/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
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package java.awt.datatransfer;
import sun.awt.datatransfer.DataTransferer;
import sun.reflect.misc.ReflectUtil;
import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.Externalizable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.OptionalDataException;
import java.io.Reader;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Objects;
import static sun.security.util.SecurityConstants.GET_CLASSLOADER_PERMISSION;
/**
* A {@code DataFlavor} provides meta information about data. {@code DataFlavor}
* is typically used to access data on the clipboard, or during
* a drag and drop operation.
* <p>
* An instance of {@code DataFlavor} encapsulates a content type as
* defined in <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
* and <a href="http://www.ietf.org/rfc/rfc2046.txt">RFC 2046</a>.
* A content type is typically referred to as a MIME type.
* <p>
* A content type consists of a media type (referred
* to as the primary type), a subtype, and optional parameters. See
* <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
* for details on the syntax of a MIME type.
* <p>
* The JRE data transfer implementation interprets the parameter "class"
* of a MIME type as <B>a representation class</b>.
* The representation class reflects the class of the object being
* transferred. In other words, the representation class is the type of
* object returned by {@link Transferable#getTransferData}.
* For example, the MIME type of {@link #imageFlavor} is
* {@code "image/x-java-image;class=java.awt.Image"},
* the primary type is {@code image}, the subtype is
* {@code x-java-image}, and the representation class is
* {@code java.awt.Image}. When {@code getTransferData} is invoked
* with a {@code DataFlavor} of {@code imageFlavor}, an instance of
* {@code java.awt.Image} is returned.
* It's important to note that {@code DataFlavor} does no error checking
* against the representation class. It is up to consumers of
* {@code DataFlavor}, such as {@code Transferable}, to honor the representation
* class.
* <br>
* Note, if you do not specify a representation class when
* creating a {@code DataFlavor}, the default
* representation class is used. See appropriate documentation for
* {@code DataFlavor}'s constructors.
* <p>
* Also, {@code DataFlavor} instances with the "text" primary
* MIME type may have a "charset" parameter. Refer to
* <a href="http://www.ietf.org/rfc/rfc2046.txt">RFC 2046</a> and
* {@link #selectBestTextFlavor} for details on "text" MIME types
* and the "charset" parameter.
* <p>
* Equality of {@code DataFlavors} is determined by the primary type,
* subtype, and representation class. Refer to {@link #equals(DataFlavor)} for
* details. When determining equality, any optional parameters are ignored.
* For example, the following produces two {@code DataFlavors} that
* are considered identical:
* <pre>
* DataFlavor flavor1 = new DataFlavor(Object.class, "X-test/test; class=<java.lang.Object>; foo=bar");
* DataFlavor flavor2 = new DataFlavor(Object.class, "X-test/test; class=<java.lang.Object>; x=y");
* // The following returns true.
* flavor1.equals(flavor2);
* </pre>
* As mentioned, {@code flavor1} and {@code flavor2} are considered identical.
* As such, asking a {@code Transferable} for either {@code DataFlavor} returns
* the same results.
* <p>
* For more information on the using data transfer with Swing see
* the <a href="https://docs.oracle.com/javase/tutorial/uiswing/dnd/index.html">
* How to Use Drag and Drop and Data Transfer</a>,
* section in <em>Java Tutorial</em>.
*
* @author Blake Sullivan
* @author Laurence P. G. Cable
* @author Jeff Dunn
*/
public class DataFlavor implements Externalizable, Cloneable {
private static final long serialVersionUID = 8367026044764648243L;
private static final Class<InputStream> ioInputStreamClass = InputStream.class;
/**
* Tries to load a class from: the bootstrap loader, the system loader,
* the context loader (if one is present) and finally the loader specified.
*
* @param className the name of the class to be loaded
* @param fallback the fallback loader
* @return the class loaded
* @exception ClassNotFoundException if class is not found
*/
protected final static Class<?> tryToLoadClass(String className,
ClassLoader fallback)
throws ClassNotFoundException
{
ReflectUtil.checkPackageAccess(className);
try {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(GET_CLASSLOADER_PERMISSION);
}
ClassLoader loader = ClassLoader.getSystemClassLoader();
try {
// bootstrap class loader and system class loader if present
return Class.forName(className, true, loader);
}
catch (ClassNotFoundException exception) {
// thread context class loader if and only if present
loader = Thread.currentThread().getContextClassLoader();
if (loader != null) {
try {
return Class.forName(className, true, loader);
}
catch (ClassNotFoundException e) {
// fallback to user's class loader
}
}
}
} catch (SecurityException exception) {
// ignore secured class loaders
}
return Class.forName(className, true, fallback);
}
/*
* private initializer
*/
static private DataFlavor createConstant(Class<?> rc, String prn) {
try {
return new DataFlavor(rc, prn);
} catch (Exception e) {
return null;
}
}
/*
* private initializer
*/
static private DataFlavor createConstant(String mt, String prn) {
try {
return new DataFlavor(mt, prn);
} catch (Exception e) {
return null;
}
}
/*
* private initializer
*/
static private DataFlavor initHtmlDataFlavor(String htmlFlavorType) {
try {
return new DataFlavor ("text/html; class=java.lang.String;document=" +
htmlFlavorType + ";charset=Unicode");
} catch (Exception e) {
return null;
}
}
/**
* The <code>DataFlavor</code> representing a Java Unicode String class,
* where:
* <pre>
* representationClass = java.lang.String
* mimeType = "application/x-java-serialized-object"
* </pre>
*/
public static final DataFlavor stringFlavor = createConstant(java.lang.String.class, "Unicode String");
/**
* The <code>DataFlavor</code> representing a Java Image class,
* where:
* <pre>
* representationClass = java.awt.Image
* mimeType = "image/x-java-image"
* </pre>
*/
public static final DataFlavor imageFlavor = createConstant("image/x-java-image; class=java.awt.Image", "Image");
/**
* The <code>DataFlavor</code> representing plain text with Unicode
* encoding, where:
* <pre>
* representationClass = InputStream
* mimeType = "text/plain; charset=unicode"
* </pre>
* This <code>DataFlavor</code> has been <b>deprecated</b> because
* (1) Its representation is an InputStream, an 8-bit based representation,
* while Unicode is a 16-bit character set; and (2) The charset "unicode"
* is not well-defined. "unicode" implies a particular platform's
* implementation of Unicode, not a cross-platform implementation.
