package org.apache.lucene.analysis.tokenattributes;
/**
* 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.Serializable;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.AttributeImpl;
/**
* The term text of a Token.
*/
public class TermAttributeImpl extends AttributeImpl implements TermAttribute, Cloneable, Serializable {
private static int MIN_BUFFER_SIZE = 10;
private char[] termBuffer;
private int termLength;
/** Returns the Token's term text.
*
* This method has a performance penalty
* because the text is stored internally in a char[]. If
* possible, use {@link #termBuffer()} and {@link
* #termLength()} directly instead. If you really need a
* String, use this method, which is nothing more than
* a convenience call to <b>new String(token.termBuffer(), 0, token.termLength())</b>
*/
public String term() {
initTermBuffer();
return new String(termBuffer, 0, termLength);
}
/** Copies the contents of buffer, starting at offset for
* length characters, into the termBuffer array.
* @param buffer the buffer to copy
* @param offset the index in the buffer of the first character to copy
* @param length the number of characters to copy
*/
public void setTermBuffer(char[] buffer, int offset, int length) {
growTermBuffer(length);
System.arraycopy(buffer, offset, termBuffer, 0, length);
termLength = length;
}
/** Copies the contents of buffer into the termBuffer array.
* @param buffer the buffer to copy
*/
public void setTermBuffer(String buffer) {
int length = buffer.length();
growTermBuffer(length);
buffer.getChars(0, length, termBuffer, 0);
termLength = length;
}
/** Copies the contents of buffer, starting at offset and continuing
* for length characters, into the termBuffer array.
* @param buffer the buffer to copy
* @param offset the index in the buffer of the first character to copy
* @param length the number of characters to copy
*/
public void setTermBuffer(String buffer, int offset, int length) {
assert offset <= buffer.length();
assert offset + length <= buffer.length();
growTermBuffer(length);
buffer.getChars(offset, offset + length, termBuffer, 0);
termLength = length;
}
/** Returns the internal termBuffer character array which
* you can then directly alter. If the array is too
* small for your token, use {@link
* #resizeTermBuffer(int)} to increase it. After
* altering the buffer be sure to call {@link
* #setTermLength} to record the number of valid
* characters that were placed into the termBuffer. */
public char[] termBuffer() {
initTermBuffer();
return termBuffer;
}
/** Grows the termBuffer to at least size newSize, preserving the
* existing content. Note: If the next operation is to change
* the contents of the term buffer use
* {@link #setTermBuffer(char[], int, int)},
* {@link #setTermBuffer(String)}, or
* {@link #setTermBuffer(String, int, int)}
* to optimally combine the resize with the setting of the termBuffer.
* @param newSize minimum size of the new termBuffer
* @return newly created termBuffer with length >= newSize
*/
public char[] resizeTermBuffer(int newSize) {
if (termBuffer == null) {
// The buffer is always at least MIN_BUFFER_SIZE
termBuffer = new char[ArrayUtil.getNextSize(newSize < MIN_BUFFER_SIZE ? MIN_BUFFER_SIZE : newSize)];
} else {
if(termBuffer.length < newSize){
// Not big enough; create a new array with slight
// over allocation and preserve content
final char[] newCharBuffer = new char[ArrayUtil.getNextSize(newSize)];
System.arraycopy(termBuffer, 0, newCharBuffer, 0, termBuffer.length);
termBuffer = newCharBuffer;
}
}
return termBuffer;
}
/** Allocates a buffer char[] of at least newSize, without preserving the existing content.
* its always used in places that set the content
* @param newSize minimum size of the buffer
*/
private void growTermBuffer(int newSize) {
if (termBuffer == null) {
// The buffer is always at least MIN_BUFFER_SIZE
termBuffer = new char[ArrayUtil.getNextSize(newSize < MIN_BUFFER_SIZE ? MIN_BUFFER_SIZE : newSize)];
} else {
if(termBuffer.length < newSize){
// Not big enough; create a new array with slight
// over allocation:
termBuffer = new char[ArrayUtil.getNextSize(newSize)];
}
}
}
private void initTermBuffer() {
if (termBuffer == null) {
termBuffer = new char[ArrayUtil.getNextSize(MIN_BUFFER_SIZE)];
termLength = 0;
}
}
/** Return number of valid characters (length of the term)
* in the termBuffer array. */
public int termLength() {
return termLength;
}
/** Set number of valid characters (length of the term) in
* the termBuffer array. Use this to truncate the termBuffer
* or to synchronize with external manipulation of the termBuffer.
* Note: to grow the size of the array,
* use {@link #resizeTermBuffer(int)} first.
* @param length the truncated length
*/
public void setTermLength(int length) {
initTermBuffer();
if (length > termBuffer.length)
throw new IllegalArgumentException("length " + length + " exceeds the size of the termBuffer (" + termBuffer.length + ")");
termLength = length;
}
@Override
public int hashCode() {
initTermBuffer();
int code = termLength;
code = code * 31 + ArrayUtil.hashCode(termBuffer, 0, termLength);
return code;
}
@Override
public void clear() {
termLength = 0;
}
@Override
public Object clone() {
TermAttributeImpl t = (TermAttributeImpl)super.clone();
// Do a deep clone
if (termBuffer != null) {
t.termBuffer = new char[this.termLength];
System.arraycopy(this.termBuffer, 0, t.termBuffer, 0, this.termLength);
}
return t;
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (other instanceof TermAttribute) {
initTermBuffer();
TermAttributeImpl o = ((TermAttributeImpl) other);
o.initTermBuffer();
if (termLength != o.termLength)
return false;
for(int i=0;i<termLength;i++) {
if (termBuffer[i] != o.termBuffer[i]) {
return false;
}
}
return true;
}
return false;
}
@Override
public String toString() {
initTermBuffer();
return "term=" + new String(termBuffer, 0, termLength);
}
@Override
public void copyTo(AttributeImpl target) {
initTermBuffer();
TermAttribute t = (TermAttribute) target;
t.setTermBuffer(termBuffer, 0, termLength);
}
}