itextpdf-master/xmlworker/src/main/java/com/itextpdf/tool/xml/html/DefaultTagProcessorFactory.java
/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2022 iText Group NV
 * Authors: Balder Van Camp, Emiel Ackermann, et al.
 *
 * This program is free software; you can redistribute it and/or modify
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 *
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package com.itextpdf.tool.xml.html;

import com.itextpdf.tool.xml.exceptions.LocaleMessages;
import com.itextpdf.tool.xml.exceptions.NoTagProcessorException;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * A Default implementation of the TagProcessorFactory that uses a map to store
 * the TagProcessors. Within the same {@link ClassLoader}s this Processor can
 * also load the processors when they are only stored with there fully qualified
 * class names.<br />
 * <strong>Note:</strong> this implementation does not use namespaces (yet)!
 *
 *
 * @author redlab_b
 *
 */
public class DefaultTagProcessorFactory implements TagProcessorFactory {

	/**
	 * Internal Object to keep TagProcessors.
	 * @author redlab_b
	 *
	 */
	protected final class FactoryObject {
		private final String className;
		private TagProcessor proc;

		/**
		 * @param className the fully qualified class name
		 *
		 */
		public FactoryObject(final String className) {
			this.className = className;
		}

		/**
		 * @param className the fully qualified class name
		 * @param processor the processor object
		 */
		public FactoryObject(final String className, final TagProcessor processor) {
			this(className);
			this.proc = processor;

		}

		/**
		 *
		 * @return the className
		 */
		public String getClassName() {
			return this.className;
		}

		/**
		 * @return return the processor
		 */
		public TagProcessor getProcessor() {
			if (null == this.proc) {
				this.proc = load(this.className);
			}
			return proc;
		}

	}

	private final Map<String, FactoryObject> map;

	/**
	 *
	 */
	public DefaultTagProcessorFactory() {
		this.map = new ConcurrentHashMap<String, FactoryObject>();
	}

	/**
	 * Tries to load given processor with Class.forName
	 * @param className fully qualified className
	 * @return the loaded tag processor
	 * @throws NoTagProcessorException if TagProcessor could not be loaded.
	 */
	protected TagProcessor load(final String className) throws NoTagProcessorException {
		try {
			Class<?> c = Class.forName(className);
			return (TagProcessor) c.newInstance();
		} catch (LinkageError e) {
			throw new NoTagProcessorException(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className));
		} catch (ClassNotFoundException e) {
			throw new NoTagProcessorException(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		} catch (InstantiationException e) {
			throw new NoTagProcessorException(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		} catch (IllegalAccessException e) {
			throw new NoTagProcessorException(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		}

	}

	/**
	 * Tries to load given processor with Class.forName
	 * 
	 * @param className fully qualified className
	 * @param loader the classloader to use
	 * @return the loaded tag processor
	 * @throws NoTagProcessorException if TagProcessor could not be loaded.
	 */
	protected TagProcessor load(final String className, final ClassLoader loader) throws NoTagProcessorException {
		try {
			Class<?> c = loader.loadClass(className);
			return (TagProcessor) c.newInstance();
		} catch (LinkageError e) {
			throw new NoTagProcessorException(String.format(
					LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className));
		} catch (ClassNotFoundException e) {
			throw new NoTagProcessorException(String.format(
					LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		} catch (InstantiationException e) {
			throw new NoTagProcessorException(String.format(
					LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		} catch (IllegalAccessException e) {
			throw new NoTagProcessorException(String.format(
					LocaleMessages.getInstance().getMessage(LocaleMessages.NO_TAGPROCESSOR), className), e);
		}

	}

	/**
	 * @throws NoTagProcessorException when the processor was not found for the given tag.
	 */
	public TagProcessor getProcessor(final String tag, final String nameSpace) {
		FactoryObject fo = map.get(tag.toLowerCase());
		if (fo != null) {
			return fo.getProcessor();
		}
		throw new NoTagProcessorException(tag);
	}

	/**
	 * Add an unloaded TagProcessor.
	 *
	 * @param tag the tag the processor with the given className maps to
	 * @param className the fully qualified class name (class has to be found on classpath, will be loaded with Class.forName()
	 */
	public void addProcessor(final String tag, final String className) {
		map.put(tag, new FactoryObject(className));
	}

	/**
	 * Add a loaded TagProcessor.
	 *
	 * @param tag the tag the processor with the given className maps to
	 * @param processor the TagProcessor
	 */
	public void addProcessor(final String tag, final TagProcessor processor) {
		map.put(tag, new FactoryObject(processor.getClass().getName(), processor));

	}
	/**
	 *
	 */
	public void addProcessor( final TagProcessor processor, final String ... tags) {
		for (String tag : tags) {
			addProcessor(tag, processor);
		}
	}
	/**
	 * Add one tag processor that handles multiple tags.
	 * @param className the fully qualified class name (class has to be found on classpath)
	 * @param tags list of tags this processor maps to.
	 */
	public void addProcessor( final String className, final String ... tags) {
		for (String tag : tags) {
			addProcessor(tag, className);
		}
	}

	/* (non-Javadoc)
	 * @see com.itextpdf.tool.xml.html.TagProcessorFactory#removeProcessor(java.lang.String)
	 */
	public void removeProcessor(final String tag) {
		map.remove(tag);
	}

}