*
* @deprecated as of 1.3. Use <code>DataFlavor.getReaderForText(Transferable)</code>
* instead of <code>Transferable.getTransferData(DataFlavor.plainTextFlavor)</code>.
*/
@Deprecated
public static final DataFlavor plainTextFlavor = createConstant("text/plain; charset=unicode; class=java.io.InputStream", "Plain Text");
/**
* A MIME Content-Type of application/x-java-serialized-object represents
* a graph of Java object(s) that have been made persistent.
*
* The representation class associated with this <code>DataFlavor</code>
* identifies the Java type of an object returned as a reference
* from an invocation <code>java.awt.datatransfer.getTransferData</code>.
*/
public static final String javaSerializedObjectMimeType = "application/x-java-serialized-object";
/**
* To transfer a list of files to/from Java (and the underlying
* platform) a <code>DataFlavor</code> of this type/subtype and
* representation class of <code>java.util.List</code> is used.
* Each element of the list is required/guaranteed to be of type
* <code>java.io.File</code>.
*/
public static final DataFlavor javaFileListFlavor = createConstant("application/x-java-file-list;class=java.util.List", null);
/**
* To transfer a reference to an arbitrary Java object reference that
* has no associated MIME Content-type, across a <code>Transferable</code>
* interface WITHIN THE SAME JVM, a <code>DataFlavor</code>
* with this type/subtype is used, with a <code>representationClass</code>
* equal to the type of the class/interface being passed across the
* <code>Transferable</code>.
* <p>
* The object reference returned from
* <code>Transferable.getTransferData</code> for a <code>DataFlavor</code>
* with this MIME Content-Type is required to be
* an instance of the representation Class of the <code>DataFlavor</code>.
*/
public static final String javaJVMLocalObjectMimeType = "application/x-java-jvm-local-objectref";
/**
* In order to pass a live link to a Remote object via a Drag and Drop
* <code>ACTION_LINK</code> operation a Mime Content Type of
* application/x-java-remote-object should be used,
* where the representation class of the <code>DataFlavor</code>
* represents the type of the <code>Remote</code> interface to be
* transferred.
*/
public static final String javaRemoteObjectMimeType = "application/x-java-remote-object";
/**
* Represents a piece of an HTML markup. The markup consists of the part
* selected on the source side. Therefore some tags in the markup may be
* unpaired. If the flavor is used to represent the data in
* a {@link Transferable} instance, no additional changes will be made.
* This DataFlavor instance represents the same HTML markup as DataFlavor
* instances which content MIME type does not contain document parameter
* and representation class is the String class.
* <pre>
* representationClass = String
* mimeType = "text/html"
* </pre>
*/
public static DataFlavor selectionHtmlFlavor = initHtmlDataFlavor("selection");
/**
* Represents a piece of an HTML markup. If possible, the markup received
* from a native system is supplemented with pair tags to be
* a well-formed HTML markup. If the flavor is used to represent the data in
* a {@link Transferable} instance, no additional changes will be made.
* <pre>
* representationClass = String
* mimeType = "text/html"
* </pre>
*/
public static DataFlavor fragmentHtmlFlavor = initHtmlDataFlavor("fragment");
/**
* Represents a piece of an HTML markup. If possible, the markup
* received from a native system is supplemented with additional
* tags to make up a well-formed HTML document. If the flavor is used to
* represent the data in a {@link Transferable} instance,
* no additional changes will be made.
* <pre>
* representationClass = String
* mimeType = "text/html"
* </pre>
*/
public static DataFlavor allHtmlFlavor = initHtmlDataFlavor("all");
/**
* Constructs a new <code>DataFlavor</code>. This constructor is
* provided only for the purpose of supporting the
* <code>Externalizable</code> interface. It is not
* intended for public (client) use.
*
* @since 1.2
*/
public DataFlavor() {
super();
}
/**
* Constructs a fully specified <code>DataFlavor</code>.
*
* @exception NullPointerException if either <code>primaryType</code>,
* <code>subType</code> or <code>representationClass</code> is null
*/
private DataFlavor(String primaryType, String subType, MimeTypeParameterList params, Class<?> representationClass, String humanPresentableName) {
super();
if (primaryType == null) {
throw new NullPointerException("primaryType");
}
if (subType == null) {
throw new NullPointerException("subType");
}
if (representationClass == null) {
throw new NullPointerException("representationClass");
}
if (params == null) params = new MimeTypeParameterList();
params.set("class", representationClass.getName());
if (humanPresentableName == null) {
humanPresentableName = params.get("humanPresentableName");
if (humanPresentableName == null)
humanPresentableName = primaryType + "/" + subType;
}
try {
mimeType = new MimeType(primaryType, subType, params);
} catch (MimeTypeParseException mtpe) {
throw new IllegalArgumentException("MimeType Parse Exception: " + mtpe.getMessage());
}
this.representationClass = representationClass;
this.humanPresentableName = humanPresentableName;
mimeType.removeParameter("humanPresentableName");
}
/**
* Constructs a <code>DataFlavor</code> that represents a Java class.
