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/*
 * $Id: PdfDictionary.java 3762 2009-03-06 16:53:44Z blowagie $
 *
 * Copyright 1999, 2000, 2001, 2002 Bruno Lowagie
 *
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the License.
 *
 * The Original Code is 'iText, a free JAVA-PDF library'.
 *
 * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
 * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
 * All Rights Reserved.
 * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
 * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
 *
 * Contributor(s): all the names of the contributors are added in the source code
 * where applicable.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
 * provisions of LGPL are applicable instead of those above.  If you wish to
 * allow use of your version of this file only under the terms of the LGPL
 * License and not to allow others to use your version of this file under
 * the MPL, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the LGPL.
 * If you do not delete the provisions above, a recipient may use your version
 * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MPL as stated above or under the terms of the GNU
 * Library General Public License as published by the Free Software Foundation;
 * either version 2 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
 * details.
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * http://www.lowagie.com/iText/
 */

package com.lowagie.text.pdf;

import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * PdfDictionary is the Pdf dictionary object.
 * 
 * A dictionary is an associative table containing pairs of objects.
 * The first element of each pair is called the key and the second
 * element is called the value.
 * Unlike dictionaries in the PostScript language, a key must be a
 * PdfName.
 * A value can be any kind of PdfObject, including a dictionary.
 * A dictionary is generally used to collect and tie together the attributes
 * of a complex object, with each key-value pair specifying the name and value
 * of an attribute.

 * A dictionary is represented by two left angle brackets (<<), followed by a
 * sequence of key-value pairs, followed by two right angle brackets (>>).

 * This object is described in the 'Portable Document Format Reference Manual
 * version 1.7' section 3.2.6 (page 59-60).
 * 
 *
 * @see PdfObject
 * @see PdfName
 * @see BadPdfFormatException
 */
public class PdfDictionary extends PdfObject {

    // CONSTANTS

    /** This is a possible type of dictionary */
    public static final PdfName FONT = PdfName.FONT;

    /** This is a possible type of dictionary */
    public static final PdfName OUTLINES = PdfName.OUTLINES;

    /** This is a possible type of dictionary */
    public static final PdfName PAGE = PdfName.PAGE;

    /** This is a possible type of dictionary */
    public static final PdfName PAGES = PdfName.PAGES;

    /** This is a possible type of dictionary */
    public static final PdfName CATALOG = PdfName.CATALOG;

    // CLASS VARIABLES

    /** This is the type of this dictionary */
    private PdfName dictionaryType = null;

    /** This is the hashmap that contains all the values and keys of the dictionary */
    protected HashMap hashMap;

    // CONSTRUCTORS

    /**
     * Constructs an empty PdfDictionary-object.
     */
    public PdfDictionary() {
        super(DICTIONARY);
        hashMap = new HashMap();
    }

    /**
     * Constructs a PdfDictionary-object of a certain type.
     *
     * @param type a PdfName
     */
    public PdfDictionary(PdfName type) {
        this();
        dictionaryType = type;
        put(PdfName.TYPE, dictionaryType);
    }

    // METHODS OVERRIDING SOME PDFOBJECT METHODS

    /**
     * Writes the PDF representation of this PdfDictionary as an
     * array of byte to the given OutputStream.
     *
     * @param writer for backwards compatibility
     * @param os the OutputStream to write the bytes to.
     * @throws IOException
     */
    public void toPdf(PdfWriter writer, OutputStream os) throws IOException {
        os.write('<');
        os.write('<');
        // loop over all the object-pairs in the HashMap

        for (Map.Entry entry : hashMap.entrySet()) {
            PdfName key = entry.getKey();
            PdfObject value = entry.getValue();
            key.toPdf(writer, os);
            int type = value.type();
            if (type != PdfObject.ARRAY && type != PdfObject.DICTIONARY && type != PdfObject.NAME && type != PdfObject.STRING) {
                os.write(' ');
            }
            value.toPdf(writer, os);
        }
        os.write('>');
        os.write('>');
    }

