/*
* Copyright 2002-2016 Drew Noakes
*
* 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.
*
* More information about this project is available at:
*
* https://drewnoakes.com/code/exif/
* https://github.com/drewnoakes/metadata-extractor
*/
package com.drew.metadata;
import com.drew.lang.annotations.NotNull;
import com.drew.lang.annotations.Nullable;
/**
* Models a particular tag within a {@link com.drew.metadata.Directory} and provides methods for obtaining its value.
* Immutable.
*
* @author Drew Noakes https://drewnoakes.com
*/
public class Tag
{
private final int _tagType;
@NotNull
private final Directory _directory;
public Tag(int tagType, @NotNull Directory directory)
{
_tagType = tagType;
_directory = directory;
}
/**
* Gets the tag type as an int
*
* @return the tag type as an int
*/
public int getTagType()
{
return _tagType;
}
/**
* Gets the tag type in hex notation as a String with padded leading
* zeroes if necessary (i.e. <code>0x100e</code>).
*
* @return the tag type as a string in hexadecimal notation
*/
@NotNull
public String getTagTypeHex()
{
return String.format("0x%04x", _tagType);
}
/**
* Get a description of the tag's value, considering enumerated values
* and units.
*
* @return a description of the tag's value
*/
@Nullable
public String getDescription()
{
return _directory.getDescription(_tagType);
}
/**
* Get whether this tag has a name.
*
* If <code>true</code>, it may be accessed via {@link #getTagName}.
* If <code>false</code>, {@link #getTagName} will return a string resembling <code>"Unknown tag (0x1234)"</code>.
*
* @return whether this tag has a name
*/
@NotNull
public boolean hasTagName()
{
return _directory.hasTagName(_tagType);
}
/**
* Get the name of the tag, such as <code>Aperture</code>, or
* <code>InteropVersion</code>.
*
* @return the tag's name
*/
@NotNull
public String getTagName()
{
return _directory.getTagName(_tagType);
}
/**
* Get the name of the {@link com.drew.metadata.Directory} in which the tag exists, such as
* <code>Exif</code>, <code>GPS</code> or <code>Interoperability</code>.
*
* @return name of the {@link com.drew.metadata.Directory} in which this tag exists
*/
@NotNull
public String getDirectoryName()
{
return _directory.getName();
}
/**
* A basic representation of the tag's type and value. EG: <code>[Exif IFD0] FNumber - f/2.8</code>.
*
* @return the tag's type and value
*/
@Override
@NotNull
public String toString()
{
String description = getDescription();
if (description == null)
description = _directory.getString(getTagType()) + " (unable to formulate description)";
return "[" + _directory.getName() + "] " + getTagName() + " - " + description;
}
}