* <p>
* The returned <code>DataFlavor</code> will have the following
* characteristics:
* <pre>
* representationClass = representationClass
* mimeType = application/x-java-serialized-object
* </pre>
* @param representationClass the class used to transfer data in this flavor
* @param humanPresentableName the human-readable string used to identify
* this flavor; if this parameter is <code>null</code>
* then the value of the the MIME Content Type is used
* @exception NullPointerException if <code>representationClass</code> is null
*/
public DataFlavor(Class<?> representationClass, String humanPresentableName) {
this("application", "x-java-serialized-object", null, representationClass, humanPresentableName);
if (representationClass == null) {
throw new NullPointerException("representationClass");
}
}
/**
* Constructs a <code>DataFlavor</code> that represents a
* <code>MimeType</code>.
* <p>
* The returned <code>DataFlavor</code> will have the following
* characteristics:
* <p>
* If the <code>mimeType</code> is
* "application/x-java-serialized-object; class=<representation class>",
* the result is the same as calling
* <code>new DataFlavor(Class:forName(<representation class>)</code>.
* <p>
* Otherwise:
* <pre>
* representationClass = InputStream
* mimeType = mimeType
* </pre>
* @param mimeType the string used to identify the MIME type for this flavor;
* if the the <code>mimeType</code> does not specify a
* "class=" parameter, or if the class is not successfully
* loaded, then an <code>IllegalArgumentException</code>
* is thrown
* @param humanPresentableName the human-readable string used to identify
* this flavor; if this parameter is <code>null</code>
* then the value of the the MIME Content Type is used
* @exception IllegalArgumentException if <code>mimeType</code> is
* invalid or if the class is not successfully loaded
* @exception NullPointerException if <code>mimeType</code> is null
*/
public DataFlavor(String mimeType, String humanPresentableName) {
super();
if (mimeType == null) {
throw new NullPointerException("mimeType");
}
try {
initialize(mimeType, humanPresentableName, this.getClass().getClassLoader());
} catch (MimeTypeParseException mtpe) {
throw new IllegalArgumentException("failed to parse:" + mimeType);
} catch (ClassNotFoundException cnfe) {
throw new IllegalArgumentException("can't find specified class: " + cnfe.getMessage());
}
}
/**
* Constructs a <code>DataFlavor</code> that represents a
* <code>MimeType</code>.
* <p>
* The returned <code>DataFlavor</code> will have the following
* characteristics:
* <p>
* If the mimeType is
* "application/x-java-serialized-object; class=<representation class>",
* the result is the same as calling
* <code>new DataFlavor(Class:forName(<representation class>)</code>.
* <p>
* Otherwise:
* <pre>
* representationClass = InputStream
* mimeType = mimeType
* </pre>
* @param mimeType the string used to identify the MIME type for this flavor
* @param humanPresentableName the human-readable string used to
* identify this flavor
* @param classLoader the class loader to use
* @exception ClassNotFoundException if the class is not loaded
* @exception IllegalArgumentException if <code>mimeType</code> is
* invalid
* @exception NullPointerException if <code>mimeType</code> is null
*/
public DataFlavor(String mimeType, String humanPresentableName, ClassLoader classLoader) throws ClassNotFoundException {
super();
if (mimeType == null) {
throw new NullPointerException("mimeType");
}
try {
initialize(mimeType, humanPresentableName, classLoader);
} catch (MimeTypeParseException mtpe) {
throw new IllegalArgumentException("failed to parse:" + mimeType);
}
}
/**
* Constructs a <code>DataFlavor</code> from a <code>mimeType</code> string.
* The string can specify a "class=<fully specified Java class name>"
* parameter to create a <code>DataFlavor</code> with the desired
* representation class. If the string does not contain "class=" parameter,
* <code>java.io.InputStream</code> is used as default.
*
* @param mimeType the string used to identify the MIME type for this flavor;
* if the class specified by "class=" parameter is not
* successfully loaded, then an
* <code>ClassNotFoundException</code> is thrown
* @exception ClassNotFoundException if the class is not loaded
* @exception IllegalArgumentException if <code>mimeType</code> is
* invalid
* @exception NullPointerException if <code>mimeType</code> is null
*/
public DataFlavor(String mimeType) throws ClassNotFoundException {
super();
if (mimeType == null) {
throw new NullPointerException("mimeType");
}
try {
initialize(mimeType, null, this.getClass().getClassLoader());
} catch (MimeTypeParseException mtpe) {
throw new IllegalArgumentException("failed to parse:" + mimeType);
}
}
/**
* Common initialization code called from various constructors.
*
* @param mimeType the MIME Content Type (must have a class= param)
* @param humanPresentableName the human Presentable Name or
* <code>null</code>
* @param classLoader the fallback class loader to resolve against
*
* @throws MimeTypeParseException
* @throws ClassNotFoundException
* @throws NullPointerException if <code>mimeType</code> is null
*
* @see #tryToLoadClass
*/
private void initialize(String mimeType, String humanPresentableName, ClassLoader classLoader) throws MimeTypeParseException, ClassNotFoundException {
if (mimeType == null) {
throw new NullPointerException("mimeType");
}
this.mimeType = new MimeType(mimeType); // throws
String rcn = getParameter("class");
if (rcn == null) {
if ("application/x-java-serialized-object".equals(this.mimeType.getBaseType()))
throw new IllegalArgumentException("no representation class specified for:" + mimeType);
else
representationClass = java.io.InputStream.class; // default
} else { // got a class name
representationClass = DataFlavor.tryToLoadClass(rcn, classLoader);
}
this.mimeType.setParameter("class", representationClass.getName());
if (humanPresentableName == null) {
humanPresentableName = this.mimeType.getParameter("humanPresentableName");
if (humanPresentableName == null)
humanPresentableName = this.mimeType.getPrimaryType() + "/" + this.mimeType.getSubType();
}
this.humanPresentableName = humanPresentableName; // set it.
this.mimeType.removeParameter("humanPresentableName"); // just in case
}
/**
* String representation of this <code>DataFlavor</code> and its
* parameters. The resulting <code>String</code> contains the name of
* the <code>DataFlavor</code> class, this flavor's MIME type, and its
* representation class. If this flavor has a primary MIME type of "text",
* supports the charset parameter, and has an encoded representation, the
* flavor's charset is also included. See <code>selectBestTextFlavor</code>
* for a list of text flavors which support the charset parameter.
