IndentingPrintWriter.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.io;

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

/**
 * Extend PrintWriter to automatically indent new lines.
 */
public class IndentingPrintWriter extends PrintWriter {

    private String indent;
    private int indentLevel;
    private boolean needsIndent;

    public static String DEFAULT_INDENT = "\t";

    /**
     * Construct a writer that indents with tabs.
     */
    public IndentingPrintWriter(Writer out) {
        this(out, DEFAULT_INDENT);
    }

    /**
     * Construct a writer that indents with the specified string.
     */
    public IndentingPrintWriter(Writer out, String indent) {
        super(out);
        this.indent = indent;
        this.indentLevel = 0;
        this.needsIndent = true;
    }

    /**
     * Set flag so following line is indented.
     */
    public void println() {
        synchronized (this.lock) {
            super.println();
            this.needsIndent = true;
        }
    }

    /**
     * Print the appropriate indent.
     */
    private void printIndent() {
        if (this.needsIndent) {
            this.needsIndent = false;
            for (int i = this.indentLevel; i-- > 0; ) {
                this.print(this.indent);
            }
        }
    }

    /**
     * Write a portion of an array of characters.
     */
    public void write(char buf[], int off, int len) {
        synchronized (this.lock) {
            this.printIndent();
            super.write(buf, off, len);
        }
    }

    /**
     * Write a single character.
     */
    public void write(int c) {
        synchronized (this.lock) {
            this.printIndent();
            super.write(c);
        }
    }

    /**
     * Write a portion of a string.
     */
    public void write(String s, int off, int len) {
        synchronized (this.lock) {
            this.printIndent();
            super.write(s, off, len);
        }
    }

    /**
     * Bump the indent level.
     */
    public void indent() {
        this.incrementIndentLevel();
    }

    /**
     * Decrement the indent level.
     */
    public void undent() {
        this.decrementIndentLevel();
    }

    /**
     * Bump the indent level.
     */
    public void incrementIndentLevel() {
        synchronized (this.lock) {
            this.indentLevel++;
        }
    }

    /**
     * Decrement the indent level.
     */
    public void decrementIndentLevel() {
        synchronized (this.lock) {
            this.indentLevel--;
        }
    }

    /**
     * Return the current indent level.
     */
    public int getIndentLevel() {
        return this.indentLevel;
    }

    /**
     * Allow the indent level to be set directly.
     */
    public void setIndentLevel(int indentLevel) {
        synchronized (this.lock) {
            this.indentLevel = indentLevel;
        }
    }

}