| package org.apache.lucene.facet.taxonomy.writercache; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.OutputStream; |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /* |
| * 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. |
| */ |
| |
| /** |
| * Similar to {@link StringBuilder}, but with a more efficient growing strategy. |
| * This class uses char array blocks to grow. |
| * |
| * @lucene.experimental |
| */ |
| class CharBlockArray implements Appendable, Serializable, CharSequence { |
| |
| private static final long serialVersionUID = 1L; |
| |
| private final static int DefaultBlockSize = 32 * 1024; // 32 KB default size |
| |
| final static class Block implements Serializable, Cloneable { |
| private static final long serialVersionUID = 1L; |
| |
| final char[] chars; |
| int length; |
| |
| Block(int size) { |
| this.chars = new char[size]; |
| this.length = 0; |
| } |
| } |
| |
| List<Block> blocks; |
| Block current; |
| int blockSize; |
| int length; |
| |
| CharBlockArray() { |
| this(DefaultBlockSize); |
| } |
| |
| CharBlockArray(int blockSize) { |
| this.blocks = new ArrayList<Block>(); |
| this.blockSize = blockSize; |
| addBlock(); |
| } |
| |
| private void addBlock() { |
| this.current = new Block(this.blockSize); |
| this.blocks.add(this.current); |
| } |
| |
| int blockIndex(int index) { |
| return index / blockSize; |
| } |
| |
| int indexInBlock(int index) { |
| return index % blockSize; |
| } |
| |
| @Override |
| public CharBlockArray append(CharSequence chars) { |
| return append(chars, 0, chars.length()); |
| } |
| |
| @Override |
| public CharBlockArray append(char c) { |
| if (this.current.length == this.blockSize) { |
| addBlock(); |
| } |
| this.current.chars[this.current.length++] = c; |
| this.length++; |
| |
| return this; |
| } |
| |
| @Override |
| public CharBlockArray append(CharSequence chars, int start, int length) { |
| int end = start + length; |
| for (int i = start; i < end; i++) { |
| append(chars.charAt(i)); |
| } |
| return this; |
| } |
| |
| public CharBlockArray append(char[] chars, int start, int length) { |
| int offset = start; |
| int remain = length; |
| while (remain > 0) { |
| if (this.current.length == this.blockSize) { |
| addBlock(); |
| } |
| int toCopy = remain; |
| int remainingInBlock = this.blockSize - this.current.length; |
| if (remainingInBlock < toCopy) { |
| toCopy = remainingInBlock; |
| } |
| System.arraycopy(chars, offset, this.current.chars, this.current.length, toCopy); |
| offset += toCopy; |
| remain -= toCopy; |
| this.current.length += toCopy; |
| } |
| |
| this.length += length; |
| return this; |
| } |
| |
| public CharBlockArray append(String s) { |
| int remain = s.length(); |
| int offset = 0; |
| while (remain > 0) { |
| if (this.current.length == this.blockSize) { |
| addBlock(); |
| } |
| int toCopy = remain; |
| int remainingInBlock = this.blockSize - this.current.length; |
| if (remainingInBlock < toCopy) { |
| toCopy = remainingInBlock; |
| } |
| s.getChars(offset, offset + toCopy, this.current.chars, this.current.length); |
| offset += toCopy; |
| remain -= toCopy; |
| this.current.length += toCopy; |
| } |
| |
| this.length += s.length(); |
| return this; |
| } |
| |
| @Override |
| public char charAt(int index) { |
| Block b = blocks.get(blockIndex(index)); |
| return b.chars[indexInBlock(index)]; |
| } |
| |
| @Override |
| public int length() { |
| return this.length; |
| } |
| |
| @Override |
| public CharSequence subSequence(int start, int end) { |
| int remaining = end - start; |
| StringBuilder sb = new StringBuilder(remaining); |
| int blockIdx = blockIndex(start); |
| int indexInBlock = indexInBlock(start); |
| while (remaining > 0) { |
| Block b = blocks.get(blockIdx++); |
| int numToAppend = Math.min(remaining, b.length - indexInBlock); |
| sb.append(b.chars, indexInBlock, numToAppend); |
| remaining -= numToAppend; |
| indexInBlock = 0; // 2nd+ iterations read from start of the block |
| } |
| return sb.toString(); |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder sb = new StringBuilder(); |
| for (Block b : blocks) { |
| sb.append(b.chars, 0, b.length); |
| } |
| return sb.toString(); |
| } |
| |
| void flush(OutputStream out) throws IOException { |
| ObjectOutputStream oos = null; |
| try { |
| oos = new ObjectOutputStream(out); |
| oos.writeObject(this); |
| oos.flush(); |
| } finally { |
| if (oos != null) { |
| oos.close(); |
| } |
| } |
| } |
| |
| public static CharBlockArray open(InputStream in) throws IOException, ClassNotFoundException { |
| ObjectInputStream ois = null; |
| try { |
| ois = new ObjectInputStream(in); |
| CharBlockArray a = (CharBlockArray) ois.readObject(); |
| return a; |
| } finally { |
| if (ois != null) { |
| ois.close(); |
| } |
| } |
| } |
| |
| } |