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/*
 *  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 groovy.util;

import groovy.lang.GroovyRuntimeException;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;

/**
 * A helper class for printing indented text. This can be used stand-alone or, more commonly, from Builders.
 * 

* By default, a PrintWriter to System.out is used as the Writer, but it is possible * to change the Writer by passing a new one as a constructor argument. *

* Indention by default is 2 characters but can be changed by passing a * different value as a constructor argument. *

* The following is an example usage. Note that within a "with" block you need to * specify a parameter name so that this.println is not called instead of IndentPrinter.println: *

 * new IndentPrinter(new PrintWriter(out)).with { p ->
 *     p.printIndent()
 *     p.println('parent1')
 *     p.incrementIndent()
 *     p.printIndent()
 *     p.println('child 1')
 *     p.printIndent()
 *     p.println('child 2')
 *     p.decrementIndent()
 *     p.printIndent()
 *     p.println('parent2')
 *     p.flush()
 * }
 * 
* The above example prints this to standard output: *
 * parent1
 *   child 1
 *   child 2
 * parent2
 * 
* * @author James Strachan */ public class IndentPrinter { private int indentLevel; private String indent; private Writer out; private final boolean addNewlines; private boolean autoIndent; /** * Creates an IndentPrinter backed by a PrintWriter pointing to System.out, with an indent of two spaces. * * @see #IndentPrinter(Writer, String) */ public IndentPrinter() { this(new PrintWriter(System.out), " "); } /** * Creates an IndentPrinter backed by the supplied Writer, with an indent of two spaces. * * @param out Writer to output to * @see #IndentPrinter(Writer, String) */ public IndentPrinter(Writer out) { this(out, " "); } /** * Creates an IndentPrinter backed by the supplied Writer, * with a user-supplied String to be used for indenting. * * @param out Writer to output to * @param indent character(s) used to indent each line */ public IndentPrinter(Writer out, String indent) { this(out, indent, true); } /** * Creates an IndentPrinter backed by the supplied Writer, * with a user-supplied String to be used for indenting * and the ability to override newline handling. * * @param out Writer to output to * @param indent character(s) used to indent each line * @param addNewlines set to false to gobble all new lines (default true) */ public IndentPrinter(Writer out, String indent, boolean addNewlines) { this(out, indent, addNewlines, false); } /** * Create an IndentPrinter to the given PrintWriter * @param out Writer to output to * @param indent character(s) used to indent each line * @param addNewlines set to false to gobble all new lines (default true) * @param autoIndent set to true to make println() prepend the indent automatically (default false) */ public IndentPrinter(Writer out, String indent, boolean addNewlines, boolean autoIndent) { this.addNewlines = addNewlines; if (out == null) { throw new IllegalArgumentException("Must specify a Writer"); } this.out = out; this.indent = indent; this.autoIndent = autoIndent; } /** * Prints a string followed by an end of line character. * * @param text String to be written */ public void println(String text) { try { if(autoIndent) printIndent(); out.write(text); println(); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } /** * Prints a string. * * @param text String to be written */ public void print(String text) { try { out.write(text); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } /** * Prints a character. * * @param c char to be written */ public void print(char c) { try { out.write(c); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } /** * Prints the current indent level. */ public void printIndent() { for (int i = 0; i < indentLevel; i++) { try { out.write(indent); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } } /** * Prints an end-of-line character (if enabled via addNewLines property). * Defaults to outputting a single '\n' character but by using a custom * Writer, e.g. PlatformLineWriter, you can get platform-specific * end-of-line characters. * * @see #IndentPrinter(Writer, String, boolean) */ public void println() { if (addNewlines) { try { out.write("\n"); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } } public void incrementIndent() { ++indentLevel; } public void decrementIndent() { --indentLevel; } public int getIndentLevel() { return indentLevel; } public void setIndentLevel(int indentLevel) { this.indentLevel = indentLevel; } public boolean getAutoIndent(){ return this.autoIndent; } public void setAutoIndent(boolean autoIndent){ this.autoIndent = autoIndent; } public void flush() { try { out.flush(); } catch(IOException ioe) { throw new GroovyRuntimeException(ioe); } } }




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