org.linkedin.util.json.jackson.LfNSpacesIndenter.java Source code

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Here is the source code for org.linkedin.util.json.jackson.LfNSpacesIndenter.java

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/*
 * Copyright (c) 2012 Yan Pujante
 *
 * 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.linkedin.util.json.jackson;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;

import java.io.IOException;
import java.util.Arrays;

/**
 * Copied/adapted from jackson to handle N spaces instead of 2
 *
 * @author yan@pongasoft.com
 */
public class LfNSpacesIndenter implements DefaultPrettyPrinter.Indenter {
    private final int _numSpaces;

    /**
     * Constructor
     */
    public LfNSpacesIndenter(int numSpaces) {
        if (numSpaces <= 0)
            throw new IllegalArgumentException(numSpaces + " must be > 0");

        _numSpaces = numSpaces;
    }

    final static String SYSTEM_LINE_SEPARATOR;

    static {
        String lf = null;
        try {
            lf = System.getProperty("line.separator");
        } catch (Throwable t) {
            t.printStackTrace(System.err);
        } // access exception?
        SYSTEM_LINE_SEPARATOR = (lf == null) ? "\n" : lf;
    }

    final static int SPACE_COUNT = 64;
    final static char[] SPACES = new char[SPACE_COUNT];

    static {
        Arrays.fill(SPACES, ' ');
    }

    @Override
    public boolean isInline() {
        return false;
    }

    @Override
    public void writeIndentation(JsonGenerator jg, int level) throws IOException {
        jg.writeRaw(SYSTEM_LINE_SEPARATOR);
        // N spaces per level
        int numSpaces;
        // faster to add than multiply...
        switch (_numSpaces) {
        case 1:
            numSpaces = level;
            break;

        case 2:
            numSpaces = level + level;
            break;

        case 3:
            numSpaces = level + level + level;
            break;

        case 4:
            numSpaces = level + level + level + level;
            break;

        default:
            numSpaces = level * _numSpaces;
            break;
        }

        while (numSpaces > SPACE_COUNT) { // should never happen but...
            jg.writeRaw(SPACES, 0, SPACE_COUNT);
            numSpaces -= SPACES.length;
        }
        jg.writeRaw(SPACES, 0, numSpaces);
    }
}