Ant example source code file (TabsToSpaces.java)

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Java - Ant tags/keywords

baseparamfilterreader, chainablereader, default_tab_length, default_tab_length, io, ioexception, ioexception, parameter, reader, reader, string, tab_length_key, tabstospaces, tabstospaces

The TabsToSpaces.java source code

/*
 *  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.
 *
 */
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><tabtospaces tablength="8"/>

* * 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. */ 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. * * @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 (int i = 0; i < params.length; i++) { if (params[i] != null) { if (TAB_LENGTH_KEY.equals(params[i].getName())) { tabLength = new Integer(params[i].getValue()).intValue(); break; } } } } } }