*
* @return string representation of this <code>DataFlavor</code>
* @see #selectBestTextFlavor
*/
public String toString() {
String string = getClass().getName();
string += "["+paramString()+"]";
return string;
}
private String paramString() {
String params = "";
params += "mimetype=";
if (mimeType == null) {
params += "null";
} else {
params += mimeType.getBaseType();
}
params += ";representationclass=";
if (representationClass == null) {
params += "null";
} else {
params += representationClass.getName();
}
if (DataTransferer.isFlavorCharsetTextType(this) &&
(isRepresentationClassInputStream() ||
isRepresentationClassByteBuffer() ||
byte[].class.equals(representationClass)))
{
params += ";charset=" + DataTransferer.getTextCharset(this);
}
return params;
}
/**
* Returns a <code>DataFlavor</code> representing plain text with Unicode
* encoding, where:
* <pre>
* representationClass = java.io.InputStream
* mimeType = "text/plain;
* charset=<platform default Unicode encoding>"
* </pre>
* Sun's implementation for Microsoft Windows uses the encoding <code>utf-16le</code>.
* Sun's implementation for Solaris and Linux uses the encoding
* <code>iso-10646-ucs-2</code>.
*
* @return a <code>DataFlavor</code> representing plain text
* with Unicode encoding
* @since 1.3
*/
public static final DataFlavor getTextPlainUnicodeFlavor() {
String encoding = null;
DataTransferer transferer = DataTransferer.getInstance();
if (transferer != null) {
encoding = transferer.getDefaultUnicodeEncoding();
}
return new DataFlavor(
"text/plain;charset="+encoding
+";class=java.io.InputStream", "Plain Text");
}
/**
* Selects the best text <code>DataFlavor</code> from an array of <code>
* DataFlavor</code>s. Only <code>DataFlavor.stringFlavor</code>, and
* equivalent flavors, and flavors that have a primary MIME type of "text",
* are considered for selection.
* <p>
* Flavors are first sorted by their MIME types in the following order:
* <ul>
* <li>"text/sgml"
* <li>"text/xml"
* <li>"text/html"
* <li>"text/rtf"
* <li>"text/enriched"
* <li>"text/richtext"
* <li>"text/uri-list"
* <li>"text/tab-separated-values"
* <li>"text/t140"
* <li>"text/rfc822-headers"
* <li>"text/parityfec"
* <li>"text/directory"
* <li>"text/css"
* <li>"text/calendar"
* <li>"application/x-java-serialized-object"
* <li>"text/plain"
* <li>"text/<other>"
* </ul>
* <p>For example, "text/sgml" will be selected over
* "text/html", and <code>DataFlavor.stringFlavor</code> will be chosen
* over <code>DataFlavor.plainTextFlavor</code>.
* <p>
* If two or more flavors share the best MIME type in the array, then that
* MIME type will be checked to see if it supports the charset parameter.
* <p>
* The following MIME types support, or are treated as though they support,
* the charset parameter:
* <ul>
* <li>"text/sgml"
* <li>"text/xml"
* <li>"text/html"
* <li>"text/enriched"
* <li>"text/richtext"
* <li>"text/uri-list"
* <li>"text/directory"
* <li>"text/css"
* <li>"text/calendar"
* <li>"application/x-java-serialized-object"
* <li>"text/plain"
* </ul>
* The following MIME types do not support, or are treated as though they
* do not support, the charset parameter:
* <ul>
* <li>"text/rtf"
* <li>"text/tab-separated-values"
* <li>"text/t140"
* <li>"text/rfc822-headers"
* <li>"text/parityfec"
* </ul>
* For "text/<other>" MIME types, the first time the JRE needs to
* determine whether the MIME type supports the charset parameter, it will
* check whether the parameter is explicitly listed in an arbitrarily
* chosen <code>DataFlavor</code> which uses that MIME type. If so, the JRE
* will assume from that point on that the MIME type supports the charset
* parameter and will not check again. If the parameter is not explicitly
* listed, the JRE will assume from that point on that the MIME type does
* not support the charset parameter and will not check again. Because
* this check is performed on an arbitrarily chosen
* <code>DataFlavor</code>, developers must ensure that all
* <code>DataFlavor</code>s with a "text/<other>" MIME type specify
* the charset parameter if it is supported by that MIME type. Developers
* should never rely on the JRE to substitute the platform's default
* charset for a "text/<other>" DataFlavor. Failure to adhere to this
* restriction will lead to undefined behavior.
* <p>
* If the best MIME type in the array does not support the charset
* parameter, the flavors which share that MIME type will then be sorted by
* their representation classes in the following order:
* <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>,
* <code>[B</code>, <all others>.
* <p>
* If two or more flavors share the best representation class, or if no
* flavor has one of the three specified representations, then one of those
* flavors will be chosen non-deterministically.
* <p>
* If the best MIME type in the array does support the charset parameter,
* the flavors which share that MIME type will then be sorted by their
* representation classes in the following order:
* <code>java.io.Reader</code>, <code>java.lang.String</code>,
* <code>java.nio.CharBuffer</code>, <code>[C</code>, <all others>.
