AbstractParser

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 * distributed with this work for additional information
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 * 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
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package org.apache.maven.doxia.parser;

import javax.inject.Inject;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;

import org.apache.maven.doxia.macro.Macro;
import org.apache.maven.doxia.macro.MacroExecutionException;
import org.apache.maven.doxia.macro.MacroRequest;
import org.apache.maven.doxia.macro.manager.MacroManager;
import org.apache.maven.doxia.macro.manager.MacroNotFoundException;
import org.apache.maven.doxia.sink.Sink;
import org.apache.maven.doxia.sink.impl.CreateAnchorsForIndexEntriesFactory;
import org.apache.maven.doxia.sink.impl.SinkWrapperFactory;
import org.apache.maven.doxia.sink.impl.SinkWrapperFactoryComparator;

/**
 * An abstract base class that defines some convenience methods for parsers.
 * Provides a macro mechanism to give dynamic functionalities for the parsing.
 *
 * @author Jason van Zyl
 * @since 1.0
 */
public abstract class AbstractParser implements Parser {
    /** Indicates that a second parsing is required. */
    private boolean secondParsing = false;

    @Inject
    private MacroManager macroManager;

    @Inject
    private Collection<SinkWrapperFactory> automaticallyRegisteredSinkWrapperFactories;

    private final Collection<SinkWrapperFactory> manuallyRegisteredSinkWrapperFactories = new LinkedList<>();

    /**
     * Emit Doxia comment events when parsing comments?
     */
    private boolean emitComments = true;

    private boolean emitAnchors = false;

    private static final String DOXIA_VERSION;

    static {
        final Properties props = new Properties();
        final InputStream is = AbstractParser.class.getResourceAsStream(
                "/META-INF/maven/org.apache.maven.doxia/doxia-core/pom.properties");

        if (is == null) {
            props.setProperty("version", "unknown"); // should not happen
        } else {
            try {
                props.load(is);
            } catch (IOException ex) {
                props.setProperty("version", "unknown"); // should not happen
            } finally {
                try {
                    is.close();
                } catch (IOException ex) {
                    // oh well...
                }
            }
        }

        DOXIA_VERSION = props.getProperty("version");
    }

    /**
     * {@inheritDoc}
     *
     * @return a int
     */
    public int getType() {
        return UNKNOWN_TYPE;
    }

    /** {@inheritDoc} */
    public void setEmitComments(boolean emitComments) {
        this.emitComments = emitComments;
    }

    /**
     * <p>isEmitComments.</p>
     *
     * @return a boolean
     */
    public boolean isEmitComments() {
        return emitComments;
    }

    @Override
    public boolean isEmitAnchorsForIndexableEntries() {
        return emitAnchors;
    }

    @Override
    public void setEmitAnchorsForIndexableEntries(boolean emitAnchors) {
        this.emitAnchors = emitAnchors;
    }

    /**
     * Execute a macro on the given sink.
     *
     * @param macroId an id to lookup the macro
     * @param request the corresponding MacroRequest
     * @param sink the sink to receive the events
     * @throws org.apache.maven.doxia.macro.MacroExecutionException if an error occurred during execution
     * @throws org.apache.maven.doxia.macro.manager.MacroNotFoundException if the macro could not be found
     */
    // Made public right now because of the structure of the APT parser and
    // all its inner classes.
    public void executeMacro(String macroId, MacroRequest request, Sink sink)
            throws MacroExecutionException, MacroNotFoundException {
        Macro macro = getMacroManager().getMacro(macroId);

        macro.execute(sink, request);
    }

    /**
     * Returns the current base directory.
     *
     * @return the base directory
     * @deprecated this does not work in multi-module builds, see DOXIA-373
     */
    protected File getBasedir() {
        // TODO: This is baaad, it should come in with the request.
        // (this is only used for macro requests, see AptParser)

