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Java CSS 3 parser and builder
/**
* Copyright (C) 2014-2016 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* 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 com.helger.css.reader;
import java.io.File;
import java.io.InputStream;
import java.io.Reader;
import java.nio.charset.Charset;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.WillClose;
import javax.annotation.concurrent.GuardedBy;
import javax.annotation.concurrent.Immutable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.helger.commons.ValueEnforcer;
import com.helger.commons.annotation.PresentForCodeCoverage;
import com.helger.commons.concurrent.SimpleReadWriteLock;
import com.helger.commons.io.IHasInputStream;
import com.helger.commons.io.resource.FileSystemResource;
import com.helger.commons.io.resource.IReadableResource;
import com.helger.commons.io.stream.NonBlockingStringReader;
import com.helger.commons.io.stream.StreamHelper;
import com.helger.css.ECSSVersion;
import com.helger.css.decl.CSSDeclarationList;
import com.helger.css.handler.CSSHandler;
import com.helger.css.handler.DoNothingCSSParseExceptionCallback;
import com.helger.css.handler.ICSSParseExceptionCallback;
import com.helger.css.handler.LoggingCSSParseExceptionCallback;
import com.helger.css.parser.CSSCharStream;
import com.helger.css.parser.CSSNode;
import com.helger.css.parser.CharStream;
import com.helger.css.parser.ParseException;
import com.helger.css.parser.ParserCSS30;
import com.helger.css.parser.ParserCSS30TokenManager;
import com.helger.css.reader.errorhandler.ICSSParseErrorHandler;
import com.helger.css.reader.errorhandler.ThrowingCSSParseErrorHandler;
/**
* This is the central user class for reading and parsing partial CSS from
* different sources. This class reads CSS style declarations as used in HTML
* <style> attributes only.
*
* @author Philip Helger
*/
@Immutable
public final class CSSReaderDeclarationList
{
private static final Logger s_aLogger = LoggerFactory.getLogger (CSSReaderDeclarationList.class);
private static final SimpleReadWriteLock s_aRWLock = new SimpleReadWriteLock ();
// Use the ThrowingCSSParseErrorHandler for maximum backward compatibility
@GuardedBy ("s_aRWLock")
private static ICSSParseErrorHandler s_aDefaultParseErrorHandler = new ThrowingCSSParseErrorHandler ();
// Use the LoggingCSSParseExceptionHandler for maximum backward compatibility
@GuardedBy ("s_aRWLock")
private static ICSSParseExceptionCallback s_aDefaultParseExceptionHandler = new LoggingCSSParseExceptionCallback ();
@PresentForCodeCoverage
private static final CSSReaderDeclarationList s_aInstance = new CSSReaderDeclarationList ();
private CSSReaderDeclarationList ()
{}
/**
* @return The default CSS parse error handler. May be null. For
* backwards compatibility reasons this is be default an instance of
* {@link ThrowingCSSParseErrorHandler}.
* @since 3.7.4
*/
@Nullable
public static ICSSParseErrorHandler getDefaultParseErrorHandler ()
{
return s_aRWLock.readLocked ( () -> s_aDefaultParseErrorHandler);
}
/**
* Set the default CSS parse error handler (for recoverable errors).
*
* @param aDefaultParseErrorHandler
* The new default error handler to be used. May be null
* to indicate that no special error handler should be used.
* @since 3.7.4
*/
public static void setDefaultParseErrorHandler (@Nullable final ICSSParseErrorHandler aDefaultParseErrorHandler)
{
s_aRWLock.writeLocked ( () -> {
s_aDefaultParseErrorHandler = aDefaultParseErrorHandler;
});
}
/**
* @return The default CSS parse exception handler. May not be
* null. For backwards compatibility reasons this is be
* default an instance of {@link LoggingCSSParseExceptionCallback}.
* @since 3.7.4
*/
@Nonnull
public static ICSSParseExceptionCallback getDefaultParseExceptionHandler ()
{
return s_aRWLock.readLocked ( () -> s_aDefaultParseExceptionHandler);
}
/**
* Set the default CSS parse exception handler (for unrecoverable errors).
*
* @param aDefaultParseExceptionHandler
* The new default exception handler to be used. May not be
* null.
