directory.java

基于java平台的一个桌面相册,个人的电子相册...用eclipse开发的,管理并用线程做了一个浏览界面,按钮功能丰富...类似与三星的Digimax Master 可以查看相片的属性: 包括相片

/*
 * This is public domain software - that is, you can do whatever you want
 * with it, and include it software that is licensed under the GNU or the
 * BSD license, or whatever other licence you choose, including proprietary
 * closed source licenses.  I do ask that you leave this header in tact.
 *
 * If you make modifications to this code that you think would benefit the
 * wider community, please send me a copy and I'll post it on my site.
 *
 * If you make use of this code, I'd appreciate hearing about it.
 *   [e-mail]
 * Latest version of this software kept at
 *   http://drewnoakes.com/
 *
 * Created by dnoakes on 25-Nov-2002 20:30:39 using IntelliJ IDEA.
 */
package com.drew.metadata;

import com.drew.lang.Rational;

import java.io.Serializable;
import java.lang.reflect.Array;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

/**
 * Base class for all Metadata directory types with supporting methods for setting and
 * getting tag values.
 */
public abstract class Directory implements Serializable
{
    /**
     * Map of values hashed by type identifiers.
     */
    protected final HashMap _tagMap;

    /**
     * The descriptor used to interperet tag values.
     */
    protected TagDescriptor _descriptor;

    /**
     * A convenient list holding tag values in the order in which they were stored.
     * This is used for creation of an iterator, and for counting the number of
     * defined tags.
     */
    protected final List _definedTagList;

    private List _errorList;

// ABSTRACT METHODS

    /**
     * Provides the name of the directory, for display purposes.  E.g. <code>Exif</code>
     * @return the name of the directory
     */
    public abstract String getName();

    /**
     * Provides the map of tag names, hashed by tag type identifier.
     * @return the map of tag names
     */
    protected abstract HashMap getTagNameMap();

// CONSTRUCTORS

    /**
     * Creates a new Directory.
     */
    public Directory()
    {
        _tagMap = new HashMap();
        _definedTagList = new ArrayList();
    }

// VARIOUS METHODS

    /**
     * Indicates whether the specified tag type has been set.
     * @param tagType the tag type to check for
     * @return true if a value exists for the specified tag type, false if not
     */
    public boolean containsTag(int tagType)
    {
        return _tagMap.containsKey(new Integer(tagType));
    }

    /**
     * Returns an Iterator of Tag instances that have been set in this Directory.
     * @return an Iterator of Tag instances
     */
    public Iterator getTagIterator()
    {
        return _definedTagList.iterator();
    }

    /**
     * Returns the number of tags set in this Directory.
     * @return the number of tags set in this Directory
     */
    public int getTagCount()
    {
        return _definedTagList.size();
    }

    /**
     * Sets the descriptor used to interperet tag values.
     * @param descriptor the descriptor used to interperet tag values
     */
    public void setDescriptor(TagDescriptor descriptor)
    {
        if (descriptor==null) {
            throw new NullPointerException("cannot set a null descriptor");
        }
        _descriptor = descriptor;
    }

    public void addError(String message)
    {
        if (_errorList==null) {
            _errorList = new ArrayList();
        }
        _errorList.add(message);
    }

    public boolean hasErrors()
    {
        return (_errorList!=null && _errorList.size()>0);
    }

    public Iterator getErrors()
    {
        return _errorList.iterator();
    }

    public int getErrorCount()
    {
        return _errorList.size();
    }

// TAG SETTERS

    /**
     * Sets an int value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as an int
     */
    public void setInt(int tagType, int value)
    {
        setObject(tagType, new Integer(value));
    }

    /**
     * Sets a double value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a double
     */
    public void setDouble(int tagType, double value)
    {
        setObject(tagType, new Double(value));
    }

    /**
     * Sets a float value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a float
     */
    public void setFloat(int tagType, float value)
    {
        setObject(tagType, new Float(value));
    }

    /**
     * Sets an int value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a String
     */
    public void setString(int tagType, String value)
    {
        setObject(tagType, value);
    }

