juneau-core/juneau-marshall/src/main/java/org/apache/juneau/svl/SimpleVar.java

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package org.apache.juneau.svl;

import java.io.*;

/**
 * Abstract superclass of all Simple Var Language variables that resolve to simple returned string values.
 *
 * <p>
 * Note the difference between this class and {@link StreamedVar} that streams values to writers.
 * <br>Unlike the {@link StreamedVar} class, the returned value from this class can contain nested variables that will be
 * recursively resolved by {@link VarResolver}.
 *
 * <p>
 * Subclasses must implement the following method:
 * <ul class='javatree'>
 * 	<li class='jm'>{@link #resolve(VarResolverSession, String)}
 * </ul>
 *
 * <ul class='seealso'>
 * 	<li class='link'>{@doc juneau-marshall.SimpleVariableLanguage.SvlVariables}
 * </ul>
 */
public abstract class SimpleVar extends Var {

	/**
	 * Constructor.
	 *
	 * @param name The variable name (e.g. <js>"C"</js> for variables of the form <js>"$C{...}"</js>)
	 */
	protected SimpleVar(String name) {
		super(name, false);
	}

	@Override /* Var */
	public void resolveTo(VarResolverSession session, Writer w, String arg) throws Exception {
		throw new UnsupportedOperationException("Cannot call streamTo() on SimpleVar class");
	}
}