* @since 3.7.4
*/
public static void setDefaultParseExceptionHandler (@Nonnull final ICSSParseExceptionCallback aDefaultParseExceptionHandler)
{
ValueEnforcer.notNull (aDefaultParseExceptionHandler, "DefaultParseExceptionHandler");
s_aRWLock.writeLocked ( () -> {
s_aDefaultParseExceptionHandler = aDefaultParseExceptionHandler;
});
}
/**
* Main reading of the CSS
*
* @param aCharStream
* The stream to read from. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* A custom handler for recoverable errors. May be null.
* @param aCustomExceptionHandler
* A custom handler for unrecoverable errors. May not be
* null.
* @return null if parsing failed with an unrecoverable error
* (and no throwing exception handler is used), or null
* if a recoverable error occurred and no
* {@link com.helger.css.reader.errorhandler.ThrowingCSSParseErrorHandler}
* was used or non-null if parsing succeeded.
*/
@Nullable
private static CSSNode _readStyleDeclaration (@Nonnull final CharStream aCharStream,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nonnull final ICSSParseExceptionCallback aCustomExceptionHandler)
{
switch (eVersion)
{
case CSS21:
case CSS30:
{
final ParserCSS30TokenManager aTokenHdl = new ParserCSS30TokenManager (aCharStream);
final ParserCSS30 aParser = new ParserCSS30 (aTokenHdl);
aParser.setCustomErrorHandler (aCustomErrorHandler);
try
{
// Main parsing
return aParser.styleDeclarationList ();
}
catch (final ParseException ex)
{
// Unrecoverable error
aCustomExceptionHandler.onException (ex);
return null;
}
}
default:
throw new IllegalArgumentException ("Unsupported CSS version " + eVersion);
}
}
/**
* Check if the passed CSS file can be parsed without error
*
* @param aFile
* The file to be parsed. May not be null.
* @param aCharset
* The charset to be used for reading the CSS file. May not be
* null.
* @param eVersion
* The CSS version to be used for scanning. May not be
* null.
* @return true if the file can be parsed without error,
* false if not
*/
public static boolean isValidCSS (@Nonnull final File aFile,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
return isValidCSS (new FileSystemResource (aFile), aCharset, eVersion);
}
/**
* Check if the passed CSS resource can be parsed without error
*
* @param aRes
* The resource to be parsed. May not be null.
* @param aCharset
* The charset to be used for reading the CSS file. May not be
* null.
* @param eVersion
* The CSS version to be used for scanning. May not be
* null.
* @return true if the file can be parsed without error,
* false if not
*/
public static boolean isValidCSS (@Nonnull final IReadableResource aRes,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
ValueEnforcer.notNull (aRes, "Resource");
ValueEnforcer.notNull (aCharset, "Charset");
ValueEnforcer.notNull (eVersion, "Version");
final Reader aReader = aRes.getReader (aCharset);
if (aReader == null)
{
s_aLogger.warn ("Failed to open CSS reader " + aRes);
return false;
}
return isValidCSS (aReader, eVersion);
}
/**
* Check if the passed input stream can be resembled to valid CSS content.
* This is accomplished by fully parsing the CSS file each time the method is
* called. This is similar to calling
* {@link #readFromStream(IHasInputStream,Charset, ECSSVersion)} and checking
* for a non-null result.
*
* @param aIS
* The input stream to use. Is automatically closed. May not be
* null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return true if the CSS is valid according to the version,
* false if not
*/
public static boolean isValidCSS (@Nonnull @WillClose final InputStream aIS,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
ValueEnforcer.notNull (aIS, "InputStream");
ValueEnforcer.notNull (aCharset, "Charset");
return isValidCSS (StreamHelper.createReader (aIS, aCharset), eVersion);
}
/**
* Check if the passed String can be resembled to valid CSS content. This is
* accomplished by fully parsing the CSS file each time the method is called.
* This is similar to calling {@link #readFromString(String, ECSSVersion)} and
* checking for a non-null result.
