ActivationDataFlavor.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package javax.activation;

import java.awt.datatransfer.DataFlavor;
import java.io.IOException;
import javax.activation.MimeType;

/**
 * The ActivationDataFlavor class is a special subclass of
 * <code>java.awt.datatransfer.DataFlavor</code>. It allows the JAF to
 * set all three values stored by the DataFlavor class via a new
 * constructor. It also contains improved MIME parsing in the <code>equals
 * </code> method. Except for the improved parsing, its semantics are
 * identical to that of the JDK's DataFlavor class.
 *
 * @since 1.6
 */

public class ActivationDataFlavor extends DataFlavor {

    /*
     * Raison d'etre:
     *
     * The DataFlavor class included in JDK 1.1 has several limitations
     * including piss poor MIME type parsing, and the limitation of
     * only supporting serialized objects and InputStreams as
     * representation objects. This class 'fixes' that.
     */

    // I think for now I'll keep copies of all the variables and
    // then later I may choose try to better coexist with the base
    // class *sigh*
    private String mimeType = null;
    private MimeType mimeObject = null;
    private String humanPresentableName = null;
    private Class representationClass = null;

    /**
     * Construct a DataFlavor that represents an arbitrary
     * Java object. This constructor is an extension of the
     * JDK's DataFlavor in that it allows the explicit setting
     * of all three DataFlavor attributes.
     * <p>
     * The returned DataFlavor will have the following characteristics:
     * <p>
     * representationClass = representationClass<br>
     * mimeType            = mimeType<br>
     * humanName           = humanName
     * <p>
     *
     * @param representationClass the class used in this DataFlavor
     * @param mimeType the MIME type of the data represented by this class
     * @param humanPresentableName the human presentable name of the flavor
     */
    public ActivationDataFlavor(Class representationClass,
                      String mimeType, String humanPresentableName) {
        super(mimeType, humanPresentableName); // need to call super

        // init private variables:
        this.mimeType = mimeType;
        this.humanPresentableName = humanPresentableName;
        this.representationClass = representationClass;
    }

    /**
     * Construct a DataFlavor that represents a MimeType.
     * <p>
     * The returned DataFlavor will have the following characteristics:
     * <p>
     * If the mimeType is "application/x-java-serialized-object;
     * class=", the result is the same as calling new
     * DataFlavor(Class.forName()) as above.
     * <p>
     * otherwise:
     * <p>
     * representationClass = InputStream<p>
     * mimeType = mimeType<p>
     *
     * @param representationClass the class used in this DataFlavor
     * @param humanPresentableName the human presentable name of the flavor
     */
    public ActivationDataFlavor(Class representationClass,
                                String humanPresentableName) {
        super(representationClass, humanPresentableName);
        this.mimeType = super.getMimeType();
        this.representationClass = representationClass;
        this.humanPresentableName = humanPresentableName;
    }

    /**
     * Construct a DataFlavor that represents a MimeType.
     * <p>
     * The returned DataFlavor will have the following characteristics:
     * <p>
     * If the mimeType is "application/x-java-serialized-object; class=",
     * the result is the same as calling new DataFlavor(Class.forName()) as
     * above, otherwise:
     * <p>
     * representationClass = InputStream<p>
     * mimeType = mimeType
     *
     * @param mimeType the MIME type of the data represented by this class
     * @param humanPresentableName the human presentable name of the flavor
     */
    public ActivationDataFlavor(String mimeType, String humanPresentableName) {
        super(mimeType, humanPresentableName);
        this.mimeType = mimeType;
        try {
            this.representationClass = Class.forName("java.io.InputStream");
        } catch (ClassNotFoundException ex) {
            // XXX - should never happen, ignore it
        }
        this.humanPresentableName = humanPresentableName;
    }

    /**
     * Return the MIME type for this DataFlavor.
     *
     * @return  the MIME type
     */
    public String getMimeType() {
        return mimeType;
    }

    /**
     * Return the representation class.
     *
     * @return  the representation class
     */
    public Class getRepresentationClass() {
        return representationClass;
    }

    /**
     * Return the Human Presentable name.
     *
     * @return  the human presentable name
     */
    public String getHumanPresentableName() {
        return humanPresentableName;
    }

    /**
     * Set the human presentable name.
     *
     * @param humanPresentableName      the name to set
     */
    public void setHumanPresentableName(String humanPresentableName) {
        this.humanPresentableName = humanPresentableName;
    }

    /**
     * Compares the DataFlavor passed in with this DataFlavor; calls
     * the <code>isMimeTypeEqual</code> method.
     *
     * @param dataFlavor        the DataFlavor to compare with
     * @return                  true if the MIME type and representation class
     *                          are the same
     */
    public boolean equals(DataFlavor dataFlavor) {
        return (isMimeTypeEqual(dataFlavor) &&
                dataFlavor.getRepresentationClass() == representationClass);
    }

    /**
     * Is the string representation of the MIME type passed in equivalent
     * to the MIME type of this DataFlavor. <p>
     *
     * ActivationDataFlavor delegates the comparison of MIME types to
     * the MimeType class included as part of the JavaBeans Activation
     * Framework. This provides a more robust comparison than is normally
     * available in the DataFlavor class.
     *
     * @param mimeType  the MIME type
     * @return          true if the same MIME type
     */
    public boolean isMimeTypeEqual(String mimeType) {
        MimeType mt = null;
        try {
            if (mimeObject == null)
                mimeObject = new MimeType(this.mimeType);
            mt = new MimeType(mimeType);
        } catch (MimeTypeParseException e) {
            // something didn't parse, do a crude comparison
            return this.mimeType.equalsIgnoreCase(mimeType);
        }

        return mimeObject.match(mt);
    }

    /**
     * Called on DataFlavor for every MIME Type parameter to allow DataFlavor
     * subclasses to handle special parameters like the text/plain charset
     * 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 parameterValue.
     * This method is never invoked by this implementation.
     *
     * @param parameterName     the parameter name
     * @param parameterValue    the parameter value
     * @return                  the normalized parameter value
     * @deprecated
     */
    protected String normalizeMimeTypeParameter(String parameterName,
                                                String parameterValue) {
        return parameterValue;
    }

    /**
     * Called for each MIME type string to give DataFlavor 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.
     *
     * @param mimeType  the MIME type
     * @return          the normalized MIME type
     * @deprecated
     */
    protected String normalizeMimeType(String mimeType) {
        return mimeType;
    }
}