org.neogroup.warp.controllers.formatters.JsonFormatter Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of NeoGroup-Warp Show documentation
Simple web framework
There is a newer version: 1.4.3
package org.neogroup.warp.controllers.formatters;

import org.neogroup.warp.data.DataObject;
import org.neogroup.warp.utils.Introspection;

import java.io.StringWriter;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class JsonFormatter extends Formatter {

    private static final String JSON_NULL = "null";
    private static final char JSON_ARRAY_START_CHAR = '[';
    private static final char JSON_ARRAY_END_CHAR = ']';
    private static final char JSON_OBJECT_START_CHAR = '{';
    private static final char JSON_OBJECT_END_CHAR = '}';
    private static final char JSON_DOUBLE_COLON_CHAR = '"';
    private static final char JSON_ELEMENT_SEPARATOR_CHAR = ',';
    private static final char JSON_OBJECT_KEY_VALUE_SEPARATOR_CHAR = ':';

    @Override
    public String format(Object object) {
        StringWriter writer = new StringWriter();
        write(object, writer);
        return writer.toString();
    }

    private void write (Object object, StringWriter writer) {
        if (object == null) {
            writeNull(writer);
        } else if ((object instanceof Number)) {
            writeNumber((Number) object, writer);
        } else if (object instanceof Boolean) {
            writeBoolean((Boolean) object, writer);
        } else if (object instanceof CharSequence) {
            writeString((CharSequence) object, writer);
        } else if (object instanceof DataObject) {
            writeDataObject((DataObject) object, writer);
        } else if (object.getClass().isArray()) {
            writeArray((Object[]) object, writer);
        } else if (object instanceof Iterable) {
            writeIterable((Iterable) object, writer);
        } else if (object instanceof Map) {
            writeMap((Map) object, writer);
        } else if (object instanceof Date) {
            writeDate((Date) object, writer);
        } else {
            writeObject(object, writer);
        }
    }

    private void writeNull (StringWriter writer) {
        writer.append(JSON_NULL);
    }

    private void writeNumber (Number number, StringWriter writer) {
        writer.append(number.toString());
    }

    private void writeBoolean (Boolean bool, StringWriter writer) {
        writer.append(bool.toString());
    }

    private void writeDate (Date date, StringWriter writer) {
        writer.append(JSON_DOUBLE_COLON_CHAR);
        writer.append(date.toString());
        writer.append(JSON_DOUBLE_COLON_CHAR);
    }

    private void writeString (CharSequence string, StringWriter writer) {
        writer.append(JSON_DOUBLE_COLON_CHAR);
        writer.append(string);
        writer.append(JSON_DOUBLE_COLON_CHAR);
    }

    private void writeObject(Object object, StringWriter writer) {
        try {
            Class objectClass = object.getClass();
            writer.append(JSON_OBJECT_START_CHAR);
            boolean isFirst = true;
            List properties = Introspection.getProperties(objectClass);
            for (Introspection.Property property : properties) {
                if (!isFirst) {
                    writer.append(JSON_ELEMENT_SEPARATOR_CHAR);
                }
                writer.append(JSON_DOUBLE_COLON_CHAR);
                writer.append(property.getName());
                writer.append(JSON_DOUBLE_COLON_CHAR);
                writer.append(JSON_OBJECT_KEY_VALUE_SEPARATOR_CHAR);
                write(property.getValue(object), writer);
                isFirst = false;
            }
            writer.append(JSON_OBJECT_END_CHAR);
        }
        catch (Throwable throwable) {
            throw new RuntimeException(throwable);
        }
    }

    private void writeDataObject (DataObject dataObject, StringWriter writer) {
        writer.append(JSON_OBJECT_START_CHAR);
        boolean isFirst = true;
        Set keys = dataObject.properties();
        for (String key : keys) {
            if (!isFirst) {
                writer.append(JSON_ELEMENT_SEPARATOR_CHAR);
            }
            writer.append(JSON_DOUBLE_COLON_CHAR);
            writer.append(key);
            writer.append(JSON_DOUBLE_COLON_CHAR);
            writer.append(JSON_OBJECT_KEY_VALUE_SEPARATOR_CHAR);
            write(dataObject.get(key), writer);
            isFirst = false;
        }
        writer.append(JSON_OBJECT_END_CHAR);
    }

    private void writeMap (Map map, StringWriter writer) {
        writer.append(JSON_OBJECT_START_CHAR);
        boolean isFirst = true;
        for (Object key : map.keySet()) {
            if (!isFirst) {
                writer.append(JSON_ELEMENT_SEPARATOR_CHAR);
            }
            writer.append(JSON_DOUBLE_COLON_CHAR);
            writer.append(key.toString());
            writer.append(JSON_DOUBLE_COLON_CHAR);
            writer.append(JSON_OBJECT_KEY_VALUE_SEPARATOR_CHAR);
            write(map.get(key), writer);
            isFirst = false;
        }
        writer.append(JSON_OBJECT_END_CHAR);
    }

    private void writeArray(Object[] objects, StringWriter writer) {
        writer.append(JSON_ARRAY_START_CHAR);
        boolean isFirst = true;
        for (Object object : objects) {
            if (!isFirst) {
                writer.append(JSON_ELEMENT_SEPARATOR_CHAR);
            }
            write(object, writer);
            isFirst = false;
        }
        writer.append(JSON_ARRAY_END_CHAR);
    }

    private void writeIterable(Iterable iterable, StringWriter writer) {
        writer.append(JSON_ARRAY_START_CHAR);
        boolean isFirst = true;
        for (Object object : iterable) {
            if (!isFirst) {
                writer.append(JSON_ELEMENT_SEPARATOR_CHAR);
            }
            write(object, writer);
            isFirst = false;
        }
        writer.append(JSON_ARRAY_END_CHAR);
    }
}