    /**
     * Returns a string representation of this PdfDictionary.
     *
     * The string doesn't contain any of the content of this dictionary.
     * Rather the string "dictionary" is returned, possibly followed by the
     * type of this PdfDictionary, if set.
     *
     * @return the string representation of this PdfDictionary
     * @see com.lowagie.text.pdf.PdfObject#toString()
     */
    public String toString() {
        if (get(PdfName.TYPE) == null) {
            return "Dictionary";
        }
        return "Dictionary of type: " + get(PdfName.TYPE);
    }

    // DICTIONARY CONTENT METHODS

    /**
     * Associates the specified PdfObject as value with
     * the specified PdfName as key in this map.
     *
     * If the map previously contained a mapping for this key, the
     * old value is replaced. If the value is
     * null or PdfNull the key is deleted.
     *
     * @param key a PdfName
     * @param object the PdfObject to be associated with the
     *        key
     */
    public void put(PdfName key, PdfObject object) {
        if (object == null || object.isNull()) {
            remove(key);
        } else {
            hashMap.put(key, object);
        }
    }

    /**
     * Associates the specified PdfObject as value to the
     * specified PdfName as key in this map.
     *
     * If the value is a PdfNull, it is treated just as
     * any other PdfObject. If the value is
     * null however nothing is done.
     *
     * @param key a PdfName
     * @param value the PdfObject to be associated to the
     *        key
     */
    public void putEx(PdfName key, PdfObject value) {
        if (value == null) {
            return;
        }
        put(key, value);
    }

    /**
     * Copies all of the mappings from the specified PdfDictionary
     * to this PdfDictionary.
     *
     * These mappings will replace any mappings previously contained in this
     * PdfDictionary.
     *
     * @param dic The PdfDictionary with the mappings to be
     *        copied over
     */
    public void putAll(PdfDictionary dic) {
        hashMap.putAll(dic.hashMap);
    }

    /**
     * Removes a PdfObject and its key from the
     * PdfDictionary.
     *
     * @param key a PdfName
     */
    public void remove(PdfName key) {
        hashMap.remove(key);
    }

    /**
     * Returns the PdfObject associated to the specified
     * key.
     *
     * @param key a PdfName
     * @return the PdfObject previously associated to the
     *         key
     */
    public PdfObject get(PdfName key) {
        return hashMap.get(key);
    }

    /**
     * Returns the PdfObject associated to the specified
     * key, resolving a possible indirect reference to a direct
     * object.
     *
     * This method will never return a PdfIndirectReference
     * object.
     *
     * @param key A key for the PdfObject to be returned
     * @return A direct PdfObject or null
     */
    public PdfObject getDirectObject(PdfName key) {
        return PdfReader.getPdfObject(get(key));
    }

    /**
     * Get all keys that are set.
     *
     * @return true if it is, otherwise false.
     */
    public Set getKeys() {
        return hashMap.keySet();
    }

    /**
     * Returns the number of key-value mappings in this
     * PdfDictionary.
     *
     * @return the number of key-value mappings in this
     *         PdfDictionary.
     */
    public int size() {
        return hashMap.size();
    }

    /**
     * Returns true if this PdfDictionary contains a
     * mapping for the specified key.
     *
     * @return true if the key is set, otherwise false.
     */
    public boolean contains(PdfName key) {
        return hashMap.containsKey(key);
    }

    // DICTIONARY TYPE METHODS

    /**
     * Checks if a Dictionary is of the type FONT.
     *
     * @return true if it is, otherwise false.
     */
    public boolean isFont() {
        return FONT.equals(dictionaryType);
    }

    /**
     * Checks if a Dictionary is of the type PAGE.
     *
     * @return true if it is, otherwise false.
     */
    public boolean isPage() {
        return PAGE.equals(dictionaryType);
    }

