| /* |
| * 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 |
| * |
| * https://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. |
| * |
| */ |
| package org.apache.tools.ant.filters; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| import org.apache.tools.ant.types.Parameter; |
| |
| /** |
| * Converts tabs to spaces. |
| * |
| * Example: |
| * |
| * <pre><tabstospaces tablength="8"/></pre> |
| * |
| * Or: |
| * |
| * <pre><filterreader classname="org.apache.tools.ant.filters.TabsToSpaces"> |
| * <param name="tablength" value="8"/> |
| * </filterreader></pre> |
| * |
| */ |
| public final class TabsToSpaces |
| extends BaseParamFilterReader |
| implements ChainableReader { |
| /** The default tab length. */ |
| private static final int DEFAULT_TAB_LENGTH = 8; |
| |
| /** Parameter name for the length of a tab. */ |
| private static final String TAB_LENGTH_KEY = "tablength"; |
| |
| /** Tab length in this filter. */ |
| private int tabLength = DEFAULT_TAB_LENGTH; |
| |
| /** The number of spaces still to be read to represent the last-read tab. */ |
| private int spacesRemaining = 0; |
| |
| /** |
| * Constructor for "dummy" instances. |
| * |
| * @see BaseFilterReader#BaseFilterReader() |
| */ |
| public TabsToSpaces() { |
| super(); |
| } |
| |
| /** |
| * Creates a new filtered reader. |
| * |
| * @param in A Reader object providing the underlying stream. |
| * Must not be <code>null</code>. |
| */ |
| public TabsToSpaces(final Reader in) { |
| super(in); |
| } |
| |
| /** |
| * Returns the next character in the filtered stream, converting tabs |
| * to the specified number of spaces. |
| * |
| * @return the next character in the resulting stream, or -1 |
| * if the end of the resulting stream has been reached |
| * |
| * @exception IOException if the underlying stream throws an IOException |
| * during reading |
| */ |
| public int read() throws IOException { |
| if (!getInitialized()) { |
| initialize(); |
| setInitialized(true); |
| } |
| |
| int ch = -1; |
| |
| if (spacesRemaining > 0) { |
| spacesRemaining--; |
| ch = ' '; |
| } else { |
| ch = in.read(); |
| if (ch == '\t') { |
| spacesRemaining = tabLength - 1; |
| ch = ' '; |
| } |
| } |
| return ch; |
| } |
| |
| /** |
| * Sets the tab length. |
| * |
| * @param tabLength the number of spaces to be used when converting a tab. |
| */ |
| public void setTablength(final int tabLength) { |
| this.tabLength = tabLength; |
| } |
| |
| /** |
| * Returns the tab length. |
| * |
| * @return the number of spaces used when converting a tab |
| */ |
| private int getTablength() { |
| return tabLength; |
| } |
| |
| /** |
| * Creates a new TabsToSpaces using the passed in |
| * Reader for instantiation. |
| * |
| * @param rdr A Reader object providing the underlying stream. |
| * Must not be <code>null</code>. |
| * |
| * @return a new filter based on this configuration, but filtering |
| * the specified reader |
| */ |
| public Reader chain(final Reader rdr) { |
| TabsToSpaces newFilter = new TabsToSpaces(rdr); |
| newFilter.setTablength(getTablength()); |
| newFilter.setInitialized(true); |
| return newFilter; |
| } |
| |
| /** |
| * Parses the parameters to set the tab length. |
| */ |
| private void initialize() { |
| Parameter[] params = getParameters(); |
| if (params != null) { |
| for (Parameter param : params) { |
| if (param != null) { |
| if (TAB_LENGTH_KEY.equals(param.getName())) { |
| tabLength = Integer.parseInt(param.getValue()); |
| break; |
| } |
| } |
| } |
| } |
| } |
| } |