org.apache.wicket.util.parse.metapattern.parsers.VariableAssignmentParser.java Source code

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Here is the source code for org.apache.wicket.util.parse.metapattern.parsers.VariableAssignmentParser.java

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/*
 * 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.wicket.util.parse.metapattern.parsers;

import org.apache.wicket.util.parse.metapattern.Group;
import org.apache.wicket.util.parse.metapattern.MetaPattern;
import org.apache.wicket.util.parse.metapattern.OptionalMetaPattern;

/**
 * Parses key value assignment statements like "foo=bar" but also supporting namespaces like
 * "wicket:foo=bar". However the 'key' value returned will contain "wicket:foo". It does not
 * separate namespace and name.
 * 
 * @author Jonathan Locke
 */
public final class VariableAssignmentParser extends MetaPatternParser {
    /** The optional namespace like "namespace:*[:*]" */
    private static final MetaPattern namespace = new OptionalMetaPattern(
            new MetaPattern[] { MetaPattern.VARIABLE_NAME, MetaPattern.COLON,
                    new OptionalMetaPattern(new MetaPattern[] { MetaPattern.VARIABLE_NAME, MetaPattern.COLON }) });

    /** The key (lvalue) like "name" or "namespace:name" or "namespace:name:subname" */
    private final Group key = new Group(new MetaPattern(namespace, MetaPattern.XML_ATTRIBUTE_NAME));

    /** The rvalue of the assignment */
    private final Group value;

    /**
     * Construct a variable assignment parser against a given input character sequence
     * 
     * @param input
     *            The input to parse
     */
    public VariableAssignmentParser(final CharSequence input) {
        this(input, MetaPattern.STRING);
    }

    /**
     * Construct a variable assignment parser against a given input character sequence
     * 
     * @param input
     *            The input to parse
     * @param valuePattern
     *            Value pattern
     */
    public VariableAssignmentParser(final CharSequence input, final MetaPattern valuePattern) {
        super(input);

        // Create group for value pattern
        value = new Group(valuePattern);

        // Pattern for =<value>
        final MetaPattern variableAssignment = new MetaPattern(MetaPattern.OPTIONAL_WHITESPACE, MetaPattern.EQUALS,
                MetaPattern.OPTIONAL_WHITESPACE, value);

        // Set parse pattern to <key>=<value>?
        setPattern(new MetaPattern(MetaPattern.OPTIONAL_WHITESPACE, key,
                new OptionalMetaPattern(variableAssignment), MetaPattern.OPTIONAL_WHITESPACE));
    }

    /**
     * Gets the key part (eg 'foo' in 'foo=bar'). The key will include the optional namespace (eg
     * 'html:foo' in 'html:foo=bar').
     * 
     * @return The key part
     */
    public String getKey() {
        return key.get(matcher());
    }

    /**
     * Gets the value part (eg 'bar' in 'foo=bar').
     * 
     * @return The value part
     */
    public String getValue() {
        return value.get(matcher());
    }
}