* <p>
* If two or more flavors share the best representation class, and that
* representation is one of the four explicitly listed, then one of those
* flavors will be chosen non-deterministically. If, however, no flavor has
* one of the four specified representations, the flavors will then be
* sorted by their charsets. Unicode charsets, such as "UTF-16", "UTF-8",
* "UTF-16BE", "UTF-16LE", and their aliases, are considered best. After
* them, the platform default charset and its aliases are selected.
* "US-ASCII" and its aliases are worst. All other charsets are chosen in
* alphabetical order, but only charsets supported by this implementation
* of the Java platform will be considered.
* <p>
* If two or more flavors share the best charset, the flavors will then
* again be sorted by their representation classes in the following order:
* <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>,
* <code>[B</code>, <all others>.
* <p>
* If two or more flavors share the best representation class, or if no
* flavor has one of the three specified representations, then one of those
* flavors will be chosen non-deterministically.
*
* @param availableFlavors an array of available <code>DataFlavor</code>s
* @return the best (highest fidelity) flavor according to the rules
* specified above, or <code>null</code>,
* if <code>availableFlavors</code> is <code>null</code>,
* has zero length, or contains no text flavors
* @since 1.3
*/
public static final DataFlavor selectBestTextFlavor(
DataFlavor[] availableFlavors) {
if (availableFlavors == null || availableFlavors.length == 0) {
return null;
}
if (textFlavorComparator == null) {
textFlavorComparator = new TextFlavorComparator();
}
DataFlavor bestFlavor =
(DataFlavor)Collections.max(Arrays.asList(availableFlavors),
textFlavorComparator);
if (!bestFlavor.isFlavorTextType()) {
return null;
}
return bestFlavor;
}
private static Comparator<DataFlavor> textFlavorComparator;
static class TextFlavorComparator
extends DataTransferer.DataFlavorComparator {
/**
* Compares two <code>DataFlavor</code> objects. Returns a negative
* integer, zero, or a positive integer as the first
* <code>DataFlavor</code> is worse than, equal to, or better than the
* second.
* <p>
* <code>DataFlavor</code>s are ordered according to the rules outlined
* for <code>selectBestTextFlavor</code>.
*
* @param obj1 the first <code>DataFlavor</code> to be compared
* @param obj2 the second <code>DataFlavor</code> to be compared
* @return a negative integer, zero, or a positive integer as the first
* argument is worse, equal to, or better than the second
* @throws ClassCastException if either of the arguments is not an
* instance of <code>DataFlavor</code>
* @throws NullPointerException if either of the arguments is
* <code>null</code>
*
* @see #selectBestTextFlavor
*/
public int compare(Object obj1, Object obj2) {
DataFlavor flavor1 = (DataFlavor)obj1;
DataFlavor flavor2 = (DataFlavor)obj2;
if (flavor1.isFlavorTextType()) {
if (flavor2.isFlavorTextType()) {
return super.compare(obj1, obj2);
} else {
return 1;
}
} else if (flavor2.isFlavorTextType()) {
return -1;
} else {
return 0;
}
}
}
/**
* Gets a Reader for a text flavor, decoded, if necessary, for the expected
* charset (encoding). The supported representation classes are
* <code>java.io.Reader</code>, <code>java.lang.String</code>,
* <code>java.nio.CharBuffer</code>, <code>[C</code>,
* <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>,
* and <code>[B</code>.
* <p>
* Because text flavors which do not support the charset parameter are
* encoded in a non-standard format, this method should not be called for
* such flavors. However, in order to maintain backward-compatibility,
* if this method is called for such a flavor, this method will treat the
* flavor as though it supports the charset parameter and attempt to
* decode it accordingly. See <code>selectBestTextFlavor</code> for a list
* of text flavors which do not support the charset parameter.
*
* @param transferable the <code>Transferable</code> whose data will be
* requested in this flavor
*
* @return a <code>Reader</code> to read the <code>Transferable</code>'s
* data
*
* @exception IllegalArgumentException if the representation class
* is not one of the seven listed above
* @exception IllegalArgumentException if the <code>Transferable</code>
* has <code>null</code> data
* @exception NullPointerException if the <code>Transferable</code> is
* <code>null</code>
* @exception UnsupportedEncodingException if this flavor's representation
* is <code>java.io.InputStream</code>,
* <code>java.nio.ByteBuffer</code>, or <code>[B</code> and
* this flavor's encoding is not supported by this
* implementation of the Java platform
* @exception UnsupportedFlavorException if the <code>Transferable</code>
* does not support this flavor
* @exception IOException if the data cannot be read because of an
* I/O error
* @see #selectBestTextFlavor
* @since 1.3
*/
public Reader getReaderForText(Transferable transferable)
throws UnsupportedFlavorException, IOException
{
Object transferObject = transferable.getTransferData(this);
if (transferObject == null) {
throw new IllegalArgumentException
("getTransferData() returned null");
}
if (transferObject instanceof Reader) {
return (Reader)transferObject;
} else if (transferObject instanceof String) {
return new StringReader((String)transferObject);
} else if (transferObject instanceof CharBuffer) {
CharBuffer buffer = (CharBuffer)transferObject;
int size = buffer.remaining();
char[] chars = new char[size];
buffer.get(chars, 0, size);
return new CharArrayReader(chars);
} else if (transferObject instanceof char[]) {
return new CharArrayReader((char[])transferObject);
}
InputStream stream = null;
if (transferObject instanceof InputStream) {
stream = (InputStream)transferObject;
} else if (transferObject instanceof ByteBuffer) {
ByteBuffer buffer = (ByteBuffer)transferObject;
int size = buffer.remaining();
byte[] bytes = new byte[size];
buffer.get(bytes, 0, size);
stream = new ByteArrayInputStream(bytes);
} else if (transferObject instanceof byte[]) {
stream = new ByteArrayInputStream((byte[])transferObject);
}
if (stream == null) {
throw new IllegalArgumentException("transfer data is not Reader, String, CharBuffer, char array, InputStream, ByteBuffer, or byte array");
}
String encoding = getParameter("charset");
return (encoding == null)
? new InputStreamReader(stream)
: new InputStreamReader(stream, encoding);
}
/**
* Returns the MIME type string for this <code>DataFlavor</code>.
