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/**
 * Copyright 2007 Charlie Hubbard
 *
 * 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 flexjson;

import java.util.Arrays;

/**
 * This is an internal class for Flexjson.  It's used to match on fields it encounters
 * while walking the object graph.  Every expression is expressed in dot notation like foo.bar.baz.  Each term
 * between the dots is a field name in that parent object.  All expressions are relative to some parent object
 * within the context in which they are used.  Typically it is the object you're serializing.  Expressions may
 * also contain wildcards like *.class.
 */
public class PathExpression
{
	String[] expression;
	boolean wildcard= false;
	boolean included= true;

	public PathExpression(String expr, boolean anInclude)
	{
		expression= expr.split("\\.");
		wildcard= expr.indexOf('*') >= 0;
		included= anInclude;
	}

	public String toString()
	{
		StringBuilder builder= new StringBuilder();
		builder.append("[");
		for (int i= 0; i < expression.length; i++)
		{
			builder.append(expression[i]);
			if (i < expression.length - 1)
			{
				builder.append(",");
			}
		}
		builder.append("]");
		return builder.toString();
	}

	public boolean matches(Path path)
	{
		int exprCurrentIndex= 0;
		int pathCurrentIndex= 0;
		while (pathCurrentIndex < path.length())
		{
			String current= path.getPath().get(pathCurrentIndex);
			if (exprCurrentIndex < expression.length && expression[exprCurrentIndex].equals("*"))
			{
				exprCurrentIndex++;
			}
			else if (exprCurrentIndex < expression.length && expression[exprCurrentIndex].equals(current))
			{
				pathCurrentIndex++;
				exprCurrentIndex++;
			}
			else if (exprCurrentIndex - 1 >= 0 && expression[exprCurrentIndex - 1].equals("*"))
			{
				pathCurrentIndex++;
			}
			else
			{
				return false;
			}
		}
		if (exprCurrentIndex > 0 && expression[exprCurrentIndex - 1].equals("*"))
		{
			return pathCurrentIndex >= path.length() && exprCurrentIndex >= expression.length;
		}
		else
		{
			return pathCurrentIndex >= path.length() && path.length() > 0;
		}
	}

	public boolean isWildcard()
	{
		return wildcard;
	}

	public boolean isIncluded()
	{
		return included;
	}

	public boolean equals(Object o)
	{
		if (this == o)
			return true;
		if (o == null || getClass() != o.getClass())
			return false;

		PathExpression that= (PathExpression) o;

		if (!Arrays.equals(expression, that.expression))
			return false;

		return true;
	}

	public int hashCode()
	{
		return (expression != null ? Arrays.hashCode(expression) : 0);
	}
}