FormatHelper.java

package com.venky.swf.integration;

import java.io.InputStream;
import java.lang.reflect.ParameterizedType;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.venky.swf.db.annotations.column.ui.mimes.MimeType;
import com.venky.swf.db.model.io.ModelIOFactory.UnsupportedMimeTypeException;


public abstract class FormatHelper<T> {
	protected FormatHelper(){
	
	}
	
	private static Map<MimeType,Class<?>> formatClassMap = new HashMap<MimeType, Class<?>>();
	private static Map<MimeType,FormatHelperBuilder<?>> formatBuilderMap = new HashMap<MimeType,FormatHelperBuilder<?>>();
	
	public static <T> void registerFormat(MimeType mimeType, Class<T> formatClass, FormatHelperBuilder<T> formatBuilder){
		formatClassMap.put(mimeType, formatClass);
		formatBuilderMap.put(mimeType, formatBuilder);
	}
	
	@SuppressWarnings("unchecked")
	public static <T> Class<T> getFormatClass(MimeType mimeType){
		Class<T> formatClass = (Class<T>) formatClassMap.get(mimeType);
		if (formatClass == null){
			throw new UnsupportedMimeTypeException(mimeType.toString());
		}
		return formatClass;
	}
	
	@SuppressWarnings("unchecked")
	public static <T> MimeType getMimeType(Class<T> clazz){
		for (MimeType mime :formatClassMap.keySet()){
			Class<T> formatClass = (Class<T>) formatClassMap.get(mime);
			if (formatClass.isAssignableFrom(clazz)){
				return mime;
			}
		}
		throw new UnsupportedMimeTypeException(clazz.getName());
	}
	
	@SuppressWarnings("unchecked")
	public Class<T> getFormatClass(){
		ParameterizedType pt = (ParameterizedType)this.getClass().getGenericSuperclass();
		return (Class<T>) pt.getActualTypeArguments()[0];
	}
	
	public MimeType getMimeType(){
		return getMimeType(getFormatClass());
	}
	
	@SuppressWarnings("unchecked")
	public static final <T> FormatHelper<T> instance(MimeType mimeType,String rootName,boolean isPlural){
		FormatHelper<T> helper = null;
		FormatHelperBuilder<T> formatHelperBuilder = (FormatHelperBuilder<T>) formatBuilderMap.get(mimeType);
		if (formatHelperBuilder != null){
			helper = formatHelperBuilder.constructFormatHelper(rootName, isPlural);
		}
		if (helper == null){
			throw new UnsupportedMimeTypeException(mimeType.toString());
		}
		return helper;
	}

	public static final <T>  FormatHelper<T> instance(T element){
		return instance(getMimeType(element.getClass()),element);
	}
	@SuppressWarnings("unchecked")
	public static final <T> FormatHelper<T> instance(MimeType mimeType, InputStream in){
		FormatHelper<T> helper = null;
		FormatHelperBuilder<T> formatHelperBuilder = (FormatHelperBuilder<T>) formatBuilderMap.get(mimeType);
		if (formatHelperBuilder != null){
			helper = formatHelperBuilder.constructFormatHelper(in);
		}
		if (helper == null){
			throw new UnsupportedMimeTypeException(mimeType.toString());
		}
		return helper;
	}
	@SuppressWarnings("unchecked")
	public static final <T> FormatHelper<T> instance(MimeType mimeType,T element){
		FormatHelper<T> helper = null;
		FormatHelperBuilder<T> formatHelperBuilder = (FormatHelperBuilder<T>) formatBuilderMap.get(mimeType);
		if (formatHelperBuilder != null){
			helper = formatHelperBuilder.constructFormatHelper(element);
		}
		if (helper == null){
			throw new UnsupportedMimeTypeException(mimeType.toString());
		}
		return (FormatHelper<T>) helper;
	}
	
	public abstract T getRoot();
	public abstract T createChildElement(String name);
	public abstract List<T> getChildElements(String name) ;
	
	public abstract T createElementAttribute(String name);
	public abstract T getElementAttribute(String name);
	
	public abstract void setAttribute(String name, String value);
	
	public abstract Set<String> getAttributes();
	public abstract String getAttribute(String name);

	
}