* @return the MIME type string for this flavor
*/
public String getMimeType() {
return (mimeType != null) ? mimeType.toString() : null;
}
/**
* Returns the <code>Class</code> which objects supporting this
* <code>DataFlavor</code> will return when this <code>DataFlavor</code>
* is requested.
* @return the <code>Class</code> which objects supporting this
* <code>DataFlavor</code> will return when this <code>DataFlavor</code>
* is requested
*/
public Class<?> getRepresentationClass() {
return representationClass;
}
/**
* Returns the human presentable name for the data format that this
* <code>DataFlavor</code> represents. This name would be localized
* for different countries.
* @return the human presentable name for the data format that this
* <code>DataFlavor</code> represents
*/
public String getHumanPresentableName() {
return humanPresentableName;
}
/**
* Returns the primary MIME type for this <code>DataFlavor</code>.
* @return the primary MIME type of this <code>DataFlavor</code>
*/
public String getPrimaryType() {
return (mimeType != null) ? mimeType.getPrimaryType() : null;
}
/**
* Returns the sub MIME type of this <code>DataFlavor</code>.
* @return the Sub MIME type of this <code>DataFlavor</code>
*/
public String getSubType() {
return (mimeType != null) ? mimeType.getSubType() : null;
}
/**
* Returns the human presentable name for this <code>DataFlavor</code>
* if <code>paramName</code> equals "humanPresentableName". Otherwise
* returns the MIME type value associated with <code>paramName</code>.
*
* @param paramName the parameter name requested
* @return the value of the name parameter, or <code>null</code>
* if there is no associated value
*/
public String getParameter(String paramName) {
if (paramName.equals("humanPresentableName")) {
return humanPresentableName;
} else {
return (mimeType != null)
? mimeType.getParameter(paramName) : null;
}
}
/**
* Sets the human presentable name for the data format that this
* <code>DataFlavor</code> represents. This name would be localized
* for different countries.
* @param humanPresentableName the new human presentable name
*/
public void setHumanPresentableName(String humanPresentableName) {
this.humanPresentableName = humanPresentableName;
}
/**
* {@inheritDoc}
* <p>
* The equals comparison for the {@code DataFlavor} class is implemented
* as follows: Two <code>DataFlavor</code>s are considered equal if and
* only if their MIME primary type and subtype and representation class are
* equal. Additionally, if the primary type is "text", the subtype denotes
* a text flavor which supports the charset parameter, and the
* representation class is not <code>java.io.Reader</code>,
* <code>java.lang.String</code>, <code>java.nio.CharBuffer</code>, or
* <code>[C</code>, the <code>charset</code> parameter must also be equal.
* If a charset is not explicitly specified for one or both
* <code>DataFlavor</code>s, the platform default encoding is assumed. See
* <code>selectBestTextFlavor</code> for a list of text flavors which
* support the charset parameter.
*
* @param o the <code>Object</code> to compare with <code>this</code>
* @return <code>true</code> if <code>that</code> is equivalent to this
* <code>DataFlavor</code>; <code>false</code> otherwise
* @see #selectBestTextFlavor
*/
public boolean equals(Object o) {
return ((o instanceof DataFlavor) && equals((DataFlavor)o));
}
/**
* This method has the same behavior as {@link #equals(Object)}.
* The only difference being that it takes a {@code DataFlavor} instance
* as a parameter.
*
* @param that the <code>DataFlavor</code> to compare with
* <code>this</code>
* @return <code>true</code> if <code>that</code> is equivalent to this
* <code>DataFlavor</code>; <code>false</code> otherwise
* @see #selectBestTextFlavor
*/
public boolean equals(DataFlavor that) {
if (that == null) {
return false;
}
if (this == that) {
return true;
}
if (!Objects.equals(this.getRepresentationClass(), that.getRepresentationClass())) {
return false;
}
if (mimeType == null) {
if (that.mimeType != null) {
return false;
}
} else {
if (!mimeType.match(that.mimeType)) {
return false;
}
if ("text".equals(getPrimaryType())) {
if (DataTransferer.doesSubtypeSupportCharset(this)
&& representationClass != null
&& !isStandardTextRepresentationClass()) {
String thisCharset =
DataTransferer.canonicalName(this.getParameter("charset"));
String thatCharset =
DataTransferer.canonicalName(that.getParameter("charset"));
if (!Objects.equals(thisCharset, thatCharset)) {
return false;
}
}
if ("html".equals(getSubType())) {
String thisDocument = this.getParameter("document");
String thatDocument = that.getParameter("document");
if (!Objects.equals(thisDocument, thatDocument)) {
return false;
}
}
}
}
return true;
}
/**
* Compares only the <code>mimeType</code> against the passed in
* <code>String</code> and <code>representationClass</code> is
* not considered in the comparison.
*
* If <code>representationClass</code> needs to be compared, then
* <code>equals(new DataFlavor(s))</code> may be used.
* @deprecated As inconsistent with <code>hashCode()</code> contract,
* use <code>isMimeTypeEqual(String)</code> instead.
* @param s the {@code mimeType} to compare.