        String basedir = System.getProperty("basedir");

        if (basedir != null) {
            return new File(basedir);
        }

        return new File(new File("").getAbsolutePath());
    }

    /**
     * Convenience method to parse an arbitrary string and emit events into the given sink.
     *
     * @param string a string that provides the source input
     * @param sink a sink that consumes the Doxia events
     * @throws org.apache.maven.doxia.parser.ParseException if the string could not be parsed
     * @since 1.1
     */
    public void parse(String string, Sink sink) throws ParseException {
        this.parse(string, sink, null);
    }

    /**
     * Convenience method to parse an arbitrary string and emit events into the given sink.
     *
     * @param string a string that provides the source input
     * @param sink a sink that consumes the Doxia events
     * @param reference a string containing the reference to the source of the input string (e.g. filename)
     * @throws org.apache.maven.doxia.parser.ParseException if the string could not be parsed
     * @since 1.10
     */
    public void parse(String string, Sink sink, String reference) throws ParseException {
        parse(new StringReader(string), sink, reference);
    }

    /** {@inheritDoc} */
    @Override
    public void parse(Reader source, Sink sink) throws ParseException {
        parse(source, sink, null);
    }

    /**
     * Creates a sink pipeline built from all registered {@link SinkWrapperFactory} objects.
     * For secondary parsers (i.e. ones with {@link #isSecondParsing()} returning {@code true} just the given original sink is returned.
     * @param sink
     * @return the Sink pipeline to be used
     */
    protected Sink getWrappedSink(Sink sink) {
        // no wrapping for secondary parsing
        if (secondParsing) {
            return sink;
        }
        Sink currentSink = sink;
        for (SinkWrapperFactory factory : getSinkWrapperFactories()) {
            currentSink = factory.createWrapper(currentSink);
        }
        return currentSink;
    }

    /**
     * Set <code>secondParsing</code> to true, if this represents a secondary parsing of the same source.
     *
     * @param second true for second parsing
     */
    public void setSecondParsing(boolean second) {
        this.secondParsing = second;
    }

    /**
     * Indicates if we are currently parsing a second time.
     *
     * @return true if we are currently parsing a second time
     * @since 1.1
     */
    protected boolean isSecondParsing() {
        return secondParsing;
    }

    @Override
    public void addSinkWrapperFactory(SinkWrapperFactory factory) {
        manuallyRegisteredSinkWrapperFactories.add(factory);
    }

    /**
     * Returns all sink wrapper factories (both registered automatically and manually). The collection is ordered in a way that
     * the factories having the lowest priority come first (i.e. in reverse order).
     * @return all sink wrapper factories in the reverse order
     * @since 2.0.0
     */
    protected List<SinkWrapperFactory> getSinkWrapperFactories() {
        List<SinkWrapperFactory> effectiveSinkWrapperFactories = new ArrayList<>();
        if (automaticallyRegisteredSinkWrapperFactories != null) {
            effectiveSinkWrapperFactories.addAll(automaticallyRegisteredSinkWrapperFactories);
        }
        effectiveSinkWrapperFactories.addAll(manuallyRegisteredSinkWrapperFactories);
        if (emitAnchors) {
            effectiveSinkWrapperFactories.add(new CreateAnchorsForIndexEntriesFactory());
        }
        Collections.sort(effectiveSinkWrapperFactories, Collections.reverseOrder(new SinkWrapperFactoryComparator()));
        return effectiveSinkWrapperFactories;
    }

    /**
     * Gets the current {@link MacroManager}.
     *
     * @return the current {@link MacroManager}
     * @since 1.1
     */
    protected MacroManager getMacroManager() {
        return macroManager;
    }

    /**
     * Initialize the parser. This is called first by
     * {@link #parse(java.io.Reader, org.apache.maven.doxia.sink.Sink)} and can be used
     * to set the parser into a clear state so it can be re-used.
     *
     * @since 1.1.2
     */
    protected void init() {
        // nop
    }

    /**
     * The current Doxia version.
     *
     * @return the current Doxia version as a String
     * @since 1.2
     */
    protected static String doxiaVersion() {
        return DOXIA_VERSION;
    }
}