antliscence/src/main/org/apache/tools/ant/property/ResolvePropertyMap.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.tools.ant.property;

import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;

/**
 * Class to resolve properties in a map. This class is explicitly not threadsafe.
 * @since Ant 1.8.0
 */
public class ResolvePropertyMap implements GetProperty {
    private final Set<String> seen = new HashSet<>();
    private final ParseProperties parseProperties;
    private final GetProperty master;
    private Map<String, Object> map;
    private String prefix;
    // whether properties of the value side of the map should be
    // expanded
    private boolean prefixValues = false;
    // whether the current getProperty call is expanding the key side
    // of the map
    private boolean expandingLHS = true;

    /**
     * Constructor with a master getproperty and a collection of expanders.
     * @param project the current ant project.
     * @param master the master property holder (usually PropertyHelper)
     * @param expanders a collection of expanders (usually from PropertyHelper).
     */
    public ResolvePropertyMap(Project project, GetProperty master, Collection<PropertyExpander> expanders) {
        this.master = master;
        this.parseProperties = new ParseProperties(project, expanders, this);
    }

    /**
     * Returns the value of a property if it is set.
     * @param name name of the property.
     * @return the property value, or null for no match or for name being null.
     */
    @Override
    public Object getProperty(String name) {
        if (seen.contains(name)) {
            throw new BuildException("Property %s was circularly defined.",
                name);
        }

        try {

            // If the property we are looking up is a key in the map
            // (first call into this method from resolveAllProperties)
            // or we've been asked to prefix the value side (later
            // recursive calls via the GetProperty interface) the
            // prefix must be prepended when looking up the property
            // outside of the map.
            String fullKey = name;
            if (prefix != null && (expandingLHS || prefixValues)) {
                fullKey = prefix + name;
            }

            Object masterValue = master.getProperty(fullKey);
            if (masterValue != null) {
                // If the property already has a value outside of the
                // map, use that value to enforce property
                // immutability.

                return masterValue;
            }

            seen.add(name);

            String recursiveCallKey = name;
            if (prefix != null && !expandingLHS && !prefixValues) {
                // only look up nonprefixed properties inside the map
                // if prefixValues is true or we are expanding the key
                // itself
                recursiveCallKey = prefix + name;
            }

            expandingLHS = false;
            // will recurse into this method for each property
            // reference found in the map's value
            return parseProperties.parseProperties((String) map.get(recursiveCallKey));
        } finally {
            seen.remove(name);
        }
    }

    /**
     * The action method - resolves all the properties in a map.
     * @param map the map to resolve properties in.
     * @deprecated since Ant 1.8.2, use the three-arg method instead.
     */
    @Deprecated
    public void resolveAllProperties(Map<String, Object> map) {
        resolveAllProperties(map, null, false);
    }

    /**
     * The action method - resolves all the properties in a map.
     * @param map the map to resolve properties in.
     * @param prefix the prefix the properties defined inside the map
     * will finally receive - may be null.
     * @deprecated since Ant 1.8.2, use the three-arg method instead.
     */
    @Deprecated
    public void resolveAllProperties(Map<String, Object> map, String prefix) {
        resolveAllProperties(map, null, false);
    }

    /**
     * The action method - resolves all the properties in a map.
     * @param map the map to resolve properties in.
     * @param prefix the prefix the properties defined inside the map
     * will finally receive - may be null.
     * @param prefixValues - whether the prefix will be applied
     * to properties on the value side of the map as well.
     */
    public void resolveAllProperties(Map<String, Object> map, String prefix,
                                     boolean prefixValues) {
        // The map, prefix and prefixValues flag get used in the
        // getProperty callback
        this.map = map;
        this.prefix = prefix;
        this.prefixValues = prefixValues;

        for (String key : map.keySet()) {
            expandingLHS = true;
            Object result = getProperty(key);
            String value = result == null ? "" : result.toString();
            map.put(key, value);
        }
    }
}