* @return true if the String (MimeType) is equal; false otherwise or if
* {@code s} is {@code null}
*/
@Deprecated
public boolean equals(String s) {
if (s == null || mimeType == null)
return false;
return isMimeTypeEqual(s);
}
/**
* Returns hash code for this <code>DataFlavor</code>.
* For two equal <code>DataFlavor</code>s, hash codes are equal.
* For the <code>String</code>
* that matches <code>DataFlavor.equals(String)</code>, it is not
* guaranteed that <code>DataFlavor</code>'s hash code is equal
* to the hash code of the <code>String</code>.
*
* @return a hash code for this <code>DataFlavor</code>
*/
public int hashCode() {
int total = 0;
if (representationClass != null) {
total += representationClass.hashCode();
}
if (mimeType != null) {
String primaryType = mimeType.getPrimaryType();
if (primaryType != null) {
total += primaryType.hashCode();
}
// Do not add subType.hashCode() to the total. equals uses
// MimeType.match which reports a match if one or both of the
// subTypes is '*', regardless of the other subType.
if ("text".equals(primaryType)) {
if (DataTransferer.doesSubtypeSupportCharset(this)
&& representationClass != null
&& !isStandardTextRepresentationClass()) {
String charset = DataTransferer.canonicalName(getParameter("charset"));
if (charset != null) {
total += charset.hashCode();
}
}
if ("html".equals(getSubType())) {
String document = this.getParameter("document");
if (document != null) {
total += document.hashCode();
}
}
}
}
return total;
}
/**
* Identical to {@link #equals(DataFlavor)}.
*
* @param that the <code>DataFlavor</code> to compare with
* <code>this</code>
* @return <code>true</code> if <code>that</code> is equivalent to this
* <code>DataFlavor</code>; <code>false</code> otherwise
* @see #selectBestTextFlavor
* @since 1.3
*/
public boolean match(DataFlavor that) {
return equals(that);
}
/**
* Returns whether the string representation of the MIME type passed in
* is equivalent to the MIME type of this <code>DataFlavor</code>.
* Parameters are not included in the comparison.
*
* @param mimeType the string representation of the MIME type
* @return true if the string representation of the MIME type passed in is
* equivalent to the MIME type of this <code>DataFlavor</code>;
* false otherwise
* @throws NullPointerException if mimeType is <code>null</code>
*/
public boolean isMimeTypeEqual(String mimeType) {
// JCK Test DataFlavor0117: if 'mimeType' is null, throw NPE
if (mimeType == null) {
throw new NullPointerException("mimeType");
}
if (this.mimeType == null) {
return false;
}
try {
return this.mimeType.match(new MimeType(mimeType));
} catch (MimeTypeParseException mtpe) {
return false;
}
}
/**
* Compares the <code>mimeType</code> of two <code>DataFlavor</code>
* objects. No parameters are considered.
*
* @param dataFlavor the <code>DataFlavor</code> to be compared
* @return true if the <code>MimeType</code>s are equal,
* otherwise false
*/
public final boolean isMimeTypeEqual(DataFlavor dataFlavor) {
return isMimeTypeEqual(dataFlavor.mimeType);
}
/**
* Compares the <code>mimeType</code> of two <code>DataFlavor</code>
* objects. No parameters are considered.
*
* @return true if the <code>MimeType</code>s are equal,
* otherwise false
*/
private boolean isMimeTypeEqual(MimeType mtype) {
if (this.mimeType == null) {
return (mtype == null);
}
return mimeType.match(mtype);
}
/**
* Checks if the representation class is one of the standard text
* representation classes.
*
* @return true if the representation class is one of the standard text
* representation classes, otherwise false
*/
private boolean isStandardTextRepresentationClass() {
return isRepresentationClassReader()
|| String.class.equals(representationClass)
|| isRepresentationClassCharBuffer()
|| char[].class.equals(representationClass);
}
/**
* Does the <code>DataFlavor</code> represent a serialized object?
*/
public boolean isMimeTypeSerializedObject() {
return isMimeTypeEqual(javaSerializedObjectMimeType);
}
public final Class<?> getDefaultRepresentationClass() {
return ioInputStreamClass;
}
public final String getDefaultRepresentationClassAsString() {
return getDefaultRepresentationClass().getName();
}
/**
* Does the <code>DataFlavor</code> represent a
* <code>java.io.InputStream</code>?
*/
public boolean isRepresentationClassInputStream() {
return ioInputStreamClass.isAssignableFrom(representationClass);
}
/**
* Returns whether the representation class for this
* <code>DataFlavor</code> is <code>java.io.Reader</code> or a subclass
* thereof.
*
* @since 1.4
*/
public boolean isRepresentationClassReader() {
return java.io.Reader.class.isAssignableFrom(representationClass);
}
/**
* Returns whether the representation class for this
* <code>DataFlavor</code> is <code>java.nio.CharBuffer</code> or a
* subclass thereof.
*
* @since 1.4
*/
public boolean isRepresentationClassCharBuffer() {
return java.nio.CharBuffer.class.isAssignableFrom(representationClass);
}
/**
* Returns whether the representation class for this
* <code>DataFlavor</code> is <code>java.nio.ByteBuffer</code> or a
* subclass thereof.
*
* @since 1.4
*/
public boolean isRepresentationClassByteBuffer() {
return java.nio.ByteBuffer.class.isAssignableFrom(representationClass);
}
/**
* Returns true if the representation class can be serialized.
* @return true if the representation class can be serialized
*/
public boolean isRepresentationClassSerializable() {
return java.io.Serializable.class.isAssignableFrom(representationClass);
}
/**
* Returns true if the representation class is <code>Remote</code>.