    /**
     * Checks if a Dictionary is of the type PAGES.
     *
     * @return true if it is, otherwise false.
     */
    public boolean isPages() {
        return PAGES.equals(dictionaryType);
    }

    /**
     * Checks if a Dictionary is of the type CATALOG.
     *
     * @return true if it is, otherwise false.
     */
    public boolean isCatalog() {
        return CATALOG.equals(dictionaryType);
    }

    /**
     * Checks if a Dictionary is of the type OUTLINES.
     *
     * @return true if it is, otherwise false.
     */
    public boolean isOutlineTree() {
        return OUTLINES.equals(dictionaryType);
    }

    // OTHER METHODS

    public void merge(PdfDictionary other) {
        hashMap.putAll(other.hashMap);
    }

    public void mergeDifferent(PdfDictionary other) {
        for (Map.Entry entry : other.hashMap.entrySet()) {
            PdfName key = entry.getKey();
            PdfObject value = entry.getValue();
            if (!hashMap.containsKey(key)) {
                hashMap.put(key, value);
            }
        }
    }

    // DOWNCASTING GETTERS
    // @author Mark A Storer (2/17/06)

    /**
     * Returns a PdfObject as a PdfDictionary,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfDictionary, it is cast down and returned as
     * such. Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfDictionary object,
     *         or null
     */
    public PdfDictionary getAsDict(PdfName key) {
        PdfDictionary dict = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isDictionary()) {
            dict = (PdfDictionary) orig;
        }
        return dict;
    }

    /**
     * Returns a PdfObject as a PdfArray,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfArray, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfArray object,
     *         or null
     */
    public PdfArray getAsArray(PdfName key) {
        PdfArray array = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isArray())
            array = (PdfArray) orig;
        return array;
    }

    /**
     * Returns a PdfObject as a PdfStream,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfStream, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfStream object,
     *         or null
     */
    public PdfStream getAsStream(PdfName key) {
        PdfStream stream = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isStream()) {
            stream = (PdfStream) orig;
        }
        return stream;
    }

    /**
     * Returns a PdfObject as a PdfString,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfString, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfString object,
     *         or null
     */
    public PdfString getAsString(PdfName key) {
        PdfString string = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isString()) {
            string = (PdfString) orig;
        }
        return string;
    }

    /**
     * Returns a PdfObject as a PdfNumber,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfNumber, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfNumber object,
     *         or null
     */
    public PdfNumber getAsNumber(PdfName key) {
        PdfNumber number = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isNumber()) {
            number = (PdfNumber) orig;
        }
        return number;
    }

    /**
     * Returns a PdfObject as a PdfName,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfName, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfName object,
     *         or null
     */
    public PdfName getAsName(PdfName key) {
        PdfName name = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isName()) {
            name = (PdfName) orig;
        }
        return name;
    }

    /**
     * Returns a PdfObject as a PdfBoolean,
     * resolving indirect references.
     *
     * The object associated with the PdfName given is retrieved
     * and resolved to a direct object.
     * If it is a PdfBoolean, it is cast down and returned as such.
     * Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfBoolean object,
     *         or null
     */
    public PdfBoolean getAsBoolean(PdfName key) {
        PdfBoolean bool = null;
        PdfObject orig = getDirectObject(key);
        if (orig != null && orig.isBoolean()) {
            bool = (PdfBoolean) orig;
        }
        return bool;
    }

    /**
     * Returns a PdfObject as a PdfIndirectReference.
     *
     * The object associated with the PdfName given is retrieved
     * If it is a PdfIndirectReference, it is cast down and returned
     * as such. Otherwise null is returned.
     *
     * @param key A PdfName
     * @return the associated PdfIndirectReference object,
     *         or null
     */
    public PdfIndirectReference getAsIndirectObject(PdfName key) {
        PdfIndirectReference ref = null;
        // not getDirect this time.
        PdfObject orig = get(key);
        if (orig != null && orig.isIndirect()) {
            ref = (PdfIndirectReference) orig;
        }
        return ref;
    }
}