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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.rest.vars;

import static org.apache.juneau.internal.StringUtils.*;

import java.io.*;

import org.apache.juneau.rest.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.svl.*;

/**
 * Serialized request attribute variable resolver.
 *
 * <p>
 * The format for this var is <js>"$SA{contentType,key[,defaultValue]}"</js>.
 *
 * <p>
 * This variable resolver requires that a {@link RestRequest} object be set as a context object on the resolver or a
 * session object on the resolver session.
 *
 * <p>
 * Since this is a {@link SimpleVar}, any variables contained in the result will be recursively resolved.
 * Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
 *
 * <ul class='seealso'>
 * 	<li class='link'>{@doc juneau-rest-server.SvlVariables}
 * </ul>
 */
public class SerializedRequestAttrVar extends StreamedVar {

	private static final String SESSION_req = "req";

	/** The name of this variable. */
	public static final String NAME = "SA";

	/**
	 * Constructor.
	 */
	public SerializedRequestAttrVar() {
		super(NAME);
	}

	@Override /* Var */
	public void resolveTo(VarResolverSession session, Writer w, String key) throws Exception {
		int i = key.indexOf(',');
		if (i == -1)
			throw new RuntimeException("Invalid format for $SA var.  Must be of the format $SA{contentType,key[,defaultValue]}");
		String[] s2 = split(key);
		RestRequest req = session.getSessionObject(RestRequest.class, SESSION_req, true);
		if (req != null) {
			Object o = req.getAttribute(key);
			if (o == null)
				o = key;
			Serializer s = req.getSerializers().getSerializer(s2[0]);
			if (s != null)
				s.serialize(w, o);
		}
	}

	@Override  /* Var */
	protected boolean allowNested() {
		return false;
	}

	@Override  /* Var */
	protected boolean allowRecurse() {
		return false;
	}

	@Override /* Var */
	public boolean canResolve(VarResolverSession session) {
		return session.hasSessionObject(SESSION_req);
	}
}