* @return true if the representation class is <code>Remote</code>
*/
public boolean isRepresentationClassRemote() {
return DataTransferer.isRemote(representationClass);
}
/**
* Returns true if the <code>DataFlavor</code> specified represents
* a serialized object.
* @return true if the <code>DataFlavor</code> specified represents
* a Serialized Object
*/
public boolean isFlavorSerializedObjectType() {
return isRepresentationClassSerializable() && isMimeTypeEqual(javaSerializedObjectMimeType);
}
/**
* Returns true if the <code>DataFlavor</code> specified represents
* a remote object.
* @return true if the <code>DataFlavor</code> specified represents
* a Remote Object
*/
public boolean isFlavorRemoteObjectType() {
return isRepresentationClassRemote()
&& isRepresentationClassSerializable()
&& isMimeTypeEqual(javaRemoteObjectMimeType);
}
/**
* Returns true if the <code>DataFlavor</code> specified represents
* a list of file objects.
* @return true if the <code>DataFlavor</code> specified represents
* a List of File objects
*/
public boolean isFlavorJavaFileListType() {
if (mimeType == null || representationClass == null)
return false;
return java.util.List.class.isAssignableFrom(representationClass) &&
mimeType.match(javaFileListFlavor.mimeType);
}
/**
* Returns whether this <code>DataFlavor</code> is a valid text flavor for
* this implementation of the Java platform. Only flavors equivalent to
* <code>DataFlavor.stringFlavor</code> and <code>DataFlavor</code>s with
* a primary MIME type of "text" can be valid text flavors.
* <p>
* If this flavor supports the charset parameter, it must be equivalent to
* <code>DataFlavor.stringFlavor</code>, or its representation must be
* <code>java.io.Reader</code>, <code>java.lang.String</code>,
* <code>java.nio.CharBuffer</code>, <code>[C</code>,
* <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>, or
* <code>[B</code>. If the representation is
* <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>, or
* <code>[B</code>, then this flavor's <code>charset</code> parameter must
* be supported by this implementation of the Java platform. If a charset
* is not specified, then the platform default charset, which is always
* supported, is assumed.
* <p>
* If this flavor does not support the charset parameter, its
* representation must be <code>java.io.InputStream</code>,
* <code>java.nio.ByteBuffer</code>, or <code>[B</code>.
* <p>
* See <code>selectBestTextFlavor</code> for a list of text flavors which
* support the charset parameter.
*
* @return <code>true</code> if this <code>DataFlavor</code> is a valid
* text flavor as described above; <code>false</code> otherwise
* @see #selectBestTextFlavor
* @since 1.4
*/
public boolean isFlavorTextType() {
return (DataTransferer.isFlavorCharsetTextType(this) ||
DataTransferer.isFlavorNoncharsetTextType(this));
}
/**
* Serializes this <code>DataFlavor</code>.
*/
public synchronized void writeExternal(ObjectOutput os) throws IOException {
if (mimeType != null) {
mimeType.setParameter("humanPresentableName", humanPresentableName);
os.writeObject(mimeType);
mimeType.removeParameter("humanPresentableName");
} else {
os.writeObject(null);
}
os.writeObject(representationClass);
}
/**
* Restores this <code>DataFlavor</code> from a Serialized state.
*/
public synchronized void readExternal(ObjectInput is) throws IOException , ClassNotFoundException {
String rcn = null;
mimeType = (MimeType)is.readObject();
if (mimeType != null) {
humanPresentableName =
mimeType.getParameter("humanPresentableName");
mimeType.removeParameter("humanPresentableName");
rcn = mimeType.getParameter("class");
if (rcn == null) {
throw new IOException("no class parameter specified in: " +
mimeType);
}
}
try {
representationClass = (Class)is.readObject();
} catch (OptionalDataException ode) {
if (!ode.eof || ode.length != 0) {
throw ode;
}
// Ensure backward compatibility.
// Old versions didn't write the representation class to the stream.
if (rcn != null) {
representationClass =
DataFlavor.tryToLoadClass(rcn, getClass().getClassLoader());
}
}
}
/**
* Returns a clone of this <code>DataFlavor</code>.
* @return a clone of this <code>DataFlavor</code>
*/
public Object clone() throws CloneNotSupportedException {
Object newObj = super.clone();
if (mimeType != null) {
((DataFlavor)newObj).mimeType = (MimeType)mimeType.clone();
}
return newObj;
} // clone()
/**
* Called on <code>DataFlavor</code> for every MIME Type parameter
* to allow <code>DataFlavor</code> subclasses to handle special
* parameters like the text/plain <code>charset</code>
* parameters, whose values are case insensitive. (MIME type parameter
* values are supposed to be case sensitive.
* <p>
* This method is called for each parameter name/value pair and should
* return the normalized representation of the <code>parameterValue</code>.
*
* This method is never invoked by this implementation from 1.1 onwards.
*
* @deprecated
*/
@Deprecated
protected String normalizeMimeTypeParameter(String parameterName, String parameterValue) {
return parameterValue;
}
/**
* Called for each MIME type string to give <code>DataFlavor</code> subtypes
* the opportunity to change how the normalization of MIME types is
* accomplished. One possible use would be to add default
* parameter/value pairs in cases where none are present in the MIME
* type string passed in.
*
* This method is never invoked by this implementation from 1.1 onwards.
*
* @deprecated
*/
@Deprecated
protected String normalizeMimeType(String mimeType) {
return mimeType;
}
/*
* fields
*/
/* placeholder for caching any platform-specific data for flavor */
transient int atom;
/* Mime Type of DataFlavor */
MimeType mimeType;
private String humanPresentableName;
/** Java class of objects this DataFlavor represents **/
private Class<?> representationClass;
} // class DataFlavor
