org.apache.juneau.svl.vars.PatternReplaceVar Maven / Gradle / Ivy

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package org.apache.juneau.svl.vars;

import static org.apache.juneau.common.internal.ArgUtils.*;

import org.apache.juneau.svl.*;

/**
 * A transformational variable resolver that replaces matched patterns with given characters.
 *
 * 
 * The format for this var is:
 * 

 * 	"$PR{stringArg,pattern,replace}"
 * 
 *
 * 
 * The pattern can be any string optionally containing '*' or '?' representing any or one character
 * respectively.
 *
 * The replace can contain matched regex sub classes like \$1, \$2 ..
 *
 * 
Example:
 * 
 * 	// Create a variable resolver that resolves system properties and $SW vars.
 * 	VarResolver varResolver = VarResolver.create().vars(PatternReplaceVar.class, SystemPropertiesVar.class).build();
 *
 * 	// Use it!
 * 	System.out.println(varResolver.resolve("Java version=$PR{$S{java.version}, (_([0-9]+)), \\ build=\\$2}"));
 * 
 *
 * 
 * Since this is a {@link MultipartVar}, 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.
 *
 * 
See Also:

 * 	Simple Variable Language
 * 
 */
public class PatternReplaceVar extends MultipartVar {

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

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

	@Override /* MultipartVar */
	public String resolve(VarResolverSession session, String[] args) {
		assertArg(args.length >= 3, "Invalid number of arguments passed to $PR var.  Must have 3 or more arguments.");

		String stringArg = args[0];
		String pattern = args[1];
		String replace = args[2];

		pattern = pattern.replace("*", ".*").replace("?", ".");
		return stringArg.replaceAll(pattern, replace);
	}
}