

package net.mapeadores.util.json;

import java.io.IOException;


/*
 Copyright (c) 2006 JSON.org

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 The Software shall be used for Good, not Evil.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */

/**
 * JSONWriter provides a quick and convenient way of producing JSON text. The
 * texts produced strictly conform to JSON syntax rules. No whitespace is added,
 * so the results are ready for transmission or storage. Each instance of
 * JSONWriter can produce one JSON text.
 * <p>
 * A JSONWriter instance provides a <code>value</code> method for appending
 * values to the text, and a <code>key</code> method for adding keys before
 * values in objects. There are <code>array</code> and <code>endArray</code>
 * methods that make and bound array values, and <code>object</code> and
 * <code>endObject</code> methods which make and bound object values. All of
 * these methods return the JSONWriter instance, permitting a cascade style. For
 * example,
 * <pre>
 * new JSONWriter(myWriter)
 *     .object()
 *         .key("JSON")
 *         .value("Hello, World!")
 *     .endObject();</pre> which writes
 * <pre>
 * {"JSON":"Hello, World!"}</pre>
 * <p>
 * The first method called must be <code>array</code> or <code>object</code>.
 * There are no methods for adding commas or colons. JSONWriter adds them for
 * you. Objects and arrays can be nested up to 20 levels deep.
 * <p>
 * This can sometimes be easier than using a JSONObject to build a string.
 *
 * @author JSON.org
 * @version 2008-09-22
 */
/**
 * Modification Vincent Calame (2010-03-10) : Writer => Appendable
 */
public class JSONWriter {

    private static final int maxdepth = 20;
    /**
     * The comma flag determines if a comma should be output before the next
     * value.
     */
    private boolean comma;
    /**
     * The current mode. Values: 'a' (array), 'd' (done), 'i' (initial), 'k'
     * (key), 'o' (object).
     */
    protected char mode;
    /**
     * The object/array stack.
     */
    private final JSONObject stack[];
    /**
     * The stack top index. A value of 0 indicates that the stack is empty.
     */
    private int top;
    /**
     * The appendable that will receive the output.
     */
    protected Appendable appendable;

    /**
     * Make a fresh JSONWriter. It can be used to build one JSON text.
     */
    public JSONWriter(Appendable a) {
        this.comma = false;
        this.mode = 'i';
        this.stack = new JSONObject[maxdepth];
        this.top = 0;
        this.appendable = a;
    }

    /**
     * Append a value.
     *
     * @param s A string value.
     * @return this
     * @throws JSONException If the value is out of sequence.
     */
    private JSONWriter append(String s) throws IOException {
        if (s == null) {
            throw new JSONException("Null pointer");
        }
        if (this.mode == 'o' || this.mode == 'a') {
            if (this.comma && this.mode == 'a') {
                this.appendable.append(',');
            }
            this.appendable.append(s);
            if (this.mode == 'o') {
                this.mode = 'k';
            }
            this.comma = true;
            return this;
        }
        throw new JSONException("Value out of sequence.");
    }

    /**
     * Begin appending a new array. All values until the balancing
     * <code>endArray</code> will be appended to this array. The
     * <code>endArray</code> method must be called to mark the array's end.
     *
     * @return this
     * @throws JSONException If the nesting is too deep, or if the object is
     * started in the wrong place (for example as a key or after the end of the
     * outermost array or object).
     */
    public JSONWriter array() throws IOException {
        if (this.mode == 'i' || this.mode == 'o' || this.mode == 'a') {
            this.push(null);
            this.append("[");
            this.comma = false;
            return this;
        }
        throw new JSONException("Misplaced array.");
    }

    /**
     * End something.
     *
     * @param m Mode
     * @param c Closing character
     * @return this
     * @throws JSONException If unbalanced.
     */
    private JSONWriter end(char m, char c) throws IOException {
        if (this.mode != m) {
            throw new JSONException(m == 'o' ? "Misplaced endObject."
                    : "Misplaced endArray.");
        }
        this.pop(m);
        this.appendable.append(c);
        this.comma = true;
        return this;
    }

