code: /*
   * Copyright © 2014-2017 EntIT Software LLC, a Micro Focus company (L.P.)
   *
   * 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 io.cloudslang.runtime.impl.python.security;
  
  import java.io.StringWriter;
  import java.util.function.Supplier;
  
  /**
   * Basic implementation of a java.io.Writer than throws RuntimeException
   * when attempting to write more than 'maxChars' characters to the buffer
   */
  public class BoundedStringWriter extends StringWriter {
  
      private static final int defaultMaxChars = Integer.getInteger("jython.standardStreams.maxLength", 1000);
      private static final int nullStringLength = "null".length();
  
      private final Supplier<RuntimeException> exceptionSupplier;
      private final int maxChars;
  
      public BoundedStringWriter(Supplier<RuntimeException> exceptionSupplier) {
          super();
          this.maxChars = defaultMaxChars;
          this.exceptionSupplier = exceptionSupplier;
      }
  
      @Override
      public void write(int c) {
          validateBounds(1);
          super.write(c);
      }
  
      @Override
      public void write(char[] charArray, int off, int len) {
          if (len > 0) {
              validateBounds(len);
          }
          super.write(charArray, off, len);
      }
  
      @Override
      public void write(String str) {
          validateBounds((str == null) ? nullStringLength : str.length()); // in case of null the string "null" is added
          super.write(str);
      }
  
      @Override
      public void write(String str, int off, int len) {
          if (len > 0) {
              validateBounds(len);
          }
          super.write(str, off, len);
      }
  
      @Override
      public StringWriter append(CharSequence csq) {
          validateBounds((csq == null) ? nullStringLength : csq.length()); // in case of null the string "null" is added
          return super.append(csq);
      }
  
      @Override
      public StringWriter append(CharSequence csq, int start, int end) {
          validateBounds((csq == null) ? nullStringLength : csq.subSequence(start, end).length());
          return super.append(csq, start, end);
      }
  
      @Override
      public StringWriter append(char c) {
          validateBounds(1);
          return super.append(c);
      }
  
      private void validateBounds(int toAddNumberOfChars) {
          if ((getBuffer().length() + toAddNumberOfChars) > maxChars) {
              throw exceptionSupplier.get();
          }
      }
  
  }
  