- /*
- * Copyright 2002,2004 The Apache Software Foundation
- *
- * Licensed 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"/></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 final 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 final void setTablength(final int tabLength) {
- this.tabLength = tabLength;
- }
-
- /**
- * Returns the tab length.
- *
- * @return the number of spaces used when converting a tab
- */
- private final 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 final 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 final 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;
- }
- }
- }
- }
- }
- }