/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * 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 org.apache.axis.components.compiler;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

/**
 * This class implements the functionality common to all Java compilers.
 * @author <a href="mailto:dims@yahoo.com">Davanum Srinivas</a>
 * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
 * @since 2.0
 */
public abstract class AbstractCompiler implements Compiler {

  /**
   * The source program filenames
   */
  protected ArrayList  fileList = new ArrayList();

  /**
   * The name of the directory containing the source program file
   */
  protected String    srcDir;

  /**
   * The name of the directory to contain the resulting object program file
   */
  protected String    destDir;

  /**
   * The classpath to be used for compilation
   */
  protected String    classpath;

  /**
   * The encoding of the source program or <code>null</code> to use the
   * platform's default encoding
   */
  protected String    encoding = null;

  /**
   * The input stream to output compilation errors
   */
  protected InputStream errors;

  /**
   * Add the name of the file containing the source program to the file list
   *
   * @param file The name of the file containing the source program
   */
  public void addFile(String file) {
    this.fileList.add(file);
  }

  /**
   * Set the name of the directory containing the source program file
   *
   * @param srcDir The name of the directory containing the source program file
   */
  public void setSource(String srcDir) {
    this.srcDir = srcDir;
  }

  /**
   * Set the name of the directory to contain the resulting object program file
   *
   * @param destDir The name of the directory to contain the resulting object
   * program file
   */
  public void setDestination(String destDir) {
      this.destDir = destDir;
  }

  /**
   * Set the classpath to be used for this compilation
   *
   * @param classpath The classpath to be used for this compilation
   */
  public void setClasspath(String classpath) {
    this.classpath = classpath;
  }

  /**
   * Set the encoding of the input source file or <code>null</code> to use the
   * platform's default encoding
   *
   * @param encoding The encoding of the input source file or <code>null</code>
   * to use the platform's default encoding
   */
  public void setEncoding(String encoding) {
    this.encoding = encoding;
  }

  /**
   * Return the list of errors generated by this compilation
   *
   * @return The list of errors generated by this compilation
   * @exception IOException If an error occurs during message collection
   */
  public List getErrors() throws IOException {
    return parseStream(new BufferedReader(new InputStreamReader(errors)));
  }

  /**
   * Parse the compiler error stream to produce a list of
   * <code>CompilerError</code>s
   *
   * @param errors The error stream
   * @return The list of compiler error messages
   * @exception IOException If an error occurs during message collection
   */
  protected abstract List parseStream(BufferedReader errors)
      throws IOException;

  /**
   * Fill the arguments taken by the Java compiler
   *
   * @param arguments The list of compilation arguments
   * @return The prepared list of compilation arguments
   */
  protected List fillArguments(List arguments) {
    // destination directory
    arguments.add("-d");
    arguments.add(destDir);

    // classpath
    arguments.add("-classpath");
    arguments.add(classpath);

    // sourcepath
    if(srcDir != null) {
        arguments.add("-sourcepath");
        arguments.add(srcDir);
    }

    // add optimization (for what is worth)
    arguments.add("-O");

    // add debug option
    arguments.add("-g");

    // add encoding if set
    if (encoding != null) {
      arguments.add("-encoding");
      arguments.add(encoding);
    }

    return arguments;
  }

  /**
   * Copy arguments to a string array
   *
   * @param arguments The compiler arguments
   * @return A string array containing compilation arguments
   */
  protected String[] toStringArray(List arguments) {
    int    i;
    String[] args = new String[arguments.size() + fileList.size()];

    for (i = 0; i < arguments.size(); i++) {
      args[i] = (String) arguments.get(i);
    }

    for (int j=0; j < fileList.size(); i++,j++) {
        args[i] = (String)fileList.get(j);
    }
    return args;
  }
}