    /**
     * End an array. This method most be called to balance calls to
     * <code>array</code>.
     *
     * @return this
     * @throws JSONException If incorrectly nested.
     */
    public JSONWriter endArray() throws IOException {
        return this.end('a', ']');
    }

    /**
     * End an object. This method most be called to balance calls to
     * <code>object</code>.
     *
     * @return this
     * @throws JSONException If incorrectly nested.
     */
    public JSONWriter endObject() throws IOException {
        return this.end('k', '}');
    }

    /**
     * Append a key. The key will be associated with the next value. In an
     * object, every value must be preceded by a key.
     *
     * @param s A key string.
     * @return this
     * @throws JSONException If the key is out of place. For example, keys do
     * not belong in arrays or if the key is null.
     */
    public JSONWriter key(String s) throws IOException {
        if (s == null) {
            throw new JSONException("Null key.");
        }
        if (this.mode == 'k') {
            stack[top - 1].putOnce(s, Boolean.TRUE);
            if (this.comma) {
                this.appendable.append(',');
            }
            this.appendable.append(JSONObject.quote(s));
            this.appendable.append(':');
            this.comma = false;
            this.mode = 'o';
            return this;
        }
        throw new JSONException("Misplaced key.");
    }

    /**
     * Begin appending a new object. All keys and values until the balancing
     * <code>endObject</code> will be appended to this object. The
     * <code>endObject</code> method must be called to mark the object's end.
     *
     * @return this
     * @throws JSONException If the nesting is too deep, or if the object is
     * started in the wrong place (for example as a key or after the end of the
     * outermost array or object).
     */
    public JSONWriter object() throws IOException {
        if (this.mode == 'i') {
            this.mode = 'o';
        }
        if (this.mode == 'o' || this.mode == 'a') {
            this.append("{");
            this.push(new JSONObject());
            this.comma = false;
            return this;
        }
        throw new JSONException("Misplaced object.");

    }

    /**
     * Pop an array or object scope.
     *
     * @param c The scope to close.
     * @throws JSONException If nesting is wrong.
     */
    private void pop(char c) {
        if (this.top <= 0) {
            throw new JSONException("Nesting error.");
        }
        char m = this.stack[this.top - 1] == null ? 'a' : 'k';
        if (m != c) {
            throw new JSONException("Nesting error.");
        }
        this.top -= 1;
        this.mode = this.top == 0 ? 'd' : this.stack[this.top - 1] == null ? 'a' : 'k';
    }

    /**
     * Push an array or object scope.
     *
     * @param c The scope to open.
     * @throws JSONException If nesting is too deep.
     */
    private void push(JSONObject jo) {
        if (this.top >= maxdepth) {
            throw new JSONException("Nesting too deep.");
        }
        this.stack[this.top] = jo;
        this.mode = jo == null ? 'a' : 'k';
        this.top += 1;
    }

    /**
     * Append either the value <code>true</code> or the value
     * <code>false</code>.
     *
     * @param b A boolean.
     * @return this
     * @throws JSONException
     */
    public JSONWriter value(boolean b) throws IOException {
        return this.append(b ? "true" : "false");
    }

    /**
     * Append a double value.
     *
     * @param d A double.
     * @return this
     * @throws JSONException If the number is not finite.
     */
    public JSONWriter value(double d) throws IOException {
        return this.value(Double.valueOf(d));
    }

    /**
     * Append a long value.
     *
     * @param l A long.
     * @return this
     * @throws JSONException
     */
    public JSONWriter value(long l) throws IOException {
        return this.append(Long.toString(l));
    }

    /**
     * Append an object value.
     *
     * @param o The object to append. It can be null, or a Boolean, Number,
     * String, JSONObject, or JSONArray, or an object with a toJSONString()
     * method.
     * @return this
     * @throws JSONException If the value is out of sequence.
     */
    public JSONWriter value(Object o) throws IOException {
        return this.append(JSONObject.valueToString(o));
    }

}
