QSpec.java

/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *******************************************************************************/
package org.andork.q;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.andork.collect.CollectionUtils;
import org.andork.reflect.ReflectionUtils;

public abstract class QSpec<S extends QSpec<S>> {
	public static class Attribute<T> {
		public static <T> Attribute<T> newInstance(Class<? super T> valueClass, String name) {
			return new Attribute<T>(valueClass, name);
		}

		final Class<? super T> valueClass;
		int index = -1;

		final String name;

		public Attribute(Class<? super T> valueClass, String name) {
			super();
			this.valueClass = valueClass;
			this.name = name;
		}

		public int getIndex() {
			return index;
		}

		public String getName() {
			return name;
		}

		public Class<? super T> getValueClass() {
			return valueClass;
		}

		@Override
		public String toString() {
			return getName();
		}
	}

	public static <T> Attribute<T> newAttribute(Class<? super T> valueClass, String name) {
		return new Attribute<T>(valueClass, name);
	}

	public static <S extends QSpec<S>> Attribute<QObject<S>> newAttribute(S spec, String name) {
		return new Attribute<QObject<S>>(QObject.class, name);
	}

	final Attribute<?>[] attributes;

	final List<Attribute<?>> attributeList;

	final Map<String, Attribute<?>> attributesByName = new LinkedHashMap<String, Attribute<?>>();

	protected QSpec() {
		for (Field field : ReflectionUtils.getStaticFieldList(getClass(), true)) {
			if (field.getType() == Attribute.class) {
				try {
					field.setAccessible(true);
					Attribute<?> attr = (Attribute<?>) field.get(null);
					attributesByName.put(attr.getName(), attr);
				} catch (Exception ex) {
					// Shouldn't happen...
				}
			}
		}
		this.attributes = attributesByName.values().toArray(new Attribute[attributesByName.size()]);

		for (int i = 0; i < attributes.length; i++) {
			if (attributes[i].index < 0) {
				attributes[i].index = i;
			} else if (attributes[i].index != i) {
				throw new IllegalStateException("attribute order conflicts with another spec");
			}
		}
		this.attributeList = Collections.unmodifiableList(Arrays.asList(attributes));
	}

	protected QSpec(Attribute<?>... attributes) {
		this(Arrays.asList(attributes));
	}

	protected QSpec(Iterable<Attribute<?>> attrIterable) {
		for (Attribute<?> attr : attrIterable) {
			attributesByName.put(attr.getName(), attr);
		}
		ArrayList<Attribute<?>> attrList = CollectionUtils.toArrayList(attrIterable);
		attrList.trimToSize();
		attributeList = Collections.unmodifiableList(attrList);
		attributes = attributeList.toArray(new Attribute[attributeList.size()]);

		for (int i = 0; i < attributeList.size(); i++) {
			if (attributes[i].index < 0) {
				attributes[i].index = i;
			} else if (attributes[i].index != i) {
				throw new IllegalArgumentException("attributes[" + i + "].index == " + attributes[i].index);
			}
		}
	}

	public Attribute<?> attributeAt(int index) {
		return attributes[index];
	}

	public Attribute<?> getAttribute(String name) {
		return attributesByName.get(name);
	}

	public int getAttributeCount() {
		return attributes.length;
	}

	public List<Attribute<?>> getAttributes() {
		return attributeList;
	}

	public QObject<S> newObject() {
		return QObject.newInstance((S) this);
	}
}