    /**
     * Sets an int value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a boolean
     */
    public void setBoolean(int tagType, boolean value)
    {
        setObject(tagType, new Boolean(value));
    }

    /**
     * Sets a long value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a long
     */
    public void setLong(int tagType, long value)
    {
        setObject(tagType, new Long(value));
    }

    /**
     * Sets a java.util.Date value for the specified tag.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag as a java.util.Date
     */
    public void setDate(int tagType, java.util.Date value)
    {
        setObject(tagType, value);
    }

    /**
     * Sets a Rational value for the specified tag.
     * @param tagType the tag's value as an int
     * @param rational rational number
     */
    public void setRational(int tagType, Rational rational)
    {
        setObject(tagType, rational);
    }

    /**
     * Sets a Rational array for the specified tag.
     * @param tagType the tag identifier
     * @param rationals the Rational array to store
     */
    public void setRationalArray(int tagType, Rational[] rationals)
    {
        setObjectArray(tagType, rationals);
    }

    /**
     * Sets an int array for the specified tag.
     * @param tagType the tag identifier
     * @param ints the int array to store
     */
    public void setIntArray(int tagType, int[] ints)
    {
        setObjectArray(tagType, ints);
    }

    /**
     * Sets a byte array for the specified tag.
     * @param tagType the tag identifier
     * @param bytes the byte array to store
     */
    public void setByteArray(int tagType, byte[] bytes)
    {
        setObjectArray(tagType, bytes);
    }

    /**
     * Sets a String array for the specified tag.
     * @param tagType the tag identifier
     * @param strings the String array to store
     */
    public void setStringArray(int tagType, String[] strings)
    {
        setObjectArray(tagType, strings);
    }

    /**
     * Private helper method, containing common functionality for all 'add'
     * methods.
     * @param tagType the tag's value as an int
     * @param value the value for the specified tag
     * @throws NullPointerException if value is <code>null</code>
     */
    public void setObject(int tagType, Object value)
    {
        if (value==null) {
            throw new NullPointerException("cannot set a null object");
        }

        Integer key = new Integer(tagType);
        if (!_tagMap.containsKey(key)) {
            _definedTagList.add(new Tag(tagType, this));
        }
        _tagMap.put(key, value);
    }

    /**
     * Private helper method, containing common functionality for all 'add...Array'
     * methods.
     * @param tagType the tag's value as an int
     * @param array the array of values for the specified tag
     */
    public void setObjectArray(int tagType, Object array)
    {
        // for now, we don't do anything special -- this method might be a candidate for removal once the dust settles
        setObject(tagType, array);
    }

// TAG GETTERS

    /**
     * Returns the specified tag's value as an int, if possible.
     */
    public int getInt(int tagType) throws MetadataException
    {
        Object o = getObject(tagType);
        if (o==null) {
            throw new MetadataException("Tag " + getTagName(tagType) + " has not been set -- check using containsTag() first");
        } else if (o instanceof String) {
            try {
                return Integer.parseInt((String)o);
            } catch (NumberFormatException nfe) {
                // convert the char array to an int
                String s = (String)o;
                byte[] bytes = s.getBytes();
                long val = 0;
                for (int i = 0; i < bytes.length; i++) {
                    val = val << 8;
                    val += bytes[i];
                }
                return (int)val;
            }
        } else if (o instanceof Number) {
            return ((Number)o).intValue();
        } else if (o instanceof Rational[]) {
            Rational[] rationals = (Rational[])o;
            if (rationals.length==1)
                return rationals[0].intValue();
        } else if (o instanceof byte[]) {
            byte[] bytes = (byte[])o;
            if (bytes.length==1)
                return bytes[0];
        } else if (o instanceof int[]) {
            int[] ints = (int[])o;
            if (ints.length==1)
                return ints[0];
        }
        throw new MetadataException("Tag '" + tagType + "' cannot be cast to int.  It is of type '" + o.getClass() + "'.");
    }

    // TODO get Array methods need to return cloned data, to maintain this directory's integrity

    /**
     * Gets the specified tag's value as a String array, if possible.  Only supported
     * where the tag is set as String[], String, int[], byte[] or Rational[].
     * @param tagType the tag identifier