AcceptCharset.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.    
 */

package org.apache.wink.common.internal.http;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.ws.rs.ext.RuntimeDelegate;
import javax.ws.rs.ext.RuntimeDelegate.HeaderDelegate;

/**
 * Represent HTTP Accept-Charset header.
 * <p>
 * This version of the API does not support construction.
 * 
 * @see <a href='http://tools.ietf.org/html/rfc2616#section-14.4'>RFC 2616
 *      14.4</a>
 */
public class AcceptCharset {

    public static final class ValuedCharset implements Comparable<ValuedCharset> {
        public final double qValue;
        public final String charset;

        public ValuedCharset(double qValue, String charset) {
            this.qValue = qValue;
            this.charset = charset;
        }

        public int compareTo(ValuedCharset other) {
            return Double.compare(qValue, other.qValue);
        }

        public boolean isWildcard() {
            return charset == null;
        }

        @Override
        public boolean equals(Object obj) {
            if (!(obj instanceof ValuedCharset)) {
                return false;
            }

            ValuedCharset other = (ValuedCharset)obj;
            if (other.qValue != this.qValue) {
                return false;
            }

            if (charset == null) {
                if (other.charset != null) {
                    return false;
                }
            } else {
                if (!charset.equals(other.charset)) {
                    return false;
                }
            }

            return true;
        }

        @Override
        public int hashCode() {
            int result = 17;
            result = 31 * result + Double.valueOf(qValue).hashCode();
            result = 31 * result + charset.hashCode();
            return result;
        }

        @Override
        public String toString() {
            return charset + ";q=" + qValue; //$NON-NLS-1$
        }
    }

    private static final HeaderDelegate<AcceptCharset> delegate =
                                                                    RuntimeDelegate
                                                                        .getInstance()
                                                                        .createHeaderDelegate(AcceptCharset.class);

    private final String                               acceptCharsetHeader;
    private final boolean                              anyAllowed;
    private final List<String>                         acceptable;
    private final List<String>                         banned;
    private final List<AcceptCharset.ValuedCharset>    valuedCharsets;

    public AcceptCharset(String acceptCharset,
                         List<String> acceptableCharsets,
                         List<String> bannedCharsets,
                         boolean anyCharsetAllowed,
                         List<AcceptCharset.ValuedCharset> valuedCharsets) {
        this.acceptCharsetHeader = acceptCharset;
        this.anyAllowed = anyCharsetAllowed;
        this.banned = Collections.unmodifiableList(bannedCharsets);
        boolean isISO8859Explicit = false;
        for (ValuedCharset vCharset : valuedCharsets) {
            if ("ISO-8859-1".equalsIgnoreCase(vCharset.charset)) { //$NON-NLS-1$
                isISO8859Explicit = true;
                break;
            }
        }
        if (!isISO8859Explicit && !anyAllowed) {
            ArrayList<String> acceptableCharsetsTemp = new ArrayList<String>(acceptableCharsets);
            acceptableCharsetsTemp.add(0, "ISO-8859-1"); //$NON-NLS-1$
            this.acceptable = Collections.unmodifiableList(acceptableCharsetsTemp);

            ArrayList<AcceptCharset.ValuedCharset> valuedCharsetsTemp =
                new ArrayList<ValuedCharset>(valuedCharsets);
            valuedCharsetsTemp.add(0, new AcceptCharset.ValuedCharset(1.0d, "ISO-8859-1")); //$NON-NLS-1$
            this.valuedCharsets = Collections.unmodifiableList(valuedCharsetsTemp);
        } else {
            this.acceptable = Collections.unmodifiableList(acceptableCharsets);
            this.valuedCharsets = Collections.unmodifiableList(valuedCharsets);
        }
    }

    /**
     * Provide a list of character sets which are acceptable for the client. If
     * any charset is acceptable with some non-zero priority (see
     * {@link #isAnyCharsetAllowed()}), only character sets more preferable than
     * wildcard are listed.
     * 
     * @return unmodifiable list, never <code>null</code>; the list is sorted
     *         starting with the most preferable charset
     */
    public List<String> getAcceptableCharsets() {
        return acceptable;
    }

    /**
     * Is any character set acceptable? Note that expressions are listed by
     * {@link #getBannedCharsets()}. This means that the value contains wildcard
     * (with non-zero priority) of the header is not present at all.
     * 
     * @return <code>true</code> if any character set is acceptable
     */
    public boolean isAnyCharsetAllowed() {
        return anyAllowed;
    }

    /**
     * A list of non-acceptable (q-value 0) character sets, i.e. exception of
     * {@link #isAnyCharsetAllowed()}.
     * 
     * @return never <code>null</code>; always empty if wildcard is not included
     */
    public List<String> getBannedCharsets() {
        return banned;
    }

    /**
     * Creates a new instance of AcceptCharset by parsing the supplied string.
     * 
     * @param value the Accept-Charset string
     * @return the newly created AcceptCharset
     * @throws IllegalArgumentException if the supplied string cannot be parsed
     */
    public static AcceptCharset valueOf(String value) throws IllegalArgumentException {
        return delegate.fromString(value);
    }

    public String getAcceptCharsetHeader() {
        return acceptCharsetHeader;
    }

    public List<AcceptCharset.ValuedCharset> getValuedCharsets() {
        return valuedCharsets;
    }

    @Override
    public String toString() {
        return delegate.toString(this);
    }

}