com.strategicgains.hyperexpress.domain.LinkDefinition Maven / Gradle / Ivy

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/*
    Copyright 2013, Strategic Gains, Inc.

	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.strategicgains.hyperexpress.domain;

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import com.strategicgains.hyperexpress.util.Strings;

/**
 * A LinkDefinition is a generic definition of a hypermedia link. It contains
 * attributes than can describe various output link formats such as HAL, Atom,
 * and JSON-LD.  It can contain, therefore, a superset of attributes for any
 * given destination link format.
 * 
 * At a minimum, a LinkDefinition must contain a 'rel' and an 'href' property,
 * which correspond to the relation type and associated URL, respectively.
 * 
 * LinkDefinition is Cloneable.
 * 
 * @author toddf
 * @since Oct 17, 2013
 */
public class LinkDefinition
implements Link
{
	private static final String REL_TYPE = "rel";
	private static final String HREF = "href";

	private Map attributes = new HashMap();

	public LinkDefinition(String rel, String href)
	{
		super();
		setRel(rel);
		setHref(href);
	}

	public LinkDefinition(LinkDefinition that)
	{
		super();

		if (that != null) this.attributes.putAll(that.attributes);
	}

	@Override
	public LinkDefinition clone()
	{
		return new LinkDefinition(this);
	}

	@Override
	public String getHref()
	{
		return get(HREF);
	}

	@Override
	public LinkDefinition setHref(String href)
	{
		set(HREF, href);
		return this;
	}

	@Override
	public String getRel()
	{
		return get(REL_TYPE);
	}

	@Override
	public LinkDefinition setRel(String rel)
	{
		set(REL_TYPE, rel);
		return this;
	}

	@Override
	public LinkDefinition set(String name, String value)
	{
		if (value == null)
		{
			attributes.remove(name);
		}
		else
		{
			attributes.put(name, value);
		}

		return this;
	}

	@Override
	public String get(String name)
	{
		return attributes.get(name);
	}

	@Override
	public boolean has(String name)
	{
		return (get(name) != null);
	}

	@Override
	public boolean hasToken()
	{
		return Strings.hasToken(getHref());
	}

	@Override
	public String toString()
	{
		StringBuilder s = new StringBuilder();
		s.append(this.getClass().getSimpleName());
		s.append("{");
		boolean isFirst = true;

		for (Entry entry : attributes.entrySet())
		{
			if (!isFirst)
			{
				s.append(", ");
			}
			else
			{
				isFirst = false;
			}

			s.append(entry.getKey());
			s.append("=");
			s.append(entry.getValue());
		}

		s.append("}");
		return s.toString();
	}

	@Override
	public int hashCode()
	{
		return 31 + ((attributes == null) ? 0 : attributes.hashCode());
	}

	@Override
	public boolean equals(Object that)
	{
		if (this == that) return true;
		if (that == null) return false;
		if (getClass() != that.getClass()) return false;

		return equals((LinkDefinition) that);
	}

	public boolean equals(LinkDefinition that)
	{
		if (attributes == null)
		{
			if (that.attributes != null)
			{
				return false;
			}
		}
		else if (!attributes.equals(that.attributes))
		{
			return false;
		}

		return true;
	}
}