards compatibility layer ensures correct
* behavior even for indexes build with previous versions of Lucene. If a
* {@link Version} >= 3.1 is used {@link CharTokenizer} requires the new API to
* be implemented by the instantiated class. Yet, the old <i>char</i> based API
* is not required anymore even if backwards compatibility must be preserved.
* {@link CharTokenizer} subclasses implementing the new API are fully backwards
* compatible if instantiated with {@link Version} < 3.1.
* </p>
* <p>
* <strong>Note:</strong> If you use a subclass of {@link CharTokenizer} with {@link Version} >=
* 3.1 on an index build with a version < 3.1, created tokens might not be
* compatible with the terms in your index.
* </p>
**/
public abstract class CharTokenizer extends Tokenizer {
/**
* Creates a new {@link CharTokenizer} instance
*
* @param matchVersion
* Lucene version to match See {@link <a href="#version">above</a>}
* @param input
* the input to split up into tokens
*/
public CharTokenizer(Version matchVersion, Reader input) {
super(input);
charUtils = CharacterUtils.getInstance(matchVersion);
useOldAPI = useOldAPI(matchVersion);
}
/**
* Creates a new {@link CharTokenizer} instance
*
* @param matchVersion
* Lucene version to match See {@link <a href="#version">above</a>}
* @param source
* the attribute source to use for this {@link Tokenizer}
* @param input
* the input to split up into tokens
*/
public CharTokenizer(Version matchVersion, AttributeSource source,
Reader input) {
super(source, input);
charUtils = CharacterUtils.getInstance(matchVersion);
useOldAPI = useOldAPI(matchVersion);
}
/**
* Creates a new {@link CharTokenizer} instance
*
* @param matchVersion
* Lucene version to match See {@link <a href="#version">above</a>}
* @param factory
* the attribute factory to use for this {@link Tokenizer}
* @param input
* the input to split up into tokens
*/
public CharTokenizer(Version matchVersion, AttributeFactory factory,
Reader input) {
super(factory, input);
charUtils = CharacterUtils.getInstance(matchVersion);
useOldAPI = useOldAPI(matchVersion);
}
/**
* Creates a new {@link CharTokenizer} instance
* @param input the input to split up into tokens
* @deprecated use {@link #CharTokenizer(Version, Reader)} instead. This will be
* removed in Lucene 4.0.
*/
@Deprecated
public CharTokenizer(Reader input) {
this(Version.LUCENE_30, input);
}
/**
* Creates a new {@link CharTokenizer} instance
* @param input the input to split up into tokens
* @param source the attribute source to use for this {@link Tokenizer}
* @deprecated use {@link #CharTokenizer(Version, AttributeSource, Reader)} instead. This will be
* removed in Lucene 4.0.
*/
@Deprecated
public CharTokenizer(AttributeSource source, Reader input) {
this(Version.LUCENE_30, source, input);
}
/**
* Creates a new {@link CharTokenizer} instance
* @param input the input to split up into tokens
* @param factory the attribute factory to use for this {@link Tokenizer}
* @deprecated use {@link #CharTokenizer(Version, AttributeSource.AttributeFactory, Reader)} instead. This will be
* removed in Lucene 4.0.
*/
@Deprecated
public CharTokenizer(AttributeFactory factory, Reader input) {
this(Version.LUCENE_30, factory, input);
}
private int offset = 0, bufferIndex = 0, dataLen = 0, finalOffset = 0;
private static final int MAX_WORD_LEN = 255;
private static final int IO_BUFFER_SIZE = 4096;
private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);;
private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
private final CharacterUtils charUtils;
private final CharacterBuffer ioBuffer = CharacterUtils.newCharacterBuffer(IO_BUFFER_SIZE);
/**
* @deprecated this will be removed in lucene 4.0
*/
@Deprecated
private final boolean useOldAPI;
/**
* @deprecated this will be removed in lucene 4.0
*/
@Deprecated
private static final VirtualMethod<CharTokenizer> isTokenCharMethod =
new VirtualMethod<CharTokenizer>(CharTokenizer.class, "isTokenChar", char.class);
/**
* @deprecated this will be removed in lucene 4.0
*/
@Deprecated
private static final VirtualMethod<CharTokenizer> normalizeMethod =
new VirtualMethod<CharTokenizer>(CharTokenizer.class, "normalize", char.class);
/**
* Returns true iff a UTF-16 code unit should be included in a token. This
* tokenizer generates as tokens adjacent sequences of characters which
* satisfy this predicate. Characters for which this is <code>false</code> are
* used to define token boundaries and are not included in tokens.
* <p>
* Note: This method cannot handle <a href=
* "http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Character.html#supplementary"
* >supplementary characters</a>. To support all Unicode characters, including
* supplementary characters, use the {@link #isTokenChar(int)} method.
* </p>
*
* @deprecated use {@link #isTokenChar(int)} instead. This method will be
* removed in Lucene 4.0.
*/
@Deprecated
protected boolean isTokenChar(char c) {
return isTokenChar((int)c);
}
/**
* Called on each token UTF-16 code unit to normalize it before it is added to the
* token. The default implementation does nothing. Subclasses may use this to,
* e.g., lowercase tokens.
* <p>
* Note: This method cannot handle <a href=
* "http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Character.html#supplementary"
* >supplementary characters</a>. To support all Unicode characters, including
* supplementary characters, use the {@link #normalize(int)} method.
* </p>
*
* @deprecated use {@link #normalize(int)} instead. This method will be
* removed in Lucene 4.0.
