com.davidbracewell.io.resource.ResourceChildIterator Maven / Gradle / Ivy

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A set of utilities and tools to speed up and ease programming in Java.

There is a newer version: 0.5

/*
 * (c) 2005 David B. Bracewell
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.davidbracewell.io.resource;

import com.google.common.collect.Lists;
import lombok.NonNull;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.regex.Pattern;

/**
 * @author David B. Bracewell
 */
public class ResourceChildIterator implements Iterator {

  private final Pattern filePattern;
  private final Queue queue = Lists.newLinkedList();
  private final boolean recursive;

  /**
   * Instantiates a new Child iterator.
   *
   * @param startingPoint the starting point
   * @param filePattern   the file pattern
   * @param recursive     the recursive
   */
  public ResourceChildIterator(@NonNull Resource startingPoint, @NonNull Pattern filePattern, boolean recursive) {
    this.filePattern = filePattern;
    queue.addAll(startingPoint.getChildren(filePattern, false));
    this.recursive = recursive;
    advance();
  }

  private void advance() {
    if (queue.isEmpty()) {
      return;
    }
    if (queue.peek().isDirectory()) {
      if (recursive) {
        queue.addAll(queue.peek().getChildren(filePattern, false));
      }
    }
  }

  @Override
  public boolean hasNext() {
    return !queue.isEmpty();
  }

  @Override
  public Resource next() {
    if (queue.isEmpty()) {
      throw new NoSuchElementException();
    }
    Resource next = queue.remove();
    advance();
    return next;
  }

  @Override
  public void remove() {
    throw new UnsupportedOperationException();
  }
}//END OF ResourceChildIterator