001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2015 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.header;
021
022import java.io.BufferedInputStream;
023import java.io.IOException;
024import java.io.InputStreamReader;
025import java.io.LineNumberReader;
026import java.io.Reader;
027import java.io.StringReader;
028import java.io.UnsupportedEncodingException;
029import java.net.URI;
030import java.nio.charset.Charset;
031import java.util.List;
032import java.util.regex.Pattern;
033
034import org.apache.commons.beanutils.ConversionException;
035import org.apache.commons.lang3.StringUtils;
036
037import com.google.common.collect.ImmutableList;
038import com.google.common.collect.Lists;
039import com.google.common.io.Closeables;
040import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
041import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
042import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
043
044/**
045 * Abstract super class for header checks.
046 * Provides support for header and headerFile properties.
047 * @author o_sukhosolsky
048 */
049public abstract class AbstractHeaderCheck extends AbstractFileSetCheck {
050    /** Pattern to detect occurrences of '\n' in text. */
051    private static final Pattern ESCAPED_LINE_FEED_PATTERN = Pattern.compile("\\\\n");
052    /** The file that contains the header to check against. */
053    private String headerFile;
054
055    /** Name of a charset to use for loading the header from a file. */
056    private String charset = System.getProperty("file.encoding", "UTF-8");
057
058    /** The lines of the header file. */
059    private final List<String> readerLines = Lists.newArrayList();
060
061    /**
062     * Hook method for post processing header lines.
063     * This implementation does nothing.
064     */
065    protected abstract void postProcessHeaderLines();
066
067    /**
068     * Return the header lines to check against.
069     * @return the header lines to check against.
070     */
071    protected ImmutableList<String> getHeaderLines() {
072        return ImmutableList.copyOf(readerLines);
073    }
074
075    /**
076     * Set the charset to use for loading the header from a file.
077     * @param charset the charset to use for loading the header from a file
078     * @throws UnsupportedEncodingException if charset is unsupported
079     */
080    public void setCharset(String charset) throws UnsupportedEncodingException {
081        if (!Charset.isSupported(charset)) {
082            final String message = "unsupported charset: '" + charset + "'";
083            throw new UnsupportedEncodingException(message);
084        }
085        this.charset = charset;
086    }
087
088    /**
089     * Set the header file to check against.
090     * @param fileName the file that contains the header to check against.
091     * @throws CheckstyleException if fileName is empty.
092     */
093    public void setHeaderFile(String fileName) throws CheckstyleException {
094        if (StringUtils.isBlank(fileName)) {
095            throw new CheckstyleException(
096                "property 'headerFile' is missing or invalid in module "
097                    + getConfiguration().getName());
098        }
099
100        headerFile = fileName;
101    }
102
103    /**
104     * Load the header from a file.
105     * @throws CheckstyleException if the file cannot be loaded
106     */
107    private void loadHeaderFile() throws CheckstyleException {
108        checkHeaderNotInitialized();
109        Reader headerReader = null;
110        try {
111            final URI uri = CommonUtils.getUriByFilename(headerFile);
112            headerReader = new InputStreamReader(new BufferedInputStream(
113                    uri.toURL().openStream()), charset);
114            loadHeader(headerReader);
115        }
116        catch (final IOException ex) {
117            throw new CheckstyleException(
118                    "unable to load header file " + headerFile, ex);
119        }
120        finally {
121            Closeables.closeQuietly(headerReader);
122        }
123    }
124
125    /**
126     * Called before initializing the header.
127     * @throws ConversionException if header has already been set
128     */
129    private void checkHeaderNotInitialized() {
130        if (!readerLines.isEmpty()) {
131            throw new ConversionException(
132                    "header has already been set - "
133                    + "set either header or headerFile, not both");
134        }
135    }
136
137    /**
138     * Set the header to check against. Individual lines in the header
139     * must be separated by '\n' characters.
140     * @param header header content to check against.
141     * @throws ConversionException if the header cannot be interpreted
142     */
143    public void setHeader(String header) {
144        if (StringUtils.isBlank(header)) {
145            return;
146        }
147
148        checkHeaderNotInitialized();
149
150        final String headerExpandedNewLines = ESCAPED_LINE_FEED_PATTERN
151                .matcher(header).replaceAll("\n");
152
153        final Reader headerReader = new StringReader(headerExpandedNewLines);
154        try {
155            loadHeader(headerReader);
156        }
157        catch (final IOException ex) {
158            throw new ConversionException("unable to load header", ex);
159        }
160        finally {
161            Closeables.closeQuietly(headerReader);
162        }
163    }
164
165    /**
166     * Load header to check against from a Reader into readerLines.
167     * @param headerReader delivers the header to check against
168     * @throws IOException if
169     */
170    private void loadHeader(final Reader headerReader) throws IOException {
171        final LineNumberReader lnr = new LineNumberReader(headerReader);
172        readerLines.clear();
173        while (true) {
174            final String line = lnr.readLine();
175            if (line == null) {
176                break;
177            }
178            readerLines.add(line);
179        }
180        postProcessHeaderLines();
181    }
182
183    @Override
184    protected final void finishLocalSetup() throws CheckstyleException {
185        if (headerFile != null) {
186            loadHeaderFile();
187        }
188        if (readerLines.isEmpty()) {
189            setHeader(null);
190        }
191    }
192}