*/
@Deprecated
protected char normalize(char c) {
return (char) normalize((int) c);
}
/**
* Returns true iff a codepoint should be included in a token. This tokenizer
* generates as tokens adjacent sequences of codepoints which satisfy this
* predicate. Codepoints for which this is false are used to define token
* boundaries and are not included in tokens.
* <p>
* As of Lucene 3.1 the char based API ({@link #isTokenChar(char)} and
* {@link #normalize(char)}) has been depreciated in favor of a Unicode 4.0
* compatible int based API to support codepoints instead of UTF-16 code
* units. Subclasses of {@link CharTokenizer} must not override the char based
* methods if a {@link Version} >= 3.1 is passed to the constructor.
* <p>
* <p>
* NOTE: This method will be marked <i>abstract</i> in Lucene 4.0.
* </p>
*/
protected boolean isTokenChar(int c) {
throw new UnsupportedOperationException("since LUCENE_31 subclasses of CharTokenizer must implement isTokenChar(int)");
}
/**
* Called on each token character to normalize it before it is added to the
* token. The default implementation does nothing. Subclasses may use this to,
* e.g., lowercase tokens.
* <p>
* As of Lucene 3.1 the char based API ({@link #isTokenChar(char)} and
* {@link #normalize(char)}) has been depreciated in favor of a Unicode 4.0
* compatible int based API to support codepoints instead of UTF-16 code
* units. Subclasses of {@link CharTokenizer} must not override the char based
* methods if a {@link Version} >= 3.1 is passed to the constructor.
* <p>
* <p>
* NOTE: This method will be marked <i>abstract</i> in Lucene 4.0.
* </p>
*/
protected int normalize(int c) {
return c;
}
@Override
public final boolean incrementToken() throws IOException {
clearAttributes();
if(useOldAPI) // TODO remove this in LUCENE 4.0
return incrementTokenOld();
int length = 0;
int start = -1; // this variable is always initialized
char[] buffer = termAtt.buffer();
while (true) {
if (bufferIndex >= dataLen) {
offset += dataLen;
if(!charUtils.fill(ioBuffer, input)) { // read supplementary char aware with CharacterUtils
dataLen = 0; // so next offset += dataLen won't decrement offset
if (length > 0) {
break;
} else {
finalOffset = correctOffset(offset);
return false;
}
}
dataLen = ioBuffer.getLength();
bufferIndex = 0;
}
// use CharacterUtils here to support < 3.1 UTF-16 code unit behavior if the char based methods are gone
final int c = charUtils.codePointAt(ioBuffer.getBuffer(), bufferIndex);
bufferIndex += Character.charCount(c);
if (isTokenChar(c)) { // if it's a token char
if (length == 0) { // start of token
assert start == -1;
start = offset + bufferIndex - 1;
} else if (length >= buffer.length-1) { // check if a supplementary could run out of bounds
buffer = termAtt.resizeBuffer(2+length); // make sure a supplementary fits in the buffer
}
length += Character.toChars(normalize(c), buffer, length); // buffer it, normalized
if (length >= MAX_WORD_LEN) // buffer overflow! make sure to check for >= surrogate pair could break == test
break;
} else if (length > 0) // at non-Letter w/ chars
break; // return 'em
}
termAtt.setLength(length);
assert start != -1;
offsetAtt.setOffset(correctOffset(start), finalOffset = correctOffset(start+length));
return true;
}
/**
* The <= 3.0 version of incrementToken. This is a backwards compat implementation used
* if a version <= 3.0 is provided to the ctor.
* @deprecated remove in 4.0
*/
@Deprecated
private boolean incrementTokenOld() throws IOException {
int length = 0;
int start = -1; // this variable is always initialized
char[] buffer = termAtt.buffer();
final char[] oldIoBuffer = ioBuffer.getBuffer();
while (true) {
if (bufferIndex >= dataLen) {
offset += dataLen;
dataLen = input.read(oldIoBuffer);
if (dataLen == -1) {
dataLen = 0; // so next offset += dataLen won't decrement offset
if (length > 0) {
break;
} else {
finalOffset = correctOffset(offset);
return false;
}
}
bufferIndex = 0;
}
final char c = oldIoBuffer[bufferIndex++];
if (isTokenChar(c)) { // if it's a token char
if (length == 0) { // start of token
assert start == -1;
start = offset + bufferIndex - 1;
} else if (length == buffer.length) {
buffer = termAtt.resizeBuffer(1+length);
}
buffer[length++] = normalize(c); // buffer it, normalized
if (length == MAX_WORD_LEN) // buffer overflow!
break;
} else if (length > 0) // at non-Letter w/ chars
break; // return 'em
}
termAtt.setLength(length);
assert start != -1;
offsetAtt.setOffset(correctOffset(start), correctOffset(start+length));
return true;
}
@Override
public final void end() {
// set final offset
offsetAtt.setOffset(finalOffset, finalOffset);
}
@Override
public void reset(Reader input) throws IOException {
super.reset(input);
bufferIndex = 0;
offset = 0;
dataLen = 0;
finalOffset = 0;
ioBuffer.reset(); // make sure to reset the IO buffer!!
}
/**
* @deprecated this will be removed in lucene 4.0
*/
@Deprecated
private boolean useOldAPI(Version matchVersion) {
final Class<? extends CharTokenizer> clazz = this.getClass();
if (matchVersion.onOrAfter(Version.LUCENE_31)
&& (isTokenCharMethod.isOverriddenAsOf(clazz) || normalizeMethod
.isOverriddenAsOf(clazz))) throw new IllegalArgumentException(
"For matchVersion >= LUCENE_31, CharTokenizer subclasses must not override isTokenChar(char) or normalize(char).");
return !matchVersion.onOrAfter(Version.LUCENE_31);
}
}