Java example source code file (Datatype.java)

This example Java source code file (Datatype.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

datatypeexception, datatypestreamingvalidator, id_type_idrefs, id_type_null, object, string, validationcontext

The Datatype.java Java example source code

/**
 * Copyright (c) 2001, Thai Open Source Software Center Ltd
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *     Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 *     Neither the name of the Thai Open Source Software Center Ltd nor
 *     the names of its contributors may be used to endorse or promote
 *     products derived from this software without specific prior written
 *     permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.relaxng.datatype;

/**
 * Datatype object.
 *
 * This object has the following functionality:
 *
 * <ol>
 *  <li> functionality to identify a class of character sequences. This is
 *       done through the isValid method.
 *
 *  <li> functionality to produce a "value object" from a character sequence and
 *               context information.
 *
 *  <li> functionality to test the equality of two value objects.
 * </ol>
 *
 * This interface also defines the createStreamingValidator method,
 * which is intended to efficiently support the validation of
 * large character sequences.
 *
 * @author <a href="mailto:jjc@jclark.com">James Clark
 * @author <a href="mailto:kohsuke.kawaguchi@sun.com">Kohsuke KAWAGUCHI
 */
public interface Datatype {

        /**
         * Checks if the specified 'literal' matches this Datatype
         * with respect to the current context.
         *
         * @param literal
         *              the lexical representation to be checked.
         * @param context
         *              If this datatype is context-dependent
         *              (i.e. the {@link #isContextDependent} method returns true),
         *              then the caller must provide a non-null valid context object.
         *              Otherwise, the caller can pass null.
         *
         * @return
         *              true if the 'literal' is a member of this Datatype;
         *              false if it's not a member of this Datatype.
         */
        boolean isValid( String literal, ValidationContext context );

        /**
         * Similar to the isValid method but throws an exception with diagnosis
         * in case of errors.
         *
         * <p>
         * If the specified 'literal' is a valid lexical representation for this
         * datatype, then this method must return without throwing any exception.
         * If not, the callee must throw an exception (with diagnosis message,
         * if possible.)
         *
         * <p>
         * The application can use this method to provide detailed error message
         * to users. This method is kept separate from the isValid method to
         * achieve higher performance during normal validation.
         *
         * @exception DatatypeException
         *              If the given literal is invalid, then this exception is thrown.
         *              If the callee supports error diagnosis, then the exception should
         *              contain a diagnosis message.
         */
        void checkValid( String literal, ValidationContext context )
                throws DatatypeException;

        /**
         * Creates an instance of a streaming validator for this type.
         *
         * <p>
         * By using streaming validators instead of the isValid method,
         * the caller can avoid keeping the entire string, which is
         * sometimes quite big, in memory.
         *
         * @param context
         *              If this datatype is context-dependent
         *              (i.e. the {@link #isContextDependent} method returns true),
         *              then the caller must provide a non-null valid context object.
         *              Otherwise, the caller can pass null.
         *              The callee may keep a reference to this context object
         *              only while the returned streaming validator is being used.
         */
        DatatypeStreamingValidator createStreamingValidator( ValidationContext context );

        /**
         * Converts lexcial value and the current context to the corresponding
         * value object.
         *
         * <p>
         * The caller cannot generally assume that the value object is
         * a meaningful Java object. For example, the caller cannot expect
         * this method to return <code>java.lang.Number type for
         * the "integer" type of XML Schema Part 2.
         *
         * <p>
         * Also, the caller cannot assume that the equals method and
         * the hashCode method of the value object are consistent with
         * the semantics of the datatype. For that purpose, the sameValue
         * method and the valueHashCode method have to be used. Note that
         * this means you cannot use classes like
         * <code>java.util.Hashtable to store the value objects.
         *
         * <p>
         * The returned value object should be used solely for the sameValue
         * and valueHashCode methods.
         *
         * @param context
         *              If this datatype is context-dependent
         *              (when the {@link #isContextDependent} method returns true),
         *              then the caller must provide a non-null valid context object.
         *              Otherwise, the caller can pass null.
         *
         * @return      null
         *              when the given lexical value is not a valid lexical
         *              value for this type.
         */
        Object createValue( String literal, ValidationContext context );

        /**
         * Tests the equality of two value objects which were originally
         * created by the createValue method of this object.
         *
         * The behavior is undefined if objects not created by this type
         * are passed. It is the caller's responsibility to ensure that
         * value objects belong to this type.
         *
         * @return
         *              true if two value objects are considered equal according to
         *              the definition of this datatype; false if otherwise.
         */
        boolean sameValue( Object value1, Object value2 );


        /**
         * Computes the hash code for a value object,
         * which is consistent with the sameValue method.
         *
         * @return
         *              hash code for the specified value object.
         */
        int valueHashCode( Object value );




        /**
         * Indicates that the datatype doesn't have ID/IDREF semantics.
         *
         * This value is one of the possible return values of the
         * {@link #getIdType} method.
         */
        public static final int ID_TYPE_NULL = 0;

        /**
         * Indicates that RELAX NG compatibility processors should
         * treat this datatype as having ID semantics.
         *
         * This value is one of the possible return values of the
         * {@link #getIdType} method.
         */
        public static final int ID_TYPE_ID = 1;

        /**
         * Indicates that RELAX NG compatibility processors should
         * treat this datatype as having IDREF semantics.
         *
         * This value is one of the possible return values of the
         * {@link #getIdType} method.
         */
        public static final int ID_TYPE_IDREF = 2;

        /**
         * Indicates that RELAX NG compatibility processors should
         * treat this datatype as having IDREFS semantics.
         *
         * This value is one of the possible return values of the
         * {@link #getIdType} method.
         */
        public static final int ID_TYPE_IDREFS = 3;

        /**
         * Checks if the ID/IDREF semantics is associated with this
         * datatype.
         *
         * <p>
         * This method is introduced to support the RELAX NG DTD
         * compatibility spec. (Of course it's always free to use
         * this method for other purposes.)
         *
         * <p>
         * If you are implementing a datatype library and have no idea about
         * the "RELAX NG DTD compatibility" thing, just return
         * <code>ID_TYPE_NULL is fine.
         *
         * @return
         *              If this datatype doesn't have any ID/IDREF semantics,
         *              it returns {@link #ID_TYPE_NULL}. If it has such a semantics
         *              (for example, XSD:ID, XSD:IDREF and comp:ID type), then
         *              it returns {@link #ID_TYPE_ID}, {@link #ID_TYPE_IDREF} or
         *              {@link #ID_TYPE_IDREFS}.
         */
        public int getIdType();


        /**
         * Checks if this datatype may need a context object for
         * the validation.
         *
         * <p>
         * The callee must return true even when the context
         * is not always necessary. (For example, the "QName" type
         * doesn't need a context object when validating unprefixed
         * string. But nonetheless QName must return true.)
         *
         * <p>
         * XSD's <code>string and short types
         * are examples of context-independent datatypes.
         * Its <code>QName and ENTITY types
         * are examples of context-dependent datatypes.
         *
         * <p>
         * When a datatype is context-independent, then
         * the {@link #isValid} method, the {@link #checkValid} method,
         * the {@link #createStreamingValidator} method and
         * the {@link #createValue} method can be called without
         * providing a context object.
         *
         * @return
         *              <b>true if this datatype is context-dependent
         *              (it needs a context object sometimes);
         *
         *              <b>false if this datatype is context-independent
         *              (it never needs a context object).
         */
        public boolean isContextDependent();
}