content: /*
   *  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
   *
   *      https://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 org.apache.tools.ant.types.resources;
  
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.Stack;
  
  import org.apache.tools.ant.BuildException;
  import org.apache.tools.ant.Project;
  import org.apache.tools.ant.types.DataType;
  import org.apache.tools.ant.types.Resource;
  import org.apache.tools.ant.types.ResourceCollection;
  import org.apache.tools.ant.util.ConcatResourceInputStream;
  import org.apache.tools.ant.util.LineTokenizer;
  import org.apache.tools.ant.util.Tokenizer;
  
  /**
   * ResourceCollection consisting of StringResources gathered from tokenizing
   * another ResourceCollection with a Tokenizer implementation.
   * @since Ant 1.7
   */
  public class Tokens extends BaseResourceCollectionWrapper {
  
      private Tokenizer tokenizer;
      private String encoding;
  
      /**
       * Sort the contained elements.
       * @return a Collection of Resources.
       */
      protected synchronized Collection<Resource> getCollection() {
          ResourceCollection rc = getResourceCollection();
          if (rc.isEmpty()) {
              return Collections.emptySet();
          }
          if (tokenizer == null) {
              tokenizer = new LineTokenizer();
          }
          try (ConcatResourceInputStream cat = new ConcatResourceInputStream(rc);
                  InputStreamReader rdr = new InputStreamReader(cat,
                      encoding == null ? Charset.defaultCharset()
                          : Charset.forName(encoding))) {
              cat.setManagingComponent(this);
              List<Resource> result = new ArrayList<>();
              for (String s = tokenizer.getToken(rdr); s != null; s =
                  tokenizer.getToken(rdr)) {
                  // do not send the Project to the constructor of StringResource, since
                  // the semantics of that constructor clearly state that property value
                  // replacement takes place on the passed string value. We don't want
                  // that to happen.
                  final StringResource resource = new StringResource(s);
                  resource.setProject(getProject());
                  result.add(resource);
              }
              return result;
          } catch (IOException e) {
              throw new BuildException("Error reading tokens", e);
          }
      }
  
      /**
       * Set the encoding used to create the tokens.
       * @param encoding the encoding to use.
       */
      public synchronized void setEncoding(String encoding) {
          this.encoding = encoding;
      }
  
      /**
       * Add the nested Tokenizer to this Tokens ResourceCollection.
       * A LineTokenizer will be used by default.
       * @param tokenizer the tokenizer to add.
       */
      public synchronized void add(Tokenizer tokenizer) {
          if (isReference()) {
              throw noChildrenAllowed();
          }
          if (this.tokenizer != null) {
              throw new BuildException("Only one nested tokenizer allowed.");
          }
          this.tokenizer = tokenizer;
          setChecked(false);
      }
  
      /**
       * Overrides the BaseResourceCollectionContainer version
       * to check the nested Tokenizer.
       * @param stk the stack of data types to use (recursively).
       * @param p   the project to use to dereference the references.
       * @throws BuildException on error.
       */
      @Override
      protected synchronized void dieOnCircularReference(Stack<Object> stk, Project p)
          throws BuildException {
          if (isChecked()) {
              return;
          }
  
          // check nested collection
          super.dieOnCircularReference(stk, p);
  
          if (!isReference()) {
              if (tokenizer instanceof DataType) {
                  pushAndInvokeCircularReferenceCheck((DataType) tokenizer, stk,
                                                      p);
              }
              setChecked(true);
          }
      }
  
  }
  