Gem.java

package com.aptana.rdt.core.gems;

import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

public class Gem implements Comparable<Gem>
{

	private String name;
	private String version;
	private String description;
	private String platform;

	/**
	 * Used by extension point for us to know whether the gem needs compilation (so we can make sure user's environment
	 * is set up for compilation).
	 */
	private boolean compiles = false;
	private boolean forceUpdates;

	public static final String RUBY_PLATFORM = "ruby";
	public static final String MSWIN32_PLATFORM = "mswin32";
	public static final String JRUBY_PLATFORM = "java";

	/**
	 * Used when we don't care what version to install!
	 */
	public static final String ANY_VERSION = "";

	public Gem(String name, String version, String description)
	{
		this(name, version, description, RUBY_PLATFORM);
	}

	public Gem(String name, String version, String description, String platform)
	{
		if (name == null)
			throw new IllegalArgumentException("A Gem's name must not be null");
		if (version == null)
			throw new IllegalArgumentException("A Gem's version must not be null");
		if (version.indexOf(",") != -1)
		{
			if (!(this instanceof LogicalGem))
				throw new IllegalArgumentException(
						"A Gem should have only one version. Use LogicalGem to group multiple versions of same gem.");
		}
		if (platform == null)
			throw new IllegalArgumentException("A Gem's platform must not be null");
		this.name = name;
		this.version = version;
		this.description = description;
		this.platform = platform;
	}

	public String getName()
	{
		return name;
	}

	public String getVersion()
	{
		return version;
	}

	public Version getVersionObject()
	{
		return new Version(version);
	}

	public String getDescription()
	{
		return description;
	}

	public String getPlatform()
	{
		return platform;
	}

	public boolean equals(Object arg0)
	{
		if (!(arg0 instanceof Gem))
			return false;
		Gem other = (Gem) arg0;
		return getName().equals(other.getName()) && getVersion().equals(other.getVersion())
				&& getPlatform().equals(other.getPlatform());
	}

	public int hashCode()
	{
		return (getName().hashCode() * 100) + getVersion().hashCode();
	}

	public int compareTo(Gem other)
	{
		return toString().compareTo(other.toString());
	}

	public String toString()
	{
		return getName().toLowerCase() + " " + getVersion() + " " + getPlatform();
	}

	public boolean hasMultipleVersions()
	{
		return version != null && version.indexOf(",") != -1;
	}

	public List<String> versions()
	{
		List<String> versions = new ArrayList<String>();
		if (version == null)
			return versions;
		StringTokenizer tokenizer = new StringTokenizer(version, ",");
		while (tokenizer.hasMoreTokens())
		{
			versions.add(tokenizer.nextToken().trim());
		}
		return versions;
	}

	/**
	 * Returns the absolute path to the local gem file (if this is a local gem that is being installed)
	 * 
	 * @return
	 */
	public String getAbsolutePath()
	{
		return null;
	}

	/**
	 * Return whether this is a gem that's being installed from a local File.
	 * 
	 * @return
	 */
	public boolean isLocal()
	{
		return false;
	}

	/**
	 * Only works on Local file gems. Deletes the original file.
	 */
	public void delete()
	{
		// do nothing
	}

	public boolean meetsRequirements(GemRequirement requirement)
	{
		if (!getName().equals(requirement.getName()))
			return false;

		return (requirement.meetsRequirements(getVersion()));
	}

	public void setCompiles(boolean compiles)
	{
		this.compiles = compiles;
	}

	public boolean compiles()
	{
		return compiles;
	}

	public boolean forceUpdates()
	{
		return forceUpdates;
	}

	public void setForceUpdate(boolean forceUpdate)
	{
		this.forceUpdates = forceUpdate;
	}
	
	public boolean isInstallable()
	{
		return true;
	}
}