*
* @param sCSS
* The CSS string to scan. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return true if the CSS is valid according to the version,
* false if not
*/
public static boolean isValidCSS (@Nonnull final String sCSS, @Nonnull final ECSSVersion eVersion)
{
ValueEnforcer.notNull (sCSS, "CSS");
return isValidCSS (new NonBlockingStringReader (sCSS), eVersion);
}
/**
* Check if the passed reader can be resembled to valid CSS content. This is
* accomplished by fully parsing the CSS each time the method is called. This
* is similar to calling
* {@link #readFromStream(IHasInputStream, Charset, ECSSVersion)} and checking
* for a non-null result.
*
* @param aReader
* The reader to use. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return true if the CSS is valid according to the version,
* false if not
*/
public static boolean isValidCSS (@Nonnull @WillClose final Reader aReader, @Nonnull final ECSSVersion eVersion)
{
ValueEnforcer.notNull (aReader, "Reader");
ValueEnforcer.notNull (eVersion, "Version");
try
{
final CSSCharStream aCharStream = new CSSCharStream (aReader);
final CSSNode aNode = _readStyleDeclaration (aCharStream,
eVersion,
getDefaultParseErrorHandler (),
new DoNothingCSSParseExceptionCallback ());
return aNode != null;
}
finally
{
StreamHelper.close (aReader);
}
}
@Nullable
public static CSSDeclarationList readFromString (@Nonnull final String sCSS, @Nonnull final ECSSVersion eVersion)
{
return readFromReader (new NonBlockingStringReader (sCSS), new CSSReaderSettings ().setCSSVersion (eVersion));
}
@Nullable
public static CSSDeclarationList readFromString (@Nonnull final String sCSS,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler)
{
return readFromReader (new NonBlockingStringReader (sCSS),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler));
}
@Nullable
public static CSSDeclarationList readFromString (@Nonnull final String sCSS,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (new NonBlockingStringReader (sCSS),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
@Nullable
public static CSSDeclarationList readFromString (@Nonnull final String sCSS,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (new NonBlockingStringReader (sCSS),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
@Nullable
public static CSSDeclarationList readFromFile (@Nonnull final File aFile,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
return readFromReader (new FileSystemResource (aFile).getReader (aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion));
}
@Nullable
public static CSSDeclarationList readFromFile (@Nonnull final File aFile,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler)
{
return readFromReader (new FileSystemResource (aFile).getReader (aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler));
}
@Nullable
public static CSSDeclarationList readFromFile (@Nonnull final File aFile,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (new FileSystemResource (aFile).getReader (aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
@Nullable
public static CSSDeclarationList readFromFile (@Nonnull final File aFile,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (new FileSystemResource (aFile).getReader (aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link IHasInputStream}.
*
* @param aISP
* The input stream provider to use. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull final IHasInputStream aISP,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
return readFromStream (aISP, aCharset, eVersion, null, null);
}
/**
* Read the CSS from the passed {@link IHasInputStream}.
*
* @param aISP
* The input stream provider to use. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull final IHasInputStream aISP,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler)
{
return readFromStream (aISP, aCharset, eVersion, aCustomErrorHandler, null);
}
/**
* Read the CSS from the passed {@link IHasInputStream}.
*
* @param aISP
* The input stream provider to use. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull final IHasInputStream aISP,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromStream (aISP, aCharset, eVersion, null, aCustomExceptionHandler);
}
/**
* Read the CSS from the passed {@link IHasInputStream}.
*
* @param aISP
* The input stream provider to use. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull final IHasInputStream aISP,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
ValueEnforcer.notNull (aISP, "InputStreamProvider");
final InputStream aIS = aISP.getInputStream ();
if (aIS == null)
return null;
return readFromReader (StreamHelper.createReader (aIS, aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link InputStream}.
*
* @param aIS
* The input stream to use. Will be closed automatically after reading
* - independent of success or error. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return null if reading failed, the CSS declarations
* otherwise.
* @since 3.7.4
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull @WillClose final InputStream aIS,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion)
{
return readFromReader (StreamHelper.createReader (aIS, aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion));
}
/**
* Read the CSS from the passed {@link InputStream}.
*
* @param aIS
* The input stream to use. Will be closed automatically after reading
* - independent of success or error. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
* @since 3.7.4
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull @WillClose final InputStream aIS,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler)
{
return readFromReader (StreamHelper.createReader (aIS, aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler));
}
/**
* Read the CSS from the passed {@link InputStream}.
*
* @param aIS
* The input stream to use. Will be closed automatically after reading
* - independent of success or error. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
* @since 3.7.4
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull @WillClose final InputStream aIS,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (StreamHelper.createReader (aIS, aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link InputStream}.
*
* @param aIS
* The input stream to use. Will be closed automatically after reading
* - independent of success or error. May not be null.
* @param aCharset
* The charset to be used. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
* @since 3.7.4
*/
@Nullable
public static CSSDeclarationList readFromStream (@Nonnull @WillClose final InputStream aIS,
@Nonnull final Charset aCharset,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
ValueEnforcer.notNull (aIS, "InputStream");
return readFromReader (StreamHelper.createReader (aIS, aCharset),
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link Reader}.
*
* @param aReader
* The reader to use. Will be closed automatically after reading -
* independent of success or error. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromReader (@Nonnull @WillClose final Reader aReader,
@Nonnull final ECSSVersion eVersion)
{
return readFromReader (aReader, new CSSReaderSettings ().setCSSVersion (eVersion));
}
/**
* Read the CSS from the passed {@link Reader}.
*
* @param aReader
* The reader to use. Will be closed automatically after reading -
* independent of success or error. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromReader (@Nonnull @WillClose final Reader aReader,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler)
{
return readFromReader (aReader,
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler));
}
/**
* Read the CSS from the passed {@link Reader}.
*
* @param aReader
* The reader to use. Will be closed automatically after reading -
* independent of success or error. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromReader (@Nonnull @WillClose final Reader aReader,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (aReader,
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link Reader}.
*
* @param aReader
* The reader to use. Will be closed automatically after reading -
* independent of success or error. May not be null.
* @param eVersion
* The CSS version to use. May not be null.
* @param aCustomErrorHandler
* An optional custom error handler that can be used to collect the
* recoverable parsing errors. May be null.
* @param aCustomExceptionHandler
* An optional custom exception handler that can be used to collect the
* unrecoverable parsing errors. May be null.
* @return null if reading failed, the CSS declarations
* otherwise.
*/
@Nullable
public static CSSDeclarationList readFromReader (@Nonnull @WillClose final Reader aReader,
@Nonnull final ECSSVersion eVersion,
@Nullable final ICSSParseErrorHandler aCustomErrorHandler,
@Nullable final ICSSParseExceptionCallback aCustomExceptionHandler)
{
return readFromReader (aReader,
new CSSReaderSettings ().setCSSVersion (eVersion)
.setCustomErrorHandler (aCustomErrorHandler)
.setCustomExceptionHandler (aCustomExceptionHandler));
}
/**
* Read the CSS from the passed {@link Reader}.
*
* @param aReader
* The reader to use. Will be closed automatically after reading -
* independent of success or error. May not be null.
* @param aSettings
* The settings to be used for reading the CSS. May not be
* null.
* @return null if reading failed, the CSS declarations
* otherwise.
* @since 3.8.2
*/
@Nullable
public static CSSDeclarationList readFromReader (@Nonnull @WillClose final Reader aReader,
@Nonnull final CSSReaderSettings aSettings)
{
ValueEnforcer.notNull (aReader, "Reader");
ValueEnforcer.notNull (aSettings, "Settings");
final ECSSVersion eVersion = aSettings.getCSSVersion ();
try
{
final CSSCharStream aCharStream = new CSSCharStream (aReader);
// Use the default CSS parse error handler if none is provided
ICSSParseErrorHandler aRealErrorHandler = aSettings.getCustomErrorHandler ();
if (aRealErrorHandler == null)
aRealErrorHandler = getDefaultParseErrorHandler ();
// Use the default CSS exception handler if none is provided
ICSSParseExceptionCallback aRealExceptionHandler = aSettings.getCustomExceptionHandler ();
if (aRealExceptionHandler == null)
aRealExceptionHandler = getDefaultParseExceptionHandler ();
final CSSNode aNode = _readStyleDeclaration (aCharStream, eVersion, aRealErrorHandler, aRealExceptionHandler);
// Failed to interpret content as CSS?
if (aNode == null)
return null;
// Convert the AST to a domain object
return CSSHandler.readDeclarationListFromNode (eVersion, aNode);
}
finally
{
StreamHelper.close (aReader);
}
}
}
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