path.java

jsr170接口的java实现。是个apache的开源项目。

         *                                  format is invalid
         */
        public static PathElement fromString(String s) throws IllegalArgumentException {
            if (s == null) {
                throw new IllegalArgumentException("null PathElement literal");
            }
            if (s.equals(RootElement.LITERAL)) {
                return ROOT_ELEMENT;
            } else if (s.equals(CurrentElement.LITERAL)) {
                return CURRENT_ELEMENT;
            } else if (s.equals(ParentElement.LITERAL)) {
                return PARENT_ELEMENT;
            }

            int pos = s.indexOf('[');
            if (pos == -1) {
                QName name = QName.valueOf(s);
                return new NameElement(name, INDEX_UNDEFINED);
            }
            QName name = QName.valueOf(s.substring(0, pos));
            int pos1 = s.indexOf(']');
            if (pos1 == -1) {
                throw new IllegalArgumentException("invalid PathElement literal: " + s + " (missing ']')");
            }
            try {
                int index = Integer.valueOf(s.substring(pos + 1, pos1)).intValue();
                if (index < 1) {
                    throw new IllegalArgumentException("invalid PathElement literal: " + s + " (index is 1-based)");
                }
                return new NameElement(name, index);
            } catch (Throwable t) {
                throw new IllegalArgumentException("invalid PathElement literal: " + s + " (" + t.getMessage() + ")");
            }
        }

        /**
         * Computes a hash code for this path element.
         *
         * @return hash code
         */
        public int hashCode() {
            int h = 17;
            h = 37 * h + normalizeIndex(index);
            h = 37 * h + name.hashCode();
            return h;
        }

        /**
         * Check for path element equality. Returns true if the given
         * object is a PathElement and contains the same name and index
         * as this one.
         *
         * @param obj the object to compare with
         * @return <code>true</code> if the path elements are equal
         */
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj instanceof PathElement) {
                PathElement other = (PathElement) obj;
                return name.equals(other.name)
                        && normalizeIndex(index) == normalizeIndex(other.index);
            }
            return false;
        }

        /**
         * Normalizes index value {@link Path#INDEX_UNDEFINED} to
         * {@link Path#INDEX_DEFAULT} for {@link #equals(Object)} and
         * {@link #hashCode()}.
         * @param index
         * @return normalized index
         */
        private int normalizeIndex(int index) {
            return index == Path.INDEX_UNDEFINED ? Path.INDEX_DEFAULT : index;
        }
      
        /**
         * Returns <code>true</code> if this element denotes the <i>root</i> element,
         * otherwise returns <code>false</code>.
         *
         * @return <code>true</code> if this element denotes the <i>root</i>
         *         element; otherwise <code>false</code>
         */
        abstract public boolean denotesRoot();

        /**
         * Returns <code>true</code> if this element denotes the <i>parent</i>
         * ('..') element, otherwise returns <code>false</code>.
         *
         * @return <code>true</code> if this element denotes the <i>parent</i>
         *         element; otherwise <code>false</code>
         */
        abstract public boolean denotesParent();

        /**
         * Returns <code>true</code> if this element denotes the <i>current</i>
         * ('.') element, otherwise returns <code>false</code>.
         *
         * @return <code>true</code> if this element denotes the <i>current</i>
         *         element; otherwise <code>false</code>
         */
        abstract public boolean denotesCurrent();

        /**
         * Returns <code>true</code> if this element represents a regular name
         * (i.e. neither root, '.' nor '..'), otherwise returns <code>false</code>.
         *
         * @return <code>true</code> if this element represents a regular name;
         *         otherwise <code>false</code>
         */
        abstract public boolean denotesName();

    }

    public static final class RootElement extends PathElement {
        // use a literal that is an illegal name character to avoid collisions
        static final String LITERAL = "*";

        private RootElement() {
            super(QName.ROOT, Path.INDEX_UNDEFINED);
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesName()
         */
        public boolean denotesName() {
            return false;
        }

        /**
         * Returns true.
         *
         * @return true
         * @see Path.PathElement#denotesRoot()
         */
        public boolean denotesRoot() {
            return true;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesParent()
         */
        public boolean denotesParent() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesCurrent()
         */
        public boolean denotesCurrent() {
            return false;
        }

        /**
         * {@inheritDoc}
         * <p/>
         * Returns <code>""</code>
         * @return <code>""</code>
         */
        public String toJCRName(NamespaceResolver resolver) {
            return "";
        }

        /**
         * {@inheritDoc}
         */
        public void toJCRName(NamespaceResolver resolver, StringBuffer buf) {
            // append empty string, i.e. nothing.
        }

        /**
         * @return {@link #LITERAL}
         * @see Object#toString()
         */
        public String toString() {
            return LITERAL;
        }
    }


    public static final class CurrentElement extends PathElement {
        static final String LITERAL = ".";

        private CurrentElement() {
            super(new QName(QName.NS_DEFAULT_URI, LITERAL), Path.INDEX_UNDEFINED);
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesName()
         */
        public boolean denotesName() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesRoot()
         */
        public boolean denotesRoot() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesParent()
         */
        public boolean denotesParent() {
            return false;
        }

        /**
         * Returns true.
         *
         * @return true
         * @see Path.PathElement#denotesCurrent()
         */
        public boolean denotesCurrent() {
            return true;
        }

        /**
         * {@inheritDoc}
         * <p/>
         * Returns <code>"."</code>
         * @return <code>"."</code>
         */
        public String toJCRName(NamespaceResolver resolver) {
            return LITERAL;
        }

        /**
         * {@inheritDoc}
         */
        public void toJCRName(NamespaceResolver resolver, StringBuffer buf) {
            buf.append(LITERAL);
        }

        /**
         * @return {@link #LITERAL}
         * @see Object#toString()
         */
        public String toString() {
            return LITERAL;
        }
    }

    public static final class ParentElement extends PathElement {
        static final String LITERAL = "..";

        private ParentElement() {
            super(new QName(QName.NS_DEFAULT_URI, LITERAL), Path.INDEX_UNDEFINED);
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesName()
         */
        public boolean denotesName() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesRoot()
         */
        public boolean denotesRoot() {
            return false;
        }

        /**
         * Returns true.
         *
         * @return true
         * @see Path.PathElement#denotesParent()
         */
        public boolean denotesParent() {
            return true;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesCurrent()
         */
        public boolean denotesCurrent() {
            return false;
        }

        /**
         * {@inheritDoc}
         * <p/>
         * Returns <code>".."</code>
         * @return <code>".."</code>
         */
        public String toJCRName(NamespaceResolver resolver) {
            return LITERAL;
        }

        /**
         * {@inheritDoc}
         */
        public void toJCRName(NamespaceResolver resolver, StringBuffer buf) {
            buf.append(LITERAL);
        }

        /**
         * @return {@link #LITERAL}
         * @see Object#toString()
         */
        public String toString() {
            return LITERAL;
        }
    }

    public static final class NameElement extends PathElement {

        private NameElement(QName name, int index) {
            super(name, index);
        }

        /**
         * Returns true.
         *
         * @return true
         * @see Path.PathElement#denotesName()
         */
        public boolean denotesName() {
            return true;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesRoot()
         */
        public boolean denotesRoot() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesParent()
         */
        public boolean denotesParent() {
            return false;
        }

        /**
         * Returns false.
         *
         * @return false
         * @see Path.PathElement#denotesCurrent()
         */
        public boolean denotesCurrent() {
            